venerdì 20 marzo
2015
Workshop sugli sviluppi della ricerca scientifica e tecnologica dell'INRIM
Programma della seconda giornata
9:00
9:20
V. Basso
Functional (non only magnetic) materials
9:20
9:40
M. Kuepferling
Spintronics and Magnonics
9:40
10:00
M. Piazzi
Magnetic refrigeration and magnetocaloric effect.
Theoretical and experimental development at INRIM
10:00
10:20
A. Sola
Spincaloritronics and metrology at INRIM
10:20
10:40
10:40
11:00
F. Rolle
Metrology in Chemistry: some Applications supporting
Quality of Life
11:00
11:20
L. Lolli
Radiometry for Earth Observation
11:20
11:40
M. Fretto
Josephson junctions-based superconductive quantum devices
at INRIM
11:40
12:00
P. Durandetto
Speed up and keep it cool: quantum voltage standards
targets and challenges
12:00
14:00
14:00
14:20
M. Zucca
Misura e caratterizzazione di dispositivi magnetostrittivi
14:20
14:40
A. Manzin
Modeling of nanostructured systems for magnetic particle sensing
and manipulation
14:40
15:00
G. Barrera
Magnetic nanoparticles for biomedical applications
15:00
15:20
G. Conta
Different functionalities in thin films:
from magnetic to semiconducting
15:20
15:40
15:40
16:00
D. Giordano
Osservabilità della rete elettrica di distribuzione in media tensione
16:00
16:20
S. Palumbo
Fino al MegaNewton e ritorno
16:20
16:40
E. Massa
Le costanti di Avogadro e Planck per la ridefinizione del kg
16:40
17:00
A. M. Giovannozzi
Applications of Vibrational Spectroscopy Techniques
in Food Metrology
17:00
17:20
G. Durando
Attività di ricerca del Laboratorio Ultrasuoni
pausa caffè
pausa pranzo
pausa caffè
Functional (non only magnetic) materials
V. Basso, INRIM, Torino, Italy
Functional materials constitute the basic ingredient of any modern, knowledge based and
environmentally friendly, technology. The renewed interest in the electrical energy conversion (i.e.
the electric car) [1], the need to develop novel cooling systems in the solid state [1,2], and the most
recent advances in the "novel electronics" (i.e. spintronics)[3], are all based on the development of
novel materials with special functions associated to particular physical effects. The development of
the measurement methods and the comprehension of the physical roots of the observed effects are
the two fundamental pillars that accompany the very fast developments occurring in material
science.
This talk is devoted to give a short overview on the current scientific activities performed at INRIM
along these lines. We will review: novel extra soft and extra hard magnetic materials, materials for
solid state cooling, materials for spintronic, i.e. materials with enhanced spin Seebeck and spin Hall
effects in magnetic materials and nanostructures. All these topics have in common the fact that only
a deep physical understanding permits to address the future metrological needs.
[1] O. Gutfleisch et al., "Magnetic Materials and Devices for the 21st Century: Stronger, Lighter,
and More Energy Efficient", Adv. Mater. 23, 821 (2011). doi: 10.1002/adma.201002180
[2] M. Valant, "Electrocaloric materials for future solid-state refrigeration technologies", Prog.
Mater. Sci. 57, 980 (2012). doi:10.1016/j.pmatsci.2012.02.001
[3] R. L. Stamps et al, "The 2014 Magnetism Roadmap", J. Phys. D: Appl. Phys. 47 333001
(2014).doi:10.1088/0022-3727/47/33/333001
Spintronics and Magnonics
M. Kuepferling
The discovery of the Giant Magneto-Resistive (GMR) effect performed in 1988 by Albert
Fert and Peter Grünberg, awarded with the Nobel Prize for Physics in 2007, has been the
starting point for the new research field of Spintronics, where the spin of the electron, in
addition to its charge, is exploited to design and fabricate technological applications in the
areas of magnetic storage, magnetic memories, sensors and other ICT devices. The high
potential for application, given the example of GMR effect which lead to the current high
hard disk memory density, has driven an avalanche of research and publications in the last
10 to 15 years.
Spin transport may be a more efficient way to elaborate, transmit and store signals than
the (dissipative) electric current. Spin waves are dynamic magnetization states with
wavelike phase relation between the single localized spins and allow for spin transport
without charge transport. When magnetostatic interaction dominates, their frequencies are
in GHz range, a typical range used in communication technologies, which makes them
interesting for applications. Magnonics, the combination of spintronics and spin waves,
emerged in the recent years as one of the most promising nanotechnologies for
computing devices and magnetic memories. The combination of spintronic devices and
magnonic wave guides offers the possibility of a fast and dissipationless transport of
information by spins instead of electrons that might go beyond the semiconductor
technology.
Within this field, two examples of experimental and theoretical research currently
conducted at INRIM are shown in this presentation
a) magnetic spin torque vortex oscillator, as example for an innovative spintronic
application
b) magnetostatic spinwaves in nanostructured media, as example for spin wave
transport
These examples are two similar phenomena described within the framework of linear and
non-linear magnetization dynamics. Fundamental aspects are pointed out that are in
common with any nanosystem or -device, like the importance of thermal fluctuations or
disorder. Furthermore the potential applicative importance and future perspectives of this
quickly growing research field are emphasized.
This research is supported by the projects PRIN DyNanoMag, JRP SpinCal and ITN Wall
with wide national and international collaboration.
Magnetic refrigeration and magnetocaloric effect. Theoretical and experimental development
at INRIM
M. Piazzi, C. Bennati, C. Curcio, M. Kuepferling, E. Olivetti, V. Basso
The search for environmental-friendly and energy efficient technologies is a mandatory requirement
for our society. Alternative energy sources are definitely needed to provide a sustainable answer to
the ever-growing worldwide electricity demand. In this context room-temperature magnetic
refrigeration, among others, may represent a promising answer to this challenging task. It offers
many advantages as compared to usual vapour-compression cooling: no greenhouse gases involved,
increased devices compactness achievable, noise reduction, gain in cooling efficiency up to ≈ 30%.
