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Lundi 29 Septembre 2014 à 10h30 : soutenance de thèse de Julien Frougier

Julien Frougier soutiendra sa thèse intitulée "Towards Spin-LEDs and Spin-VECSELs operations at magnetic remanence" à l’auditorium de Thales-RT.

 

 

cnrs thalesSeptember 2014

Sub-nanometer Atomic Layer Deposition for Spintronics in Magnetic Tunnel Junctions Based on Graphene Spin-Filtering Membranes
M.B. Martin et al., ACS Nano, 8 7890 (2014)

We report on the successful integration of low-cost, conformal, and versatile atomic layer deposited (ALD) dielectric in Ni-Al2O3-Co magnetic tunnel junctions where the Ni is coated with a spin-filtering graphene membrane. The ALD tunnel barriers, as thin as 0.6 nm, are grown layer-by-layer in a simple, low-vacuum, ozone-based process, which yields high-quality electron-transport barriers as revealed by tunneling characterization. Even under these relaxed conditions, including air exposure of the interfaces, a significant tunnel magnetoresistance is measured highlighting the robustness of the process. The spin-filtering effect of graphene is enhanced, leading to an almost fully inversed spin polarization for the Ni electrode of -42%. This unlocks the potential of ALD for spintronics with conformal, layer-by-layer control of tunnel barriers in magnetic tunnel junctions toward low-cost fabrication and down-scaling of tunnel resistances.

 

 

cnrs thalesAugust 2014

Freezing and thawing of artificial ice by thermal switching of geometric frustration in magnetic flux lattices
J. Trastoy et al., Nature Nanotechnology (2014)

Using a masked ion irradiation technique that allows us to nanopattern the electronic properties of oxides, we experimentally realize a system in which the geometry of the potential-energy landscape for magnetic flux quanta (vortices) can be switched using temperature as the control knob. Depending on the temperature, the flux quanta induced by an applied magnetic field see either a geometrically frustrated energy landscape that favours an ice-like flux ordering, or an unfrustrated landscape that yields a periodic flux distribution. This effect is reflected in a dramatic change in the superconductor’s magneto-transport. The thermal switching of the energy landscape geometry provides a model for the study of ordering and reorganization in repulsive particle manifolds.

 

 

cnrs thales

Mercredi 16 juillet à 14h00 : soutenance de thèse de Marta Galbiati

Marta Galbiati soutiendra sa thèse intitulée "Molecular Spintronics: from Organic Semiconductors to Self-Assembled Monolayers" à l’auditorium de Thales-RT.

 

 

cnrs thalesJuly 2014

Suppression of the critical thickness threshold for conductivity at the LaAlO3/SrTiO3 interface
E. Lesne et al., Nature Communications 5, 4291 (2014)

In epitaxial heterostructures of metal oxides, charge reconstruction at interfaces may produce electronic states different from those of the bulk constituents. A prototypical example of such interface system is LaAlO3/SrTiO3: both materials are band insulators but a high-mobility metallic state (two-dimensional electron gas) can appear at the interface if the thickness of the LaAlO3 film grown onto SrTiO3 exceeds four unit cells. The existence of this critical thickness threshold has been reproducibly found by dozens of groups worldwide. Remarkably, we have found that the two-dimensional electron gas can in fact appear at the interface for an LaAlO3 thickness of only one unit-cell if a metallic layer (here cobalt) is deposited onto the LaAlO3.

 

 

cnrs thalesApril 8-11, 2014

SKYMAG 2014, Paris, France

The workshop aims to gather researchers from different disciplines (magnetism, spintronics, surface science, neutron scattering, synchrotron techniques, ...) for stimulating fruitful discussions and defining future directions for magnetic skyrmions. SKYMAG workshop wilwill be held between April 9-11, 2014, on the campus of Chimie ParisTech, which is located in the Latin Quarter at the heart of Paris.

