Current-induced dynamical tilting of chiral domain walls in curved microwires

Abstract

This is a repository copy of Current-induced dynamical tilting of chiral domain walls in curved microwires.

Ice nucleation imaged with X-ray spectro-microscopy

“…A li-off step was performed by immersing the patterned membrane in pure acetone to remove the resist and extraneous platinum over layer, but retaining the platinum wire pattern. Contacts extended from the membrane to the supporting silicon frame and were wire bonded (TPT HB05) to a custom printed circuit board 102,105 connected to a high precision electrometer (Keithley Series 4200). The sensor resistance was around 600 U at room temperature and a sample specic temperature calibration, described in a later section, was performed.…”

Domain wall motion at low current density in a synthetic antiferromagnet nanowire

“…To compare the results we have obtained here on DWs in SAF multilayers we have performed a meta-analysis on prior work on STXM imaging of current-driven DW motion in conventional multilayers based around a Pt/CoB/Ir repeat unit that have a FM-aligned ground state [18][19][20] . Data points obtained from those previous works are also plotted in Fig.…”

Time-resolved visualization of the magnetization canting induced by field-like spin–orbit torques

“…5, it is then possible to estimate, using a coherent rotation model [20], the effective field generated by the FL-SOT that would result in such a canting of the magnetization. Utilizing a value of 1.14 MA m −1 for the saturation magnetization and of 600 kJ m −3 for the perpendicular magnetic anisotropy for the Pt/CoB/Ir multilayer presented here [17], an effective field of 26±6 mT for the FL-SOT at an injected current