The technology is based upon the magnetocaloric effect (MCE), the entropy and adiabatic
temperature changes induced in a magnetic material by variations of an external magnetic field.
Traditionally used in low temperature physics, a renewed interest on this topic has raised after the
discovery in 1997 of giant MCE (GMCE) near room-temperature in Gd5(Si2Ge2). It has been shown
that GMCE is associated to first-order magnetostructural phase transitions. The coupling between
magnetic properties and lattice structure of a system results in a sharp magnetic entropy change
accompanied by crystal symmetry changes and volume variations. Nowadays La(Fe,Si)13 and
(Mn,Fe)2(P,Si) are the state-of-the-art GMCE materials. Open problems include the presence of
slow dynamic processes and magnetic-thermal hysteresis, reducing the magnetic cooling efficiency.
Hence, current research efforts concern the synthesis of unexplored compounds, the development
of new characterization methods and the theoretical modelling that can possibly boost the discovery
of novel materials yielding enhanced MCE properties.
The European Community’s 7th Framework Programme “DRREAM” – Drastically Reduced Used
of Rare-Earth for Applications in Magnetocalorics, enters this field aiming to reduce the use of
Rare-Earth elements in technologies exploiting magnetic phase transitions. Indeed Rare-Earth free
materials are expected to reduce raw material use, wastage and costs. INRIM participates in this
project both on the experimental and theoretical side.
In this talk the results obtained by our group will be presented, concerning:
· the fabrication of transition metals-based alloys, as Mn-based compounds;
· the characterization by means of calorimetry in magnetic field, magneto-optical and electrical
transport measurements (the latter activity held in collaboration with Politecnico of Torino);
· the thermodynamic modelling of magnetic first-order phase transitions involving
magnetically ordered states.
Spincaloritronics and metrology at INRIM A. Sola, M. Kuepferling, E. Ferraro, A. Magni, V. Basso, M. Pasquale In the last few decades the Moore’s law represented a goal for technology industry and, as a consequence, for the research in solid state physics. One of the emerging technology that were born in this framework is spintronics, a new electronics that can exploit the electron’s charge together with its intrinsic spin and its associated magnetic moment in a solid state device. Some of the milestones of spintronics are the observation of spin‐polarized electron injection from a ferromagnetic metal to a normal metal by Johnson and Silsbee [1] and the discovery of giant magnetoresistance independently by Albert Fert [2] and Peter Grünberg [3]. Since these discoveries, many progress of technology in the field of data storage occurred and many new fields of spin manipulation rose. One of these research fields is spincaloritronics that has emerged from the combination of spintronics and thermo‐electricity and has attracted attention thanks to several experimental results of the spin Seebeck effect [4]. This spin analogue of Seebeck effect has a promising role for the thermal generation of a spin current. The longitudinal spin Seebeck effect (LSSE)[5] rises when a temperature gradient is generated in the out of plane direction of a ferrimagnetic layer, typically yttrium iron garnet Y3Fe5O12 (YIG) grown on a gadolinium gallium garnet (GGG) substrate. Because of the LSSE, the YIG layer generates a spin current along the direction of temperature gradient, that is detected by inverse spin Hall effect (ISHE) [6]. This Hall‐type phenomenon determines a charge accumulation due to the spin‐orbit coupling strength that regulates the interaction between electrons and spin currents. It is possible to observe ISHE by means of a paramagnetic metal film deposited over the YIG layer. Since LSSE is detectable only by indirect measurement, the observation of this phenomenon is not yet established in a reliable way. This issue has been emphasized by an international round robin experiment contextually to the JRP Spincal. This experiment is coordinated by INRIM and involves Tohoku University, Ohio State University, Argonne National Laboratory and Bielefeld University. In order to perform a deeper investigation on LSSE, we developed at INRIM a measurement system devoted to the correlation between results of the round robin partners [7]. [1] Johnson, M.; Silsbee, R. H. (1985). Phys. Rev. Lett. 55 (17): 1790–1793. [2] Baibich, M. N.; Broto, J. M.; Fert, A.; Nguyen Van Dau, F. N.; Petroff, F.; Etienne, P.; Creuzet, G.; Friederich, A.; Chazelas, J. (1988). Phys. Rev. Lett 61 (21): 2472–2475 [3] Binasch, G.; Grünberg, P.; Saurenbach, F.; Zinn, W. (1989). Phys. Rev. B 39 (7): 4828 [4] Uchida K, Takahashi S, Harii K, Ieda J, Koshibae W, Ando K, Maekawa S and Saitoh E 2008 Nature 455 778 [5] Uchida, K. I., Adachi, H., Ota, T., Nakayama, H., Maekawa, S., & Saitoh, E. (2010). App. Phys. Lett., 97(17), 172505. [6] Ando, K., Y. Kajiwara, S. Takahashi, S. Maekawa, K. Takemoto, M. Takatsu, and E. Saitohl. Phys. Rev. B 78.1 (2008) 014413 [7] A. Sola, M.Kuepferling, V.Basso, M.Pasquale, T.Kikkawa, K.Uchida, and E.Saitoh. J. Appl. Phys. in press METROLOGY IN CHEMISTRY: SOME APPLICATIONS SUPPORTING
QUALITY OF LIFE
Francesca Rolle, Enrica Pessana, Michela Sega, Giulio Beltramino, Elisabetta Chirivì, Vito
Fernicola, Roberto Gavioso, Daniele Madonna Ripa, Alberto Verdoja
The importance of carrying out accurate and reliable measurements is a fundamental topic in many
different fields and metrology in chemistry can contribute to the reliability of measurement results.
A focus on two activities carried out in the INRiM laboratory for “Gaseous mixtures and organic
analysis” is given.
