• Document: Individual skyrmions at room temperature From magnetic thin films to magnetic multilayers
  • Size: 2.62 MB
  • Uploaded: 2018-12-07 10:11:08
  • Status: Successfully converted


Some snippets from your converted document:

Individual skyrmions at room temperature From magnetic thin films to magnetic multilayers V. CROS1, C. MOREAU-LUCHAIRE1, C. MOUTAFIS2,*, N. REYREN1, J. SAMPAIO1,*, C.A.F. VAZ2, P. WARNICKE2, D. MACCARIELLO1, N. VANHORNE1, F. GARCIA-SANCHEZ3, K. BOUZEHOUANE1, K. GARCIA1, C. DERANLOT1,S. ROHART4, J.M. GEORGE1, J. RAABE2, M. WEIGAND5, J.V. KIM3, A. THIAVILLE4, A. FERT1 1 Unité Mixte de Physique CNRS/Thales and Université Paris Sud, Palaiseau, France 2 Swiss Light Source, Paul Scherrer Institute, Villigen, Switzerland * University of Manchester, UK 3 Institut d’Electronique Fondamentale, Université Paris Sud, CNRS, Orsay, France 4 Lab. de Physique des Solides, CNRS, Université Paris Sud, Orsay, France 5 Max Planck Institute for Intelligent Systems, Stuttgart, Germany Why to investigate magnetic skyrmions in spintronics? Courtesy : K. Evershor Skyrmion is a topological soliton with a spin texture covering continuously all spin directions Main characteristics of magnetic skyrmions :  Skyrmions have nanoscale and tuneable dimensions : higher level of integration  Skyrmions cannot be bent into a uniform state : improved protection against defects  Skyrmions can displace by spin torque : motion of arrays of skyrmions at very low current densities ~ 105A/cm² Review paper by N. Nagaosa, Y. Tokura, Nature Nanotech. 8, 899 (2013) SOCSIS 2015 – ICFM, Workshop Spetses, Greece2011/10/03 Partenit– – June 10, 2015 2 Interfacial Dzyaloshinskii-Moriya interaction 1) Break of the inversion symmetry at the interface 2) Large spin orbit coupling in the normal metal (i.e. large Dzyaloshinskii-Moriya interaction DMI) Hedgehog skyrmion In case of interfacial DMI : A. Fert, Mater. Sci. Forum 59, 439 (1990)  Main advantages : multiple possible associations of magnetic thin films and metals with large SO coupling (Pt, Ir, W etc…) in bilayers or multilayers  Opportunities to tune various parameters : DMI (dilution with thickness), magnetic anisotropy (ion bombardement), number of active interfaces etc… SOCSIS 2015 – ICFM, Workshop Spetses, Greece2011/10/03 Partenit– – June 10, 2015 3 Nano-skyrmion lattice Spin Polarized STM experiments on 1 ML Fe on Ir (111) ∼ 1 nn S. Heinze et al, Nature Phys. 7, 713 (2011)  First experimental observation of skyrmion lattice in ultrathin film  Very large DMI : D/J ∼ 0.3  Stabilization of nanoskyrmion even at zero field SOCSIS 2015 – ICFM, Workshop Spetses, Greece2011/10/03 Partenit– – June 10, 2015 4 Numerical simulations of the stabilization, the nucleation, the propagation and the excitation of individual skyrmions in magnetic nanostructures J. Sampaio, VC et al, Nature Nanotech 8, 839 (2013) A. Fert, VC et al, Nature Nanotech 8, 135 (2013) J.V. Kim, VC et al Phys. Rev. B, 09, 064410 (2014) SOCSIS 2015 – ICFM, Workshop Spetses, Greece2011/10/03 Partenit– – June 10, 2015 5 Skyrmions in magnetic nanostructures Main interests to stabilize magnetic skyrmions in nanostructures  Individual skyrmions can be stabilized in magnetic dots or strips  Nucleation of skyrmion can be done through spin injection  Vibrating or oscillating modes of skyrmions can be excited  They can be easily moved by spin transfer torques  Micromagnetic simulations with adapted OOMMF code for thin magnetic films in nanostructures such as disks or stripes : ε = εEXCH + εDM + εK + εDIPOLAR skyrmions TOP with D in J/m2 ∝ D12/t Parameters for Pt/Co 0.4 nm • MS = 580 kA/m2 Co • KU = 0.8 MJ/m3 SIDE strong SOC Pt

Recently converted files (publicly available):