Spin-orbit technologies: Memory switching to THz generation


  • Datum: 14.09.2018
  • Uhrzeit: 11:00
  • Vortragende(r): Prof. Hyunsoo Yang
  • Department of Electrical and Computer Engineering, National University of Singapore
  • Ort: Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle (Saale)
  • Raum: Lecture Hall, B.1.11
Spin-orbit technologies: Memory switching to THz generation

Current induced spin-orbit torques (SOTs) provide a new way to manipulate the magnetization. We first try to understand various spin textures. In order to probe spin textures, we utilize the bilinear magnetoelectric resistance, photovoltage microscopy for topological insulators, and Lorentz transmission electron microscopy for imaging of chiral spin textures, skyrmions in an exchange-coupled Co/Pd multilayer.

We then utilize those spin textures for magnetization switching. We find that a full sign reversal of SOTs occurs as the oxygen bonding increases in Pt/CoFeB/MgO, which evidences an interfacial SOT mechanism. We show much enhanced current induced SOTs from Co/Pd multilayers, ferrimagnetic CoGd systems, a topological insulator Bi2Se3 as well as an oxide heterostructure SrTiO3/LaAlO3, which generate strong spin currents to switch the magnetization. In order to understand detailed switching SOT switching mechanism, time resolved SOT spin dynamics is probed, and oscillatory SOT switching induced by eld-like torques is measured. We propose a eld-free SOT switching scheme using one domain wall motion in an anti-notch structure. Finally, we discuss the generation of THz for heavy metal/ferromagnet structures using SOTs.

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