A consolidated activity concerns the preparation of reference gas mixtures of greenhouse gases (like
CO2) and their precursors (like NOx) by means of the gravimetric method, which is a primary one,
by using a facility entirely realised at INRiM. In addition, the use of another primary method for the
preparation of reference gas mixtures, namely the dynamic dilution technique, is under
development. The realisation of primary standards is fundamental for assuring traceability to the
measurements of gaseous pollutants in the atmosphere, supporting both the needs of the World
Meteorological Organization at international level and the work of laboratories which monitor the
trends of these pollutants at national level.
Another activity is related to the application of metrology to moisture analysis in the framework of
the European EMRP Project SIB64 METefnet “Metrology for moisture in materials”, for the
realisation of the metrological infrastructure for the determination of moisture content in solid
materials. The aim is the development of the measurement capabilities, at national level, for the
determination of moisture in solid and porous materials, for industrial applications and in the food
quality field. For this purpose, there is a need of physico-chemical techniques selective for water, as
coulometric Karl Fischer titration, Evolved Water Vapour analysis and microwave resonance
techniques, which are under investigation and metrological characterisation at INRiM.
Further activity in the gas field will be carried out for improving the establishment of metrological
traceability of CO2, NOx and organic pollutants both in the atmosphere and in different
environmental matrices. In addition, a new activity will concern the analysis of the isotopic ratio of
13
CO2/12CO2 by means of spectroscopic techniques, which is a fundamental parameter for the
monitoring of the increasing trend of CO2 in the atmosphere.
In the field of moisture determination, the activity will be focused both on the investigation of
materials useful for the industrial, pharmaceutical and energetic fields and on the analysis of
moisture in food, also investigating matrices with a potential application as certified reference
materials.
Radiometry for Earth Observation Lapo Lolli E. Taralli, R. Filippo, M. Rajteri, G. Brida “Warming of the climate system is unequivocal … The atmosphere and ocean have warmed, the amounts of snow and ice have diminished, sea level has risen, and the concentrations of greenhouse gases have increased… It is extremely likely that human influence has been the dominant cause of the observed warming since the mid‐20th century” [1]. Remote monitoring of the earth system is crucial to enable better stewardship of the environment to provide the information to policy makers developing appropriate mitigation strategies for climate change. Global observations can only be made from space, and although such observations are being made, the harsh and challenging environment of space limits the uncertainty currently attainable. Satellites require comparison with ‘ground‐truth’ or products from different Earth Observation (EO) missions to improve the uncertainty and the traceability through all stages of data production: pre‐
flight and post‐launch calibration and validation, and all the intermediate processing steps. These problems have been addressed within the European Metrology Research Programme MetEOC and MetEOC‐2 (Metrology for Earth Observation and Climate) [2]. Calibration and comparison of remote sensing satellite data can be performed based on “vicarious” sites. To perform autonomous SI traceable measurements of geographically distributed surface spectral reflectance/radiance for vicarious test sites, a multi‐band radiometer sensing system based on light‐
emitting diodes (LEDs) has been developed. Temporally continuous measurement of the land reflectance in 4 spectral bands, from 350 nm to 900 nm, can be acquired. The system has the ability to regularly re‐calibrate autonomously and in the field, communicating results to a remote home base. Moreover, to extract information from satellite images, it is necessary to apply 3D radiative transfer (RT) models, that require detailed mathematical formulations of the spectro‐directional behavior of individual foliage elements, in order to simulate the response of satellite or in situ measuring devices. In particular, for the simulation of measurement campaigns, the specular component of foliage scattering becomes important. This problem has been investigated by developing and building a leaf goniometer for in situ spectro–directional measurements of bi‐directional reflectance and transmission factor [3] of individual leaves under controlled illumination conditions and within a short amount of time to avoid the leaves degradation [4]. [1] Intergovernmental Panel on Climate Change ‐ Sept 2013 [2] http://www.emceoc.org/index.html. [3] Nicodemus et al (1977) NBS Monograph MN‐160 (Washington, DC: NBS) [4] Lolli et al, Metrologia 51 (2014) S309–S313 Josephson junctions-based superconductive quantum devices in INRIM
Matteo Fretto, Natascia De Leo, Luca D’Ortenzi, Andrea Sosso, Vincenzo
Lacquaniti.
Low critical temperature (Tc) superconductor junctions are still the best candidates for many smallscale applications of superconductivity due to their robustness, reliability and reproducibility; in
particular niobium technology is widely used in superconductive fast electronics (Rapid Single
Quantum Flux – RSFQ), in micro and nano Superconductive Quantum Interference Devices
(SQUIDs) and in programmable voltage standards for electrical metrology.
INRiM
superconductive group is active in these research fields and has obtained interesting results in each
topic.
I will present an innovative overdamped Josephson junction based on a Superconductor-Normal
metal-Insulator-Superconductor (SNIS) structure developed at INRiM and some of its most
promising applications as:
 The fabrication of a SNIS 1 Volt Programmable Voltage Standard, its temperature
behaviour and the current research activity in the implementation of a liquid helium free
measurement set-up by using cryocoolers, in the framework of the EMRP project “QWave”[2].
 The optimization of electrical parameters and the miniaturization of SNIS junctions for
RSFQ [3] using Electron Beam Lithography (EBL) adapted processes in the framework of
the European FLUXONICS network.
 The realization and the characterization of ultra-high sensitive nanoSQUIDS by mean of a
new fabrication technique based on FIB (Focused Ion Beam) sculpting technique [4].
[1] V. Lacquaniti, N. De Leo, M. Fretto, A. Sosso, F. Muller, J. Kohlmann; “1 V programmable voltage standards based
on SNIS Josephson junction series arrays”, Supercond. Sci. Technol. , vol 24, 045004 (2011).
