講演情報
[16a-D61-3]Enhancement of SOT-driven domain wall motion in wide heavy metal width structure
〇(DC)Kim Dongryul1, Sooboem Lee1, Chun-Yeol You1 (1.DGIST)
キーワード：
Domain wall、Spin orbit torque、Logic devices
Magnetic domain wall devices such as a racetrack memory and a spin torque majority gate have attracted significant attention recent decades owing to their non-volatile and uniaxial anisotropic features. In these devices, logic states of ‘1’ or ‘0’ is described by domain polarities of ‘up’ or ‘down’. Furthermore, the velocity of the domain wall (DW) is directly related to the speed of information processing. Therefore, enhancement of DW velocity can improve the performance of magnetic domain wall devices. In this study, we improved mobility of spin–orbit torque (SOT)-driven domain wall motion by modifying a structure of ferromagnetic (FM) and heavy metal (HM) wires, where the bottom HM wire width is wider than the top FM wire.
Ta(3)/Pt(5)/Co(1.2)/Ta(2) (in nanometer unit) heterostructure which exhibits considerable Dzyaloshinskii–Moriya interaction and SOT is exploited for investigation of SOT-induced domain wall motion. We fabricated FM wires with various line widths from 2 to 20 μm. Unlike the conventional single FM wire, only the width of FM layer is modified with fixing the width of the underneath HM (shown in Fig.1(a)). DW mobility which is defined as the slope of DW velocity versus applied current density at each FM wire width was evaluated by using Kerr microscopy. Harmonic Hall measurement is also conducted in the same geometry to investigate efficiencies of SOT. Interestingly, as shown in Fig.2 (b), DW mobility and SOT efficiency decrease as the FM wire width increases, with similar trends. The detailed discussion will be given in the presentation.
Ta(3)/Pt(5)/Co(1.2)/Ta(2) (in nanometer unit) heterostructure which exhibits considerable Dzyaloshinskii–Moriya interaction and SOT is exploited for investigation of SOT-induced domain wall motion. We fabricated FM wires with various line widths from 2 to 20 μm. Unlike the conventional single FM wire, only the width of FM layer is modified with fixing the width of the underneath HM (shown in Fig.1(a)). DW mobility which is defined as the slope of DW velocity versus applied current density at each FM wire width was evaluated by using Kerr microscopy. Harmonic Hall measurement is also conducted in the same geometry to investigate efficiencies of SOT. Interestingly, as shown in Fig.2 (b), DW mobility and SOT efficiency decrease as the FM wire width increases, with similar trends. The detailed discussion will be given in the presentation.
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