Workshop web site

 

 

cnrs thalesFebruary 2014

Electric-field control of magnetic order above room temperature
R. O. Cherifi et al., Nature Materials (2014)

In collaboration with teams from Université Paris-Sud, Ecole Centrale Paris, the University of Newcastle and the Helmholtz Zentrum Berlin, researchers from UMPhi have shown that a transition from an antiferromagnetic to a largely ferromagnetic state can be induced just above room temperature by applying a low electric field in heterostructures combining BaTiO3 and FeRh. The magnetization change is very large, corresponding to the largest magnetoelectric coupling ever reported. Structural data as well as first principles calculations indicate that the effect is mainly driven by voltage-dependent strain from BaTiO3. These results highlight the relevance of hybrid multiferroics combining oxides and transition metal alloys to achieve large, high temperature magnetoelectric effects.

Lire la suite

 

 

cnrs thalesDecember 2013

Spin-to-charge conversion using Rashba coupling
J. C. Rojas Sánchez et al., Nature Communications (2013)

The Rashba effect is an interaction between the spin and the momentum of electrons induced by the spin-orbit coupling (SOC) in surface or interface states. Its potential for conversion between charge and spin currents has been theoretically predicted but never clearly demonstrated for surfaces or interfaces of metals. Here we present experiments evidencing a large spin-charge conversion by the Bi/Ag Rashba interface. This result demonstrates that the Rashba effect at interfaces can be used for efficient charge-spin conversion in spintronics.

 

 

cnrs thalesOctober 2013

The ultimate storage bit : a magnetic skyrmion
J. Sampaio et al., Nature Nanotechnology (2013)

Researchers from the Unité Mixte de Physique CNRS/Thales and the Laboratoire de Physiques des Solides have shown by micromagnetic simulations which are the conditions for the stability of isolated skyrmions or chains of skyrmions in magnetic films and especially how these skyrmions can be nucleated experimentally by a strong spin current local injection. We also show how to move effectively isolated skyrmions or chains of skyrmions along nanostripes by an electrical current and detected by a magnetoresistive effect. Our results clearly define a way forward for the use of skyrmions in innovative storage devices or information processing.

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26 Juin 2013

Prix LAZARE-CARNOT 2013

Vincent Cros, directeur de recherches au CNRS, est le lauréat 2013 du Grand Prix Lazare-Carnot de l'Académie des sciences.

 

 

June 2013

Crafting the magnonic and spintronic response of BiFeO3 films by epitaxial strain
D. Sando et al., Nature Materials 12, 641 (2013)

Multiferroics are compounds that show ferroelectricity and magnetism. Here we bring insight into the rich spin physics of BiFeO3 in a detailed study of the static and dynamic magnetic response of strain-engineered films. We reveal that strain progressively drives the average spin angle from in-plane to out-of-plane, a property we use to tune the exchange bias and giant-magnetoresistive response of spin valves.

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Mercredi 26 juin à 14h30: Habilitation à diriger des recherches

Julie Grollier , soutiendra son habilitation à diriger des recherches "From Spin Torque Nano-Oscillators to Memristors: Multi-Functional Nanodevices for Advanced Computing” à l’auditorium de Thales TRT.

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Mars 2013 : deux prix à l'unité mixte de physique CNRS/Thales

  

Olivier d'Allivy Kelly, doctorant au laboratoire, a reçu un prix du meilleur poster au Colloque Louis Néel 2013 pour sa contribution intitulée « Dépendance en épaisseur de l’effet Hall de spin inverse dans un système ultramince YIG(7-20nm)/Pt »

  

Manuel Bibes, chargé de recherches au CNRS, vient de se voir décerner le EU-40 Materials Prize par l’European Materials Research Society (E-MRS)

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March 2013 :

Skyrmions on the track
Albert Fert, Vincent Cros and João Sampaio, Nature Nanotechnology 8, 152 (2013)

 

Magnetic skyrmions are nanoscale spin configurations that hold promise as information carriers in ultra-dense memory and logic devices due to the extremely low spin-polarized currents needed to move them.