[2] A. Sosso, B. Trinchera, E. Monticone, M. Fretto, P. Durandetto, V. Lacquaniti; “Temperature stability of SNIS
Josephson arrays between 4.2 K and critical temperature in cryocooler”, IEEE Trans. Appl. Supercond., vol 25, issue 3,
1955913, (2014)
[3] P. Febvre, D. Bouis, N. De Leo, M. Fretto, A. Sosso, V. Lacquaniti; “ Electrical parameters of niobium-based
overdamped superconductor-normal metal-insulator-superconductor Josephson junctions for digital applications”,
Journal of Applied Physics, vol. 107, 103927 (2010)
[4] C. Granata, A. Vettoliere, R. Russo. M. Fretto. N. De Leo, V. Lacquaniti; “Three dimensional spin nanosensor
based on reliable tunnel Josephson nano-junctions for nanomagnetism investigations”, Applied Physics Letters, vol. 103,
issue 10, 102602 (2013)
Speed up and keep it cool:
quantum voltage standards targets and challenges
Paolo Durandetto, Andrea Sosso, Bruno Trinchera, Matteo Fretto, Eugenio Monticone, Vincenzo Lacquaniti
Research on Josephson quantum standards is aiming at a fundamental change in the Metrology of
the volt for AC and arbitrary waveforms. Whilst only DC measurements have enjoyed a quantum
basis up to now, in the future direct traceability to the quantum volt, based on the Josephson effect,
will be provided with no distinction between DC and AC measurements and a direct link to the SI
will be guaranteed at operating frequencies of up to the MHz, fulfilling the requirements set
nowadays by precision integrated circuits and instrumentation for digital Metrology. Programmable
voltage standards converting a digital code into a quantum-accurate value are already available in
primary laboratories. Even more advanced standards to convert sub-nanosecond binary coded
pulses into any arbitrary signal with quantum accuracy are now actively developed and tested.
INRiM has a long tradition in Josephson voltage standard research, with significant achievements
epitomized by the SNIS technology for programmable devices, and is currently involved in
cooperative research within several EURAMET projects.
The presentation will focus on the recent and ongoing activities on helium-free operation with both
types of Josephson standards: programmable SNIS arrays and pulsed devices fabricated by PTB.
Helium-free operation is important for ease of use, but as a way to reduce cable effects is now a
crucial issue to overcome frequency-related limitations to the accuracy of the standard. Yet,
thermalization problems not faced with helium cooling are still challenging. Some of our recent
results indicate that a careful design of the cooling setup allows operation with short cables without
affecting the cooler effectiveness. If confirmed, cooling Josephson standards without helium will
prove to be a benefit to speed up the synthesized quantum signal frequency rather than another
obstacle to overcome.
Misura e caratterizzazione di dispositivi magnetostrittivi.
M. Zucca, A. Hadadian, O. Bottauscio
[email protected]
La capacità dei materiali magnetostrittivi di convertire una corrente elettrica in una forza meccanica
con lo stesso andamento temporale è di interesse nel campo dell’attuatoristica, nel posizionamento di
precisione, nella compensazione attiva delle vibrazioni e, in prospettiva, nella metrologia delle forze
(effetto magnetostrittivo diretto) e delle coppie (effetto Wiedemann). La rigidezza di questi materiali
(fino a 700 MPa la resistenza a compressione e circa 20 GPa il modulo di Joung), la loro resilienza
(FeGa) e la risposta fino alle frequenze soniche (10 kHz) li rendono particolarmente interessanti per
vari campi scientifici ed applicativi.
La peculiare vocazione di tali materiali alla conversione delle grandezze meccaniche tempo varianti
(forze e coppie) in segnale elettrico (effetto Villari ed effetto Matteucci) è di interesse nel campo della
sensoristica e dell’energy harvesting, tenuto anche conto dell’elevata energia specifica (fino a 25 kJ/m3
per il Tb0.3Dy0.7Fe1.92).
I sistemi magnetici basati su tali materiali sono soggetti ai problemi di non-linearità ed isteresi tipici
dei materiali ferromagnetici . A ciò si aggiunge la loro peculiarità magnetomeccanica che fa si che il
loro comportamento globale sia altamente complesso e quindi soggetto, per molti aspetti, ad attività di
ricerca. La trattazione accurata dei materiali e dei relativi sistemi richiede pertanto specifici approcci
modellistici e sperimentali.
Fin dal 2006 l’INRIM ha sviluppato strumenti e dispositivi per la caratterizzazione e lo studio di questi
sistemi. Una caratterizzazione riferibile, in particolare dinamica, ed una approccio modellistico
“snello” ma non troppo semplificato, adatto a controlli di tipo real-time, rimangono tuttavia una sfida.
Nell’ambito del contesto sopra descritto si intende illustrare l’attività svolta fino ad oggi, in particolare
presso l’INRIM, e delinearne possibili sviluppi ed applicazioni.
Modeling of nanostructured systems for magnetic particle sensing and manipulation
Alessandra Manzin
Bio-functionalized magnetic particles can be advantageously used as colloidal mediators for
hyperthermia treatment, as well as to label, deliver and separate biomaterials, also thanks to the
capability to be magnetically manipulated and transported, independently of normal microfluidic
and biological processes. Magnetic labels have several advantages over conventional fluorescence
and chemiluminescence systems, since their magnetic moment produces a detectable signal, a
localized magnetic field, and allows the application of controlled forces using external magnetic
field gradients.
This has given a boost to the basic research on solid‐state magnetic sensors for single magnetic
particle resolution (e.g., magnetoresistive and Hall effect devices) and their further integration in
microfluidic platforms for lab‐on‐chip biomedical applications. At the same time, efforts have been
made to engineer ad-hoc magnetic nanostructures for drug delivery and selective manipulation of
cells based on magnetically-labeled bio-particles.
