| 26 febbraio
Unité Mixte de Physique CNRS/Thales, Palaiseau, France
Novel paths for rf applications based on spintronics
Spintronics consists on manipulating magnetic electronic spins rather than, or in addition to, charges
through electrical currents and/or magnetic fields. This technology has revolutionized the market of read-head
applications and other types of magnetic sensors. Recently, a lot of promising studies have been done for active
elements such as memories (see for example the recent developments on perpendicular STT-MRAM), spin transistors
and more generally logic spin gates; however, those functionalities are far from being implemented into real
devices. Nevertheless, we believe that concerning radio-frequency (rf) applications, spintronics is now mature
enough for proposing interesting and industrially attractive active functionalities and foster the development of a new
generation of rf devices such as filters, frequency detectors, synthesizers, etc=85 In this seminar I will present
some of the recent works of our laboratory on the subject.
The main brick for this new generation of rf applications  is the spin-transfer nano oscillator
(STNO), which is a magnetic tunnel junction (MTJ) controlled by a dc current. In particular, we are focusing on
vortex-based STNOs, consisting of an MTJ where the free layer is in the magnetic vortex configuration, separated
from a synthetic anti-ferromagnetic polarizer layer by an MgO barrier. The vortex consists of a circular in-plane
magnetization with a central out-of-plane core, which can be excited by a dc current, Idc, resulting in a
steady gyrotropic motion of the vortex core . This motion is transformed into an rf signal in the MHz/GHz range,
through the tunnel magnetoresistance (TMR) effect. A phase-locked loop (PLL) implementation can be used to
further improve the characteristics of such oscillator. Our latest achievements make us confident that a synthesizer
based on vortex STNOs will be good enough for device operations.
Furthermore, the vortex core can be resonantly excited by an rf current, Irf, if the frequency
of the current matches the frequency of the gyrotropic mode , which is the main ingredient for a spintronic frequency
detector. In this context, I will briefly present a new type of STNO frequency detector based on vortex core expulsion,
displaying promising features which can potentially constitute the basis of a new generation of rf applications.
I will also present some novel ideas on STNO-based associative memories : by mimicking the
behavior of our brain, we will consider an array of STNOs and take advantage of their mutual synchronization to
perform associative memory functionalities.
Another interesting use of spintronics for rf application resides in the field of magnonics, i.e., the use
of spin waves excitations (magnons) for information treatment. I will show that the information can be encoded
in the phase of the magnetostatic spin wave and easily manipulated; miniaturized and low energy consumption devices
for both logic  and rf functionalities, e.g., a magnonic filter, can be indeed conceived.
I acknowledge financial support from ANR agency (SPINNOVA ANR-11-NANO-0016; MEMOS ANR-14-CE26-0021-03;
NANOSWITI ANR-11-BS10-003-05) and EU FP7 grant (MOSAIC No. ICT-FP7-n317950).
1. Building blocks: N. Locatelli et al., Nature Mater. 13, 11 (2014)
2. Vortex STNO: A. Dussaux et al., Nature Commun. 1, 8 (2010)
3. Detection: A. S. Jenkins et al., Appl. Phys. Lett. 105, 17 (2014)
4. Associative memories: MEMOS ANR-14-CE26-0021-03
5. Magnonics: Chumak et al., Nat. Commun. 5, 4700 (2014) & ref. therein
| 19 febbraio
Mikhail Aleksandrovich Malygin
Head of the Department of Industrial Metrology
D.I. Mendeleyev Institute for Metrology (VNIIM), Russia
Laboratory of Metrology of magnetic measurements and nondestructive testing at UNIIM
The talk aims to present our lab, our achievements and perspectives for possible further collaboration
and finally to get some experience exchange. The presentation will briefly introduce metrological system
of Russia, distribution of centres and institutes in the country. After that location and significance of
UNIIM and presented laboratory will be determined, and then presentation will focus on the list of
measurement capabilities and activities that our laboratory is specialized on, adding some general information.