 

 

Deux prix de thèse au laboratoire en 2012

Arnaud Crassous a été récompensé par le prix Sciences Aguirre-Basualdo de la Chancellerie pour ses travaux intitulés "Contribution à l'étude des effets de champ à l'échelle nanométrique dans des hétérostructures d'oxydes", sous la direction d’Agnès Barthélémy et Javier Villegas.

Antoine Dussaux est lauréat du prix Jeune Chercheur Daniel Guinier de la Société Française de Physique pour son travail de thèse intitulé "Etude des oscillations de vortex magnétiques induites par transfert de spin", sous la direction de Vincent Cros et Julie Grollier.

 

 

cnrs thalesOctober 2012

Self-assembled monolayers reveal their potential for molecular spintronics
Marta Galbiati, Clément Barraud, Sergio Tatay et al.,
ACS Nano (2012) &
Advanced Materials (2012)

(La,Sr)MnO3 manganite (LSMO) has emerged as the standard ferromagnetic electrode in organic spintronic devices due to its high spin-polarization and air stability. Whereas organic semiconductors and polymers have been mainly envisaged to propagate spin information, self-assembled monolayers (SAMs) have been overlooked and should be considered as promising materials for molecular engineering of spintronic devices. In this way dodecyl and octadecyl phosphonic acids SAMs have been grafted over the LSMO half-metallic oxide. Alkylphosphonic acids form ordered self-assembled monolayers with the phosphonic group coordinated to the surface.

Molecular magnetic tunnel junctions using these SAMs as tunnel barriers show stable and efficient spin transport properties. Large tunnel magnetoresistance with a flat bias voltage dependence of the magnetoresistance is observed in LSMO/dodecylphosphonic acid SAM/Co nanocontacts. This opens the door to spintronic tailoring though SAM engineering and could also lead to new venues for spin injection in organic devices.

 

 

21 september 2012

A ferroelectric memristor
A. Chanthbouala, et al., Nature Materials (2012)

Memristors are continuously tunable resistors that emulate biological synapses. Conceptualized in the 1970s, they traditionally operate by voltage-induced displacements of matter, although the details of the mechanism remain under debate. Purely electronic memristors based on well-established physical phenomena with albeit modest resistance changes have also emerged. In collaboration with scientists from the University of Cambridge and Thales Research and Technology, researchers from the Unité Mixte de Physique CNRS/Thales have just demonstrated that voltage-controlled domain configurations in ferroelectric tunnel barriers yield memristive behaviour with resistance variations exceeding two orders of magnitude and a 10 ns operation speed. Using models of ferroelectric-domain nucleation and growth, they explain the quasi-continuous resistance variations and derive a simple analytical expression for the memristive effect. The results suggest new opportunities for ferroelectrics as the hardware basis of future neuromorphic computational architectures.

Lire la suite (en français)

 

 

08 July 2012

Commensurability and chaos in magnetic vortex oscillations
S. Petit-Watelot, et al., Nature Physics(2012)

Researchers at the Institute of Fundamental Electronics (CNRS / Univ. Paris-Sud) and the Unité Mixte de Physique CNRS/Thales, in collaboration with teams at City University of Hong Kong and the University of Ghent (Belgium), just highlight a phenomenon of self-modulation - and even chaotic phases - in the dynamic of magnetic vortex core, that is the central area of a few tens of nanometers in the center of the vortex. This work, which opens new perspectives on nanoscale microwave oscillators for secured communications.

Lire la suite (en français)

 

 

03 june 2012

Highly efficient spin transport in epitaxial graphene on SiC
B. Dlubak et al., Nature Physics (2012)

Spin information processing is a possible new paradigm for post-CMOS electronics and efficient spin propagation over long distances is fundamental to this vision. However, despite several decades of intense research, a suitable platform is still wanting. We report here on highly efficient spin transport in two-terminal polarizer/analyser devices based on high-mobility epitaxial graphene grown on silicon carbide. Taking advantage of high-impedance injecting/detecting tunnel junctions, we show spin transport efficiencies up to 75%, spin signals in the mega-ohm range and spin diffusion lengths exceeding 100 µm. This enables spintronics in complex structures: devices and network architectures relying on spin information processing, well beyond present spintronics applications, can now be foreseen.