A valid support to the design and optimization of such complex systems can be provided by ad-hoc
numerical models, able to simulate the specific involved physical phenomena, providing insights
into the linked nanoworld. In this framework, the present seminar aims at illustrating some
modeling activities in progress at INRIM, oriented toward the following research fields:
- study of nanostructured systems for single particle detection (e.g., miniaturized Hall devices made
of graphene [1-3] and magnetoresistive sensing elements based on domain wall control [4, 5]);
- simulation of magnetic nanoconveyors and nanopatterned films [6] for possible applications in
magnetic bio-sensing, targeted drug delivery and bio-particle manipulation.
Finally, a short overview of the most challenging perspectives will be given, introducing other
potential candidates for high-sensitivity magnetic field detection based, respectively, on magnetic
systems exhibiting extraordinary Hall effect and graphene spintronic devices.
[1] A. Manzin, E. Simonetto, G. Amato, V. Panchal, and O. Kazakova, Modeling of graphene Hall effect sensors for microbead
detection. J. Appl. Phys. (in press).
[2] V. Panchal, A. Lartsev, A. Manzin, R. Yakimova, A. Tzalenchuk, and O. Kazakova, Visualisation of edge effects in side-gated
graphene nanodevices. Scientific Reports 4, 5881 (2014).
[3] R.K. Rajkumar, A. Asenjo, V. Panchal, A. Manzin, O. Iglesias-Freire, and O. Kazakova, Magnetic scanning gate microscopy of
graphene Hall devices. J. Appl. Phys. 115, 172606 (2014).
[4] A. Manzin, V. Nabaei, H. Corte-León, O. Kazakova, P. Krzysteczko, and H.W. Schumacher, Modeling of anisotropic
magnetoresistance properties of permalloy nanostructures. IEEE Trans. Magn. 50, 7100204 (2014).
[5] H. Corte-León, V. Nabaei, A. Manzin, J. Fletcher, P. Krzysteczko, H.W. Schumacher, and O. Kazakova, Anisotropic
magnetoresistance state space of permalloy nanowires with domain wall pinning geometry. Scientific Reports 4, 6045 (2014).
[6] M. Coïsson, A. Manzin, G. Barrera, F. Celegato, E. Enrico, P. Tiberto, and F. Vinai, Anisotropic magneto-resistance in Ni80Fe20
antidot arrays with different lattice configurations. Applied Surface Science 316, pp. 380-384 (2014).
Magnetic nanoparticles for biomedical applications
G. Barrera1,2
1
INRiM, Strada delle Cacce 91, I-10135 Torino, Italy
Chemistry Dept,.Università di Torino, Torino, I-10125, Italy
2
Nowadays magnetic nanoparticles are widely used for a variety of technological applications such as ink-jet technology,
ferrofluids for seals, bearings and dampers in cars and other machines, magneto-optic recording devices, water purification,
and giant magnetoresistive devices. In recent years, nanothechnology has become the most growing area for health care and
life science. In particular, an increasing interest to exploit magnetic systems in biomedical applications with different purposes
has emerged owing to their easily tunable magnetic properties and to the ability to be manipulated and driven by an external
magnetic field gradient.
Nanobiomagnetic applications, including magnetic resonance imaging contrast-enhancement agents, targeted drug delivery,
bioseparation and magnetically induced hyperthermia are becoming prominent and the integration of magnetic materials with
biological molecules and therapeutics are inducing the development of hybrid materials with advanced properties [1]. To
support their exploitation, reliable and reproducible magnetic characterizations are needed in the technological environment
where the magnetic nanomaterials are used.
In this talk, two main categories of magnetic nanoparticles for biomedical applications will be discussed. The first is
represented by free-standing magnetic nanodisks obtained by a bottom up nanolithography process (i.e. Ni80Fe20) having
controlled diameter and ferromagnetic properties. Such nanostructures, either as arrays in a magnetic thin film or dispersed in
ethanol, are characterised by a magnetisation process typical of vortex nucleation with a higher coercive field, as observed by
MFM technique. This feature can be exploited for application in hyperthermia and drug-delivery [2]. Standard magnetic
characterizations together with a novel method to measure hysteresis loops of a single nanostructure by Magnetic Force
Microscopy will be briefly presented.
The second class is represented by more conventional magnetite nanoparticles with a size of 5-6 nm that were synthesized by
the chemical route of thermal decomposition of Fe(acac)3 and subsequently coated with a silica shell. Both kind of asproduced powders were mixed with a photocurable resin obtaining two magnetic nanocomposites with the same nominal
amount of magnetic material. The static magnetic properties of the two nanopowders and the corresponding nanocomposites
were measured in the 10 K - 300 K temperature range by a VSM magnetometer. The FC/ZFC curves reveal a high degree of
particle aggregation in the Fe3O4 nanopowder, which is partially reduced by silica coating and strongly decreased by
dissolution in the host polymer. Analysis of magnetic data and the comparison with TEM image analysis allow to obtain
detailed information on the nanoparticle size distribution and about the effective magnetic anisotropy of the particles. In all
considered materials the nanoparticles are magnetically interacting, the interaction strength being a function of nanoparticle
environment and being the lowest in the nanocomposite containing bare, well-separate Fe3O4 particles. All samples behave as
interacting superparamagnetic materials instead of ideal superparamagnets and follow the corresponding scaling law [3].
In both kind of system, nanodisks and nanoparticles, the next perspectives will be the optimization of their magnetic
properties for applications. One major issue will be the study of the biocompatibility of nanomagnetic materials together with
understanding the correlation between the physical properties of magnetic nanoparticles and the heating power by
hyperthermia measurement.
[1] Nguyen T. K. Than, Magnetic nanoparticles: from fabrication to clinical applications, CRC Press, New York, 2012.
[2] P. Tiberto, G. Barrera, F. Celegato, G. Conta, M. Coïsson, F. Vinai, F. Albertini, Journal of Applied Physics, 17, 17, 2015
[3] P. Allia, G. Barrera, P. Tiberto, T. Nardi, Y. Leterrier, M. Sangermano, Journal of Applied Physics,116, 113903, 2014.
