[19p-P06-1~50] 10 Spintronics and Magnetics (Poster)

English Presentation

[19p-P06-49] Effect of Pulse Duration on Domain Wall Motion in Ferrimagnetic GdFe Nanowires

〇(P)Mojtaba Mohammadi¹, Satoshi Sumi¹, Kenji Tanabe¹, Hiroyuki Awano¹ (1.Spintronics Laboratory, Toyota Technological Institute, Nagoya 468-8511, Japan)

Keywords:

Racetrack Memory (RM),Ferrimagnetic GdFe Nanowires,Current-Induced Domain Wall Motion (CIDWM)

The advancement of low-energy memory devices necessitates the exploration of novel materials and fabrication techniques [1,2]. Here, we report on the fabrication and characterization of nanowires composed of ferrimagnetic GdFe thin films, deposited on a naturally oxidized Pt sublayer, and with a SiN protective layer. Utilizing electron-beam lithography and a lift-off method, we successfully fabricated nanowires with a width of 1μm. The primary focus of this study was to investigate the domain wall motion (DWM) within these nanowires under the application of voltage pulses of varying durations (1, 3, 5, 10, 20, and 30 ns). Our measurements revealed that the maximum DW velocity of around 1800 m/s was achieved with a 1 ns pulse duration. This high velocity is attributed to the effective spin-orbit torque (SOT) induced by the Pt under-layer, which enhances the efficiency of current-driven DWM. Notably, the current threshold for initiating DWM was approximately 7 × 10¹⁰ A/m². The presence of the Pt under-layer is crucial in achieving this low current threshold, as it promotes a strong spin Hall effect, thereby increasing the spin current density and reducing the required charge current. Interestingly, our results demonstrated that while DW velocity generally increases with current density, a deviation occurs for pulse durations of 20 ns and 30 ns. In these cases, the DW velocity increases with current density up to a maximum point, beyond which further increases in current density result in a decrease in velocity. This phenomenon may be attributed to the onset of the Joule heating effect [3] that impedes DWM at higher current densities over longer pulse durations. The results of this study demonstrate the feasibility of using ferrimagnetic GdFe nanowires, coupled with a Pt under-layer, for high-speed, low-energy memory applications.