Lire la suite (en français)

 

 

22 may 2012

Gate-controlled spin injection at the LaAlO3/SrTiO3 interface
N. Reyren et al, Phys. Rev. Lett. 108, 186802 (2012)

The electrical Hanle (Voight geometry) and Inverse Hanle (Faraday geometry) effect in a three-point geometry have been used to probe the electrical spin injection, at low temperature, at the direct LaAlO3/SrTiO3 (LAO/STO) interface from a ferromagnetic Co reservoir. The significant drop of the electrical voltage (or resistance) obtained, its very high amplification compared to the classical theory of spin injection/relaxation and the corresponding variation of the electrical spin signal upon back-gate action emphasize a preferential resonant spin injection mechanism into localized states strongly coupled to the electronic two-dimensional electron system (2-DES) in STO. A detailed analysis of our data shows that spin can be conserved from the localized states to the 2-DES by tunnelling transfer evidencing, for the first time, an efficient electrical spin injection into an oxide 2-DES.

 

 

14 may 2012

Equal-spin Andreev reflection at high-temperature superconductor/half-metal interfaces
C. Visani et al., Nature Physics (2012)

The penetration of a superconducting current from a superconductor into a half-metallic ferromagnet is forbidden in the conventional picture of the proximity effect. However, we found resonances in the conductance spectra of superconductor/half-metal heterostructures that suggest the occurrence of unconventional equal-spin Andreev reflection, which allows for the generation and propagation of high-temperature superconducting spin currents into the half-metal. This mechanism may open the door to novel spintronic devices.

 

 

9 December 2011

Ferroelectric manipulation of magnetic flux quanta
A. Crassous et al., Phys. Rev. Lett. 107, 247002 (2011)

Using heterostructures that combine a large-polarization ferroelectric and a high-temperature superconductor, we demonstrate the nanoscale modulation of the superconducting condensate via ferroelectric field effects. Through this mechanism, a nanoscale pattern of normal regions that mimics the ferroelectric domain structure can be created in the superconductor. This yields an energy landscape for magnetic flux quanta and, in turn, couples the local ferroelectric polarization to the local magnetic induction. We show that this form of magnetoelectric coupling, together with the possibility to reversibly design the ferroelectric domain structure, opens the door to a new class of reconfigurable superconducting nano-devices.

 

 

December 14-16, 2011

Spin Master Voice workshop 2011,
Château de Villiers le Mahieu, France

The AIMS of the Spin Master Voice workshop, co-organized by the Unité Mixte de Physique CNRS/Thales and the Service de Physique de l'Etat Condensé (CEA, Saclay) , are to bring together scientists and engineers interested in recent trends and developments of spin transfer mechanisms in magnetic hybrid nano-structures. The goals are to identify the experimental and theoretical opportunities of these devices as novel microwave components, the breakthroughs that are required to enhance their properties (i.e. emission power, phase noise, tunability and rf sensitivity) as well as the associated challenges in the development of advanced characterization spectroscopy.

  

Website: Spin Master Voice 2011

 

 

04 december 2011

Solid-state memories based on ferroelectric tunnel junctions
A. Chanthbouala, A. Crassous et al., Nature Nanotechnology (2011)

We report non-volatile memories with OFF/ON ratios as high as 100 and write powers as low as ~ 104 A/cm2 at room temperature by storing data in the electric polarization direction of a ferroelectric tunnel barrier. The junctions show large, stable, reproducible and reliable tunnel electroresistance, with resistance switching occurring at the coercive voltage of ferroelectric switching. These ferroelectric devices emerge as an alternative to other resistive memories, and have the advantage of not being based on voltage-induced migration of matter at the nanoscale, but on a purely electronic mechanism.