Different functionalities in thin films: from magnetic to semiconducting
G. Conta
Abstract. Nanostructured materials are currently investigated for their unusual and innovative properties (electrical, magnetic,
mechanical), which make them suitable for a range of different applications including spintronics, biomedicine, high-performance
semiconductors, energy storage, catalysis. Within this framework, two different very up-to-date nanostructured systems will be
presented in this talk.
The first part of this talk is devoted to a new class of materials that envelope magnetic and semiconducting features: Diluted
magnetic semiconductors (DMS). DMSs could represent a possible road to realize and integrate spin transport electronics through the
synthesis of a semiconductor supporting spontaneous spin polarization, preferably, up to room temperature. One possible way to
introduce such behavior is by adding the transition metal manganese to a semiconductor host in diluted concentration (10%) that
brings up both free carriers and localized moments. In these systems the randomly distributed spins of Mn ions show collective
ferromagnetic ordering. It is even more interesting that, in the diluted concentration regime, the exchange interaction between
adjacent localized moments is mediated by the free carriers, particularly by holes in p-type diluted magnetic semiconductor (p-DMS).
The existence of a strong interaction between subsystems of localized spins and effective mass carriers is the signature of any
genuine DMS. This interaction accounts for the two main features of this class of compounds: giant Zeeman splitting of the bands
and the formation of magnetic polarons [1,2]. Thus ferromagnetic properties of DMSs can be controlled by varying the net acceptor
concentration as well as by gating or illumination. It was reported that this class of materials offers new possibilities for practical
realization and study of current induced magnetization switching and is known that ferromagnetic semiconductors can be used as an
epitaxially integrated spin-polarizer and to implement spin field-effect transistors [3,4]. DMS based on elemental semiconductors are
of great interest either for researchers in condensed matter physics and for technologists because of the coexistence of both
semiconducting and magnetic behaviors, the integrability in mainstream silicon based technology and the transition metals low
equilibrium solubility. Advances in epitaxial growth technology, such as molecular beam epitaxy (MBE), have made possible to
grow a variety of different diluted alloys with very accurate control of the layers thickness and doping level. Germanium manganese
(Ge1-xMnx) diluted alloys had attracted attention since the discover reported in 2002 by Park et al. of ferromagnetic order in a thin
epitaxial layer of Mn doped Ge, due to the huge variety of magnetic behavior that is linked with the tendencies of the transition metal
ions to segregate in the semiconductor host, forming nanoclusters or nanocolums, which are themselves ferromagnetic [5]. In this
presentation I will show the main achievement and issues related to the growth and characterization of amorphous and epitaxial
diluted alloy Ge1-xMnx reached by my group at the INRiM QR laboratories and the strategies for future development.
In the second part I will talk about a new class of porous magnetic alloys that are appealing materials for biomedicine, energy storage
and catalysis: meso- and nano-porous magnetic materials obtained through selective dealloying of magnetic thin films. A chemical or
electrochemical process dissolves one or more metallic components from a precursor alloy [6]. These systems are an interesting class
of materials for future development in the field of magnetism and condensed matter physics and are of technological interest for
catalysis and water purification. These materials are easily functionalizable and combine advantages in view of the magnetic carrier's
therapeutic functionality to treat tumors [7,8]. Here I will present the approach made to the realization of such support materials and I
will discuss the possible roads to the implementation of the cited technological application.
[1] Dietl, T., Ohno, H (2014) “Diluted ferromagnetic semiconductor: Physics and spintronic structures.”, doi: 10.1103/RevModPhys.86.187
[2] Pinto, N., Morresi, L., Ficcadenti, M., Murri, R., Orazio, F. D., Lucari, F., … Amato, G. (2005) “Magnetic and electronic transport percolation in
epitaxial Ge1 – x Mnx films.”, doi:10.1103/PhysRevB.72.165203
[3] Matsukura, F., Tokura, Y., Ohno, H., (2015) “Control of Magnetism by electric fields” Nature Nanotechnology, doi: 10.1038/nnano.2015.22
[4] Ohno, Y., D. K. Young, B. Beschoten, F. Matsukura, H. Ohno, and D. D. Awschalom, (1999) “Electrical spin injection in a ferromagnetic
semiconductor heterostructure,” Nature 402, 790, doi:10.1038/45509
[5] Jamet, M., Barski et al. (2006). “High-Curie-temperature ferromagnetism in self-organized Ge1-xMnx nanocolumns” Nature Materials, 5(8),
653–9. doi:10.1038/nmat1686
[6] Li, W. C, Balk, T., J. (2009). “Achieving finer pores and ligaments in nanoporous palladium-nickel thin films” Acta Materialia, doi:
10.1016/j.scriptamat.2009.10.009
[7] Shashishekar P et al. “Nanoporous Material for biomedical devies”, Springer (2008) JOM, Volume 60, Issue 3, pp 26-32.
[8] Chen, F.-H., Zhang, L.-M., Chen, Q.-T., Zhang, Y. & Zhang, Z.-J., (2010) “Synthesis of a novel magnetic drug delivery system composed of
doxorubicin-conjugated Fe3O4 nanoparticle cores and a PEG-functionalized porous silica shell”, Chem. Commun., The Royal Society of Chemistr8,
46, 8633-8635
Osservabilità della rete elettrica di distribuzione in media tensione
Domenico Giordano
La rete di distribuzione dell’energia elettrica esercìta in media tensione (RMT) era storicamente pensata per un flusso di
potenza unidirezionale: dalla trasmissione alla distribuzione di prossimità, con una ridotta se non inesistente capacità di
gestione centralizzata (rete passiva).
