www.thalesgroup.com YIG Magnonics Abdelmadjid Anane [email protected] Unité Mixte de Physique CNRS/Thales, Palaiseau et Université de Paris-Sud, Orsay, France. Spin based computation 2 / CMOS is one of the greatest achievement in human history buffer Spintronic computaion Non volatile logic operation Spintronic computaion CMOS interface underlayer Spintronics computational schemes Spin-FET (Datta & Das transistor) • Domain wall logic, Nanomagnet logic … • Pure spin current logique Neuromorphic computaion (spintronic synapses) Magnon electronics Spin based computation 3 / CMOS is one of the greatest achievement in human history buffer Spintronic computaion Non volatile logic operation Spintronic computaion CMOS interface underlayer Spintronics computational schemes A. Khitun et al. J. of Physics D (2010) Magnon electronics (spin waves) Other applications include rf electronics APL 87, 153501 2005 Kaiserslautern Onde de spin dans les materiaux ferromagnétiques Une onde de spin est une excitation collective des spin Magnons Lee K S and Kim S K 2008 J. Appl. Phys. 104 053909 VG ~ 105 m/s O ~ 10 - 100 nm •La relation de dispersion dépends des caractéristiques magnétiques du matériau et de sa géométrie et du champ appliqué. •L’onde de spin est le vecteur d’information le moins couteux en énergie Condensat de Bose Einstein Micromagnetisme des ondes de spin Excitation local et propagation DG est une constante du matériaux qui décrit la dissipation Pour le Py : D = 0.01 et la longueur d’atténuation est ~ 10 µm Relations de dispersion Traitement de l’information avec les spin wave (Beyond CMOS) Réalisation de portes logique sur le principe de l’interféromètre de Mach–Zehnder miniature NOT gate OR gate L’information est encodée par modulation de la phase de la SW AND gate Magnetic field Calcul parallel à base d’interférence de SW Magnetic Cellular Nonlinear Network nce d’ondes de spin Applications analogiques des SW : un peu d’histoire Sphère de YIG (Y3Fe5O12 ) , FMR Q0 = 10 000 Accordable de 0.5 Æ 40 GHz Ce que peut apporter l’électronique de Spin Filtres à base de SW Filtres actifs est amplification / atténuation de SW I>0 & § dm ¨ © dt & § dm ¨ © dt Utiliser le couple de transfert de spin pour Amplifier l’amplitude des SW sous le contact ou Atténuer l’amplitude des SW sous le contact · ¸ ¹ injec. · ¸ ¹ Heff & § dm · ¸ ¨ dt ¹ injec © I<0 4 Heff & § dm ¨ © dt m . · ¸ ¹D Quelques réalisations experimentales Magnonics 15 / Magnonics at the nanoscale Challenge : how to couple to a spin wave with a SCALABLE scheme ? It depends on the medium material If it is a metal (permalloy or Heusler alloy) STT for excitation and TMR for detection If it is a magnetic insulator SHE for excitation and ISHE for detection Spin Hall effect 16 / Electron diffusion with spin orbit interaction Factor of merit : spin Hall angle metal Au < 1% Pt 5% E-W 30% Spin Hall effect and inverse spin Hall effect 17 / SHE : convert charge current to spin current ISHE convert spin current to charge current Factor of merit : spin Hall angle metal Au < 1% Pt 5% E-W 30% 18 / YIG is the best medium for magnonics αYIG x YIG thikness 19 Direct SHE: damping compensation FMR while passing a large dc curent in the Pt layer YIG magnonics Pure spin current magnonics requires : Direct & Inverse spin Hall Effect VISHE Jc Large SOC metal YIG (insulator) Js spin transparent interface Ultrathin YIG films with low damping Js Energy efficiency, Compatibility with standard micro fabrication, scalability of the technology… MMM, Denver, November 4-8 2013 Micromagnetisme des ondes de spin Excitation local et propagation buffer Spintronic Spintronic computaion computaion CMOS interface underlayer DG est une constante du matériaux qui décrit la dissipation Pour le Py : D = 0.01 et la longueur d’atténuation est ~ 10 µm Pour le YIG : D = 0.00001 et