 

 

21 august 2011

A new approach for creating room-temperature multiferroics,
S. Valencia, A. Crassous et al., Nature Materials (2011)

Multiferroic materials possess two or more ferroic orders but have not been exploited in devices owing to the scarcity of room-temperature examples. Those that are ferromagnetic and ferroelectric have potential applications in multi-state data storage if the ferroic orders switch independently, or in electric-field controlled spintronics if the magnetoelectric coupling is strong. It is shown that, at the interface with Fe or Co, the archetypal ferroelectric BaTiO3 simultaneously possess a magnetization and a polarization that are both spontaneous and hysteretic at room temperature. Ab initio calculations of realistic interface structures provide insight into the origin of the induced moments and bring support to this new approach for creating room-temperature multiferroics.

 

 

10 April 2011

Vertical-current-induced domain-wall motion in MgO-based magnetic tunnel junctions with low current densities, A. Chanthbouala et al., Nature Physics (2011)

In the past few years, there have been a number of proposals for fabricating magnetic memories based on the current-induced motion of magnetic domain walls. A device that uses a novel geometry for injecting electrical currents into the sample is shown to work with current densities that are two orders of magnitude lower than in previous approaches.

 

 

7 mars 2011

Journée thématique : "Memristor : Composants et Architectures"

L'unité Mixte de Physique CNRS/Thales organise une journée thématique sur les memristor (composants et archtectures) le lundi 7 mars 2011 à l'auditorium du centre de recherche Thales Research and Technology.

Vous pouvez vous inscrire auprès de Julie Grollier; Programme de la Journée

 

 

12 janvier 2011

Microélectronique : un gaz d'électrons à la surface d'un isolant ouvre la voie du transistor multi-fonctions

Des chercheurs du CNRS et de l'Université Paris-Sud 11 ont découvert comment créer une couche conductrice à la surface d'un matériau isolant et transparent très étudié pour la microélectronique du futur, le titanate de strontium (SrTiO3).

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15 octobre 2010 :

Pierre Séneor, membre junior de l'IUF

Pierre Séneor, enseignant chercheur de l'Université Paris-Sud 11, a été nommé à l'Institut universitaire de France à titre de membre junior.

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30 juillet 2010

Agnès Barthélémy, médaille d'argent 2010,

Agnès Barthélémy, professeur à l'Université Paris Sud 11 et membre senior de l'Institut Universitaire de France est lauréate de la médaille d'argent 2010 du CNRS.

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7 juillet 2010

Julie Grollier, Prix Jacques Herbrand 2010

Julie Grollier, chargée de recherches CNRS au laboratoire, est la lauréate 2010 du Prix Jacques Herbrand de l'Académie des sciences.

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Research activities


Spintronics and Nanomagnetism

L’Unité Mixte de Physique, après avoir été un acteur majeur de l’éclosion et du développement de la spintronique, est aujourd’hui présente dans la plupart des développements actuels en spintronique et nanomagnétisme.

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HTC Superconducters and Signal Processing

This research line concern the study of high superconducting materials (HTSC) and related materials, and their application in the microwave domain.

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Functional Oxides

Cet axe de recherche est né de notre volonté de coordonner nos activités croissance, étude des propriétés structurales et étude des propriétés d’interface, dont le but commun est la réalisation d’hétérostructures fonctionnelles d’oxydes.

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Materials and Nanotechnologies

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Microfabrication LIGA

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Seminar schedule

  

Albert Fert and the Nobel Prize in Physics 2007

A new field in science and technology : the spintronics

  

Albert Fert and Peter Grünberg are well-known for having opened a new route in science and technology by their discovery of the Giant MagnetoResistance (GMR) in 1988. Soon after this discovery, the exploitation of the GMR had a considerable impact in data storage technologies.

  

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Le lundi 15 décembre 2008, Albert Fert a donné au Palais de la Découverte une conférence intitulée «Spintronique : le spin des électrons s’invite dans nos ordinateurs et nos téléphones ! » . Vous pouvez écouter cette conférence sur le site du Palais de la Découverte.

Unité Mixte de Physique CNRS/Thales

  

1, avenue Augustin Fresnel

91767 Palaiseau Cedex

Tel: 01 69 41 58 79 / 01 69 41 56 47

Fax: 01 69 41 58 78

  

 

 

Unité Mixte de Physique CNRS/Thales (UMR 137)

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