La vasta diffusione di impianti per la produzione di energia elettrica da fonti rinnovabili (solare, eolico, ...), distribuiti in
modo capillare sul territorio e connessi direttamente alla RMT, richiede un ripensamento di tutto il sistema di gestione
di tali reti. In questo nuovo contesto, al fine di garantire la continuità di servizio, un’adeguata stabilità di tutto il sistema
elettrico e una qualità della potenza elevata, risulta necessaria una trasformazione della RMT da passiva ad intelligente
(smart). In altre parole, occorre automatizzare e gestire in modo centralizzato il nuovo flusso bidirezionale dell’energia
elettrica.
Priorità nell’ambito della ricerca a supporto di tale rivoluzione sono il miglioramento dell’osservabilità della rete e,
conseguentemente, lo sviluppo di sensori avanzati per l’identificazione di anomalie. Si stima, infatti, una perdita di
150 miliardi di euro all’anno in Europa a causa di una cattiva qualità dell’energia fornita agli utenti.
In questo contesto, riveste notevole importanza lo sviluppo di trasduttori di nuova concezione e sistemi con prestazioni
estese, che concorrono al miglioramento dell’osservabilità richiesta. L’attività di ricerca attualmente in corso all’INRIM
è focalizzata su quattro temi:
 Progettazione, mediante il supporto di strumenti numerici, e sviluppo di trasduttori elettronici, per la misura di
tensione e corrente, caratterizzati da un’ampia gamma di frequenza di impiego.
 Sviluppo di sistemi per la caratterizzazione di trasduttori con forma d’onda reale.
 Sviluppo di sistemi Real-Time per il miglioramento del comportamento dinamico di trasformatori di misura, al
fine di renderli idonei all’impiego in catene per la misura di fasori sincronizzati e per l’analisi della qualità
della potenza.
 Sistemi di misura (trasduzione – estrapolazione dei parametri – storage) per misure di Power Quality nella
RMT.
Le competenze acquisite hanno permesso all’INRIM di estendere le proprie capacità metrologiche, di ideare e
sviluppare trasduttori di tensione e corrente con elevate prestazioni metrologiche e di allestire sistemi di misura,
accuratamente caratterizzati, che vanno dalla trasduzione alla misura dei parametri di power quality da impiegarsi insitu.
Durante la presentazione verranno esposti alcuni sviluppi dell’attività, svolta in collaborazione con il Politenico di
Torino, e indirizzata allo studio in laboratorio del comportamento di trasduttori non convenzionali sottoposti a
grandezze calcolate con algoritmi che simulano una rete elettrica in tempo reale.
FinoalMegaNewtoneritorno
S. Palumbo, A. Germak La realizzazione e la disseminazione effettuata all’IRIM del campione nazionale dell’unità di forza, il newton, garantisce la riferibilità delle misure al SI, nei numerosi settori tecnologici, scientifici ed industriali del Paese. Recenti necessità industriali, emerse a livello nazionale, europeo ed internazionale, hanno spinto ad effettuare attività volte ad estendere la riferibilità verso la parte alta della scala (meganewton) e a valutare anche possibili estensione verso la parte bassa (micronewton). Per quanto riguarda il meganewton, dove la richiesta industriale è forte ed in continua crescita, si possiede già un solido know‐how tecnico e scientifico. La sfida è quella di estendere ulteriormente la scala, attualmente realizzata fino ad 1 MN con macchina a pesi diretti e a 10 MN con pressa idraulica (ma con riferibilità al PTB), e quindi la riferibilità all'industria nazionale. Per fare ciò è stato sviluppato all’INRIM, all’interno di un progetto EMRP, un trasduttore di forza di tipo build‐up a sei componenti da 5MN, con il quale sarà possibile estendere la riferibilità interna da 1 MN fino a 5 MN. Partendo da questo, sarà poi possibile sviluppare sistemi di misura fino a 25 MN per rispondere alla richiesta industriale di riferibilità delle misure che si avvicina sempre più ai 30 MN e oltre. Inoltre è stata progettata una nuova macchina campione di forza a pesi diretti (con possibilità di cedere all'industria italiana il know‐how per la sua commercializzazione) per estendere il numero di centri accreditati alla taratura. Inoltre è in fase di studio un sistema di amplificazione della forza per raggiungere il range del meganewton. Per quanto riguarda invece il range del micronewton, dove la richiesta industriale è ancora in fase embrionale, il problema principale riguarda l'impossibilità di usare le tradizionali macchine campione di forza. Si vogliono perciò studiare sistemi di generazione della forza che non si basano più su masse nel campo gravitazione ma sul altri sistemi. Allo stesso modo, i trasduttori di forza finora realizzati non sono sufficientemente sensibili per misurare forze di tale entità. Per questo motivo è allo studio la possibilità di utilizzare polimeri nanocompositi piezoresistivi. Le costanti di Avogadro e Planck per la ridefinizione del kg. Enrico Massa Il futuro riassetto del Sistema Internazionale prevede la realizzazione del kg a partire dalla costante di Planck. La CGPM ha stabilito regole e vincoli affinché possa avvenire il cambiamento. Attualmente solo due raffinate tecniche sperimentali hanno raggiunto le incertezze richieste per la ridefinizione. Il primo approccio utilizza la determinazione della costante di Avogadro, il secondo metodo è rappresentato dal confronto tra potenze meccaniche ed elettriche. Il seminario vuole presentare lo stato dell’arte dei due esperimenti che rappresenteranno la mise en pratique del futuro kg. Applications of Vibrational Spectroscopy Techniques
in Food Metrology
A. M. Giovannozzi
Vibrational Spectroscopy techniques, mainly Infrared and Raman Spectroscopy, are well
established tools in analytical chemistry because they provide a high specificity of detection
(IR or Raman spectrum as molecular fingerprint), a rapid characterization of the system without
sample destruction and with minimal sample preparation, and potentially giving portability for
analysis in situ and in-line which is highly required by the industry. Moreover, the combination
of Raman Spectroscopy with nanotechnology, i.e. gold and silver nanoparticles (NPs), is able
to enhance the Raman signal of a factor close to 1011, increasing enormously the sensitivity of
the technique (close to single molecule detection) and opening new possibilities of applications
especially in food science. Since a metrological approach to food analysis is strongly needed in
a society where consumers require high-quality products, known and safe food composition,
certification and reassurance on product’s origin, we decided to exploit vibrational
spectroscopy features to develop new metrologically underpinned methodologies of
measurements for food analysis. In this talk, I will show some examples of metrological
methodologies based on vibrational spectroscopies for the detection of toxic compounds
fraudulently added in food matrices1 and for the quantification of organic analytes on
industrially relevant surfaces2,3, which were developed in the framework of the following
EMRP Projects: Ind15 SurfChem (Traceable quantitative surface chemical analysis for
industrial applications), NewRaman02 (Metrology for Raman Spectroscopy) and Ind56 QAIMDS (Chemical metrology tools to support the manufacture of advanced biomaterials in the
medical device industry). Moreover, since Titanium dioxide (TiO2) NPs are commonly used in
a lot of food products and recent studies have demonstrated their toxicity in in vitro analysis,
the bio-accumulation of TiO2 NPs standard materials with known shape and composition was
evaluated in the C. elegans worm model system, in order to provide robust metrology tools in
toxicity analysis. Preliminary results obtained on the in vivo localization of TiO2 NPs will be
shown in the framework of the FP7 Project SetNanometro where INRIM is the coordinator.
