A5029488412- Magnetic properties of thin films
- Magnetic Properties and Applications
- Theoretical and Computational Physics
- Physics of Superconductivity and Magnetism
- Magnetic Properties of Alloys
- Magnetic and transport properties of perovskites and related materials
- Ion-surface interactions and analysis
- Characterization and Applications of Magnetic Nanoparticles
- Magneto-Optical Properties and Applications
- Multiferroics and related materials
- Integrated Circuits and Semiconductor Failure Analysis
- Advanced Electron Microscopy Techniques and Applications
- Ferroelectric and Piezoelectric Materials
- Geomagnetism and Paleomagnetism Studies
- Advanced Condensed Matter Physics
- Semiconductor materials and interfaces
- Surface and Thin Film Phenomena
- Quantum and electron transport phenomena
- ZnO doping and properties
- Copper Interconnects and Reliability
- Metallic Glasses and Amorphous Alloys
- Radiation Detection and Scintillator Technologies
- Magnetic Properties and Synthesis of Ferrites
- Intermetallics and Advanced Alloy Properties
- Advanced Materials Characterization Techniques
Laboratoire de physique des Solides
2015-2024
Centre National de la Recherche Scientifique
2014-2023
Université Paris-Saclay
2004-2023
University of Leeds
2021
Université Paris-Sud
2010-2019
Université Paris Cité
2004
Laboratoire de Physique et d’Étude des Matériaux
2002
Schrodinger (United States)
2002
Université de Lorraine
1997-2001
University of Kaiserslautern
2000-2001
We report on magnetic domain-wall velocity measurements in ultrathin Pt/Co(0.5-0.8 nm)/Pt films with perpendicular anisotropy over a large range of applied fields. The complete velocity-field characteristics are obtained, enabling an examination the transition between thermally activated creep and viscous flow: motion regimes predicted from general theories for driven elastic interfaces weakly disordered media. dissipation limited flow regime is found to be consistent precessional motion,...
We report here that a Permalloy layer deposited on top of multiferroic BiFeO3 single crystal acquires an easy magnetic direction along the propagation vector cycloidal arrangement antiferromagnetic moments in BiFeO3. This anisotropy originates from direct coupling with canted spins forming cycloid. Moreover, we show electric field-induced change polarization is able to toggle ferromagnet through magnetoelectric effect, which links local
We present an analytical calculation of the velocity a single 180 degree domain wall in magnetic structure with reduced thickness and/or lateral dimension under combined action external applied field and electrical current. As for case field-induced propagation thick films, two motion regimes different mobilities are obtained, below far above so-called Walker field. Additionally, current induced motion, Walker-like density threshold can be defined. When dimensions system become comparable to...
The functional properties of oxide heterostructures ultimately rely on how the electronic and structural mismatches occurring at interfaces are accommodated by chosen materials combination. We discuss here LaMnO3/LaNiO3 heterostructures, which display an intrinsic interface asymmetry depending growth sequence. Using a variety synchrotron-based techniques, we show that degree intermixing monolayer scale allows interface-driven such as charge transfer induced magnetic moment in nickelate layer...
We report a comparative study of magnetic field driven domain wall motion in thin films made different materials for wide range and temperature. The full thermally activated creep motion, observed below the depinning threshold, is shown to be described by unique universal energy barrier function. Our findings should relevant other systems whose dynamics can modeled elastic interfaces moving on disordered landscapes.
Both the direction and strength of exchange bias field ${H}_{\mathrm{eb}}$ an FeNi/FeMn double layer are manipulated locally by He ion irradiation in applied magnetic field. The magnitude is enhanced over its initial value low dose regime. Above a threshold reduction eventually suppression found. initialized during irradiation. These observations discussed considering structural modifications caused bombardment. data well described model, which based on competition between enhancement due to...
Magnetization orientation in Ga${}^{+}$-irradiated Pt/Co(${d}_{\mathrm{Co}}$)/Pt ultrathin films can be changed a controlled way by adjusting the ion fluence, $F$. Two-dimensional (${d}_{\mathrm{Co}}$, $F$) diagrams of magnetic and magneto-optical properties have been derived. Distinct out-of-plane anisotropy states with enhanced effects were evidenced for specific values. This rich behavior originates from two competing mechanisms: intermixing Co Pt atoms at interfaces formation ordered...
We experimentally investigate the current-induced magnetization reversal in Pt/[Co/Ni]$_3$/Al multilayers combining anomalous Hall effect and magneto-optical Kerr techniques crossbar geometry. The occurs through nucleation propagation of a domain opposite polarity for current density order 0.3 TA/m$^2$. In these experiments we demonstrate full control each stage: i)the {\O}rsted field controls ii) domain-wall by spin torque from Pt effect. This scenario requires an in-plane magnetic to tune...
The effect of electrical current pulses on magnetic domain walls is studied in a nanometer-scale track defined ${\text{He}}^{+}$-irradiated Pt/Co(0.5 nm)/Pt film with out-of-plane anisotropy. Current wide range intensities and durations are shown to result either demagnetization, or polarity-independent domain-wall propagation, due Joule heating during the pulse. None expected spin transfer effects occur. To explain this, spin-dependent current-density distribution stack evaluated, frame an...