| 19 febbraio
Università degli Studi di Bari "Aldo Moro", Politecnico di Bari
Dipartimento Interateneo di Fisica "M. Merlin"
CNR - Istituto di Fotonica e Nanotecnologie
Trace gas sensing and imaging with terahertz quantum cascade lasers
A wide variety of application areas are eagerly aiming at the development of novel sensing and imaging systems
exploiting the availability of quantum cascade laser (QCL) compact semiconductor sources emitting in the mid-infrared
and terahertz ranges. After reviewing the state-of-the-art in this fast growing field, I will present our recent
demonstration of quartz-enhanced photo-acoustic trace gas sensors based on THz QCLs. Also, I will illustrate our
theoretical and experimental results on the coherent multimode dynamics of QCLs and their intrinsic stability under
strong optical feedback, showing examples of exploitations in the field of self-mixing interferometry and the
development of a novel detectorless contact-free imaging method to monitor the free electron density in semiconductor
| 12 febbraio
Dipartimento di Fisica, Università di Napoli Federico II
Role of thermal boundary resistance effects in superconducting cavities for particle accelerators
New generation of accelerators require increasing superconducting cavity performances. Kapitza thermal resistance
and, more in general, thermal boundary resistance effects have been often considered as a possible source of "non-ideal"
cavity behavior, through the formation of a temperature difference between the inner cavity superconducting surface and
the helium bath. However the general assessment reported in the literature is that such effects can be generally
neglected, at least at low or moderate input power.
Here we present new data on small test 6Ghz cavities, showing new evidence of the relevance of thermal effects.
Routes for lowering the Kapitza resistance and to improve the overall cavity performances are finally discussed.
| 5 febbraio
L'Istituto Nazionale di Ricerca Metrologica (INRIM): una presentazione
| 3 febbraio
Induzione Elettromagnetica, un fenomeno semplice... ma non banale
(Storia, curiosità, paradossi, formulazioni ed interpretazioni attorno alla legge di Faraday)
Scoperta da Faraday (e, pressoché contemporaneamente, da Henry) nel 1831, l'induzione elettromagnetica
è il principio alla base di innumerevoli realizzazioni tecnologiche di uso comune.
A dispetto di tale versatilità applicativa, la rappresentazione modellistica di questo fenomeno è
tuttavia apparsa critica fin dagli albori dell'elettrotecnica, come testimoniato dai vari esempi di "paradossi"
che sembrano smentire la validità della legge usata per descriverlo.
Nel corso del seminario si discuteranno alcuni di questi paradossi, insieme agli approcci che sono stati proposti
per risolverli, nonché alle più recenti revisioni del problema, atte ad individuare una sua
formulazione dall'efficacia generale.
Infine saranno proposte riflessioni sull'interpretazione causale dell'induzione elettromagnetica,
che ne costituisce un ulteriore aspetto sfuggente. L'intera presentazione sarà scandita da citazioni
tratte direttamente dalle opere di alcuni dei "giganti" che hanno contribuito alla costruzione dell'Elettrodinamica Classica.
| 3 febbraio
Presidente Physikalisch-Technische Bundesanstalt (PTB)
Metrology and Light - in the Year of Light and Beyond
Metrology with and for light has been an ever-increasing field since the invention of the dynamo by
W. v. Siemens in 1866 and of the carbon filament lamp by T. A. Edison in 1879. The foundation of the
Physikalisch-Technische Reichsanstalt, PTR, in 1887 by H. v. Helmholtz and W. v. Siemens was among
others strongly driven by the enormous growth of electric and lighting technologies in those days.
Today we are facing a second revolution in light and lighting technologies with innovative laser-,
LED- and OLED-source developments, the evolution of nano-photonics, single-photon and quantum-information
technologies to name just a view with the quest for state-of-the-art metrology. In the future, light
will play an even more important role for metrology with the advent of optical clocks, broad-band and
high-precision optical fibre transmission technologies, methods to achieve spatial resolutions below
the Abbe limit, with attosecond and free-electron-laser light sources coming online.
In the talk the fascination of light for mankind, the development of light and lightening technologies
as well as present and future developments will be highlighted emphasizing in particular the challenges
and opportunities for metrology in the future.
| 28 gennaio
Università degli Studi di Trieste
Synergies between Chemistry and Nanotechnology: Applications to Neurosciences and Energy
Many problems of our times have not been solved yet, mostly due to the complexity of the
problems and their difficult solutions. New approaches and new materials are therefore needed,
to produce breakthroughs and generate new hopes. Among the wide range of novel materials
available today, carbon nanotubes (CNTs) and graphene stand as unique materials for fundamental
research and potential applications. During this talk, we will report on the most recent advances
in our group, which have led to several interesting applications in many fields. For instance,
functionalized carbon nanotubes stimulate neuronal communication or can serve as carriers for
innovative drug delivery systems. On the other hand, carbon nanotubes and graphene are ideal
supports for catalysis in water splitting devices, for the production of hydrogen as a clean
source of energy.