This study is performed in collaboration with Mario Negri Institute.
[1] A.M. Giovannozzi et al., “Rapid and sensitive detection of melamine in milk with gold
nanoparticles by Surface Enhanced Raman Scattering”, Food Chemistry, 159, 250 (2014).
[2] A.M. Giovannozzi et al., “Traceable measurement of specific organic species at industrially
relevant surface by infrared spectroscopy”, Surface and Interface Analysis, 46, 915 (2014).
[3] L. Mandrile et al., “Direct detection and quantification of molecular surface contaminants
by Infrared and Raman spectroscopy”, Analytical Methods, 2015, DOI: 10.1039/C4AY02850C.
Attività di ricerca del Laboratorio Ultrasuoni
Personale coinvolto: Giovanni Durando (Tecnologo III livello);
Claudio Guglielmone (Ricercatore III livello)
Stato dell’arte:
L’impiego degli ultrasuoni in medicina ha conosciuto un’espansione costante negli ultimi
cinquant’anni. Ormai da tempo le tecniche basate su ultrasuoni rappresentano un settore
estremamente consolidato nel panorama della diagnostica per immagini, nella terapia
oncologica e il rilascio controllato di farmaci mediati da un campo ultrasonoro.
Punto di forza della diagnostica ultrasonora è l’estrema versatilità, la quale ha consentito
una diffusione capillare delle metodiche ecografiche e flussimetriche in quasi tutti i settori
della medicina.
In ambito terapeutico l’applicazione degli ultrasuoni risulta in forte sviluppo, non solo nei
campi consolidati che sfruttano gli effetti di ipertermia, ma anche e soprattutto in aree
emergenti di grande interesse come quella degli HIFU, High Intensity Focused Ultrasound,
per l’ablazione di aree molto circoscritte di tessuti biologici.
Si assiste ad un’intensificazione delle ricerche fondamentali sull’interazione degli
ultrasuoni con la materia biologica, in partcolare sulle applicazioni in ambito farmacologico
che sfruttano gli effetti meccanici legati al fascio ultrasonoro.
Abstract:
Oltre alle consuete attività previste in ambito normativo legate all’IEC, TC87 Ultrasonics
e EURAMET TCAUV-SC Ultrasound and Underwater Acoustic, nel corso dell’ultimo
decennio il Laboratorio Ultrasuoni ha intensificato la propria attività ricoprendo un ruolo di
via via crescente sia in ambito nazionale che internazionale.
Le principali attività che verranno illustrate sono connesse con la:
- Misura di potenza ultrasonora da 10 mW a 300 W per valori di frequenza da 1 MHz
a 15 MHz, mediante sistema di misura basato su bilancia a forza di radiazione e
sistema basato su cella di carico immergibile, brevetto INRIM numero
TO2010A000383 dal titolo “Procedimento per la misura della conduttanza
ultrasonora e relativo sistema di misura”;
- Caratterizzazione di campi ultrasonori e relativa misura di tutti i parametri previsti
dalle norme IEC mediante sistema a scansione triassiale e set d’idrofoni (ad ago, a
membrana, a fibra ottica);
- Misura d‘innalzamento di temperatura indotto da fascio US, con tecniche diverse e
complementari: utilizzando termocamera, termoresistenze e fibra ottica in laboratorio
e in situ;
- Realizzazione e caratterizzazione di sistemi ad ultrasuoni per lo studio di trattamenti
farmacologici, utilizzabili sia in vitro che in vivo.
Principali risultati:
Il livello delle attività svolte ha permesso all’INRIM di partecipare con successo a due
progetti internazionali in ambito EURAMET:
 Programma di ricerca iMERA: call HEALTH 2007 – progetto EBCT, External Beam
Cancer Therapy.
 Programma di ricerca EMRP: call HEALTH 2010 – progetto DUTy, Dosimetry for
Ultrasound Therapy, WP4 -Intercomparison of method- INRIM WP leader.
L’istituto diventa uno dei principali interlocutori e punto di riferimento normativo riguardo
le attività di verifica delle prestazioni di apparti per terapia (principalmente fisiatria e
oncologia) basate su ultrasuoni. A conferma di questo il 23-24 Maggio 2013, presso le
strutture dell’INRIM, viene svolto, in collaborazione con l’Associazione Italiana Fisica
Medica, il corso: Focused Ultrasound in Research and Therapy che vede coivolti circa 70
partecipanti, principalmente medici e fisici medici.