In ferromagnetic materials, the rich dynamics of magnetic domain walls (DWs) under a field or current has been successfully described using well-known $q\ensuremath{-}\ensuremath{\varphi}$ analytical model. We demonstrate here that this simple unidimensional model holds for multiple-sublattice materials such as ferrimagnetic alloys synthetic antiferromagnets (SAFs) by effective parameters, and it is in excellent agreement with double-lattice micromagnetic simulations. obtain laws DW velocity...
We demonstrate that the effects of spin-orbit coupling and inversion asymmetry exist in a single $\mathrm{Gd}\text{\ensuremath{-}}\mathrm{Fe}\text{\ensuremath{-}}\mathrm{Co}$ ferrimagnetic layer, even without heavy-metal interface. use electric transport measurements to quantify torques. measure Dzyaloshinskii-Moriya interaction using Brillouin light-scattering measurement technique, we observe resulting chiral magnetic textures x-ray photoemission electron microscopy. attribute these...
Magnetic anisotropy and magnetization reversal phenomena are studied in Ga1−xMnxAs films grown on GaAs(001). From the azimuthal dependence of magneto-optical Kerr rotation magnetic linear dichroism, in-plane 〈100〉 directions unambiguously assigned as axes easy magnetization. The values cubic uniaxial anisotropies determined. Magnetization proceeds by noncoherent spin irreversible jumps formation 90° domains.
The motion of a magnetic domain wall in He-ion-irradiated Pt/Co(0.5 nm)/Pt ultrathin film was studied low applied fields. field dependence the velocity displays creep behaviour, consistently with critical slowing-down when tends to zero. We also show that is induced by large spin reversal avalanches andthat energy barrier increase d irectly linkedto avalanche size. This observation excellent agreement theory elastic manifolds moving weakly disordered medium.
The exchange coupling observed between a soft ferromagnetic layer and the antiferromagnetic multiferroic compound ${\text{BiFeO}}_{3}$ (BFO) is investigated. Results obtained on BFO ferroelectric multidomain films monodomain single crystals are compared. A significant interface occurs in two systems whose anisotropy however differs significantly. In thin film based heterostructures, measured twofold of FM imposed by magnetic field during deposition well accounted for using double macrospin...
$R{\mathrm{Fe}}_{2}(110)$ single-crystal films have been grown by molecular-beam epitaxy $(R={\mathrm{Y},\mathrm{}\mathrm{S}\mathrm{m},\mathrm{}\mathrm{G}\mathrm{d},\mathrm{}\mathrm{T}\mathrm{b},\mathrm{}\mathrm{Dy}}_{0.7}{\mathrm{Tb}}_{0.3},$ Dy, Er). The are strained compared to bulk compounds and both sign value of the strains explained with a model differential thermal contraction between film substrate. M\"ossbauer spectrometry macroscopic magnetization measurements demonstrate that...
Ion irradiation is an excellent tool to modify magnetic properties on the submicrometer scale, without modification of sample topography. We utilize this effect magnetically pattern exchange bias double layers using resist masks patterned by electron-beam lithography. through leads a lateral magnetization reversal behavior and allows one study as function field strength single sample. Results are presented macroscopic microscopic magneto-optic Kerr force microscopy, respectively.
The field-driven velocity of magnetic domain walls in nanostrips patterned (Co/Ni) multilayer films with perpendicular anisotropy is studied by magnetooptical microscopy. By applying fields up to 250 mT, two peculiar features are revealed, which beyond the simple one-dimensional model. First, above wall depinning, a plateau observed over 150 mT field range. Then, at large fields, an important increase occurs. Micromagnetic simulations reproduce this behaviour and underline nontrivial role...
We study the ultraslow domain-wall motion in ferromagnetic thin films driven by a weak magnetic field. Using time-resolved magneto-optical Kerr effect microscopy, we access to statistics of intermittent thermally activated jumps between deep metastable states. Our observations are consistent with existence creep avalanches: roughly independent clusters broad size and ignition waiting-time distributions, each one composed large number spatiotemporally correlated elementary events. Moreover,...
As a magnetic domain wall propagates under small fields through random potential, it roughens as result of weak collective pinning, known creep. Using Kerr microscopy, we report experimental evidence surprising deroughening pairs in the creep regime, 0.5 nm thick Co layer with perpendicular anisotropy. A bound state is found cases where two rough domains nucleated far away from one another and first growing action field eventually do not merge. The remain separated by strip unreversed...
An elegant route for tuning the magnetic anisotropy of ultrathin Co films by Ga+ ion irradiation is presented. The a Pt/Co(2.6 nm)/Pt film first changed from in-plane to out-of-plane uniform low dose at 30 keV. When increasing dose, second spin reorientation transition toward sample plane also evidenced. This could be way design nanowires with perpendicular anisotropy, embedded in an magnetized environment, either through mask or focused beam. Tentative explanations on origin these two...