la longueur d’atténuation est ~ 1mm Pulsed laser deposition (PLD) 4 PLD deposition chambers : Manganites ZnO BiFeO3 SrTiO3 LaAlO3 BaTiO3 YBCO and many highTc SC ….. YIG Olivier d’ALLIVY KELLY, CNRS/THALES MMM, Denver, November 4-8 2013 PLD growth PLD parameters Laser Target Substrate Laser Nd:YAG 355nm Pulses repetition rate 2.5 Hz Substrate GGG (111) Target-substrate distance 44 mm O2 pressure 2.5 x 10-1 mbar Temperature 650°C A part from the laser there is no significant differences from the conditions used in Colorado State University by M. Wu and coll. Olivier d’ALLIVY KELLY, CNRS/THALES MMM, Denver, November 4-8 2013 24 / RHEED YIG(20nm)/GGG (111) Room Temperature. YIG(20nm)//GGG(111) Rotation(°) 10 295 Po2(mbar) ~.10-7 ~.10-7 RT RT T(°C) 24 Room temperature. 25 / RHEED YIG(20nm)/GGG 25 Substrate :(1) YIG :(2) YIG:(3) YIG(20nm)//GGG(111) AL4539 (1) (2) (3) Rotation(°) 267 342 342 Po2(mbar) 2.10-2 2,5.10-1 3,6.10-7 674 663 RT T(°C) 26 Characterization : X-ray diffraction No parasitic phases Lattice parameter: 27 Characterization : X-ray diffraction No parasitic phases 6 10 20 nm 7 nm 4 nm 104 102 100 118 120 118 120 2T degree 118 120 28 Characterization : AFM topography RMS roughness 4 nm 0.3 nm on 1µm2 7 nm 20 nm Rq = 0.3 nm Rq = 0.3 nm Rq = 0.1 nm Rq = 0.5 nm Rq = 0.5 nm Rq = 0.2 nm 29 Characterization : SQUID magnetometry Ultra soft nanometer-thick YIG 10 nm T = 300K 30 Characterization : SQUID magnetometry Ultra soft nanometer-thick YIG -20 2500 2000 -15 -10 -5 0 5 10 15 bulk 20 2500 2000 4 SMsYIG : 1750 G 1500 1500 1000 1000 500 500 0 0 -500 -500 -1000 -1000 4 nm 7 nm 15 nm 200 nm -1500 -2000 -2500 -20 -15 -10 -5 0 5 Magnetic Field (Oe) 10 15 -1500 -2000 -2500 20 31 Characterization : Ferromagnetic resonance Narrow FMR linewidth 32 Characterization : Ferromagnetic resonance Narrow FMR linewidth ; 33 Characterization : Ferromagnetic resonance Spin mixing conductance 20 nm Pt/YIG / , / Surface preparation before Pt deposition : Ar/O2 plasma . ∙ . YIG , . ∙ . ↑↓ 34 Characterization : Ferromagnetic resonance Origin of of ΔH0 35 YIG nanostructures etching rate 20 nm YIG on GGG SIMS detection Ar Etch conditions : Angle : 30 deg. Beam intensity : 0.50 mA/ cm2 Acceleration voltage: 350 V 36 Toward nanostructures Extended Film Nanodisk 37 Toward nanostructures Extended Film Samples (300,500,700 nm) Nanodisk 38 Toward nanostructures Extended Film Samples (300,500,700 nm) Nanodisk MRFM Measurement 39 Ferromagnetic resonance on YIG nanodisks Extended Film Nanodisk 40 Ferromagnetic resonance on YIG nanodisks 41 Local FMR on nanodisks n=0 n=0 n=1 n=2 - discrete MRFM-spectra observed for YIG and YIG/Pt nanodiscs n=1 ISHE measurements : Experimental results 42 Experimental setup z x y 13 nm A. V. Chumak et al., Applied Physics Letters 100, 082405 (2012) 43 ISHE measurements : Experimental results z x y 44 ISHE measurements : Experimental results Thickness dependence of ISHE Coherent behaviour with: Y. Kajiwara et al., Nature 464, 262 (2010) 45 ISHE measurements : Experimental results Thickness dependence of ISHE ΔH=4.6 Oe ΔH=13 Oe ΔH=19 Oe Coherent behaviour with: Y. Kajiwara et al., Nature 464, 262 (2010) Conclusion 9 Detection of pure spin current by ISHE on 0.5nm Pd/YIG 9 No induced magnetism in Pd/YIG 9 Results that support SMR theory Todo list 9 Damping compensation on nanodisks 9 Measurements of group velocity Thanks to O. d’Allivy Kelly , V. Cros, P. Bortolotti and A. Fert R. Bernard, E. Jacquet and A. H. Molperces. In collaboration with : J. Ben Youssef Université de Bretagne Occidentale, LMB-CNRS, Brest, France. F. Wilhelm and A. Rogalev ID12 Beamline, (ESRF), Grenoble, France. M. Muñoz Instituto de Microelectronica de Madrid, Madrid, Spain. C. Hahn, G. de Loubens, V. Naletov, M. Viret and O. Klein CEA SPEC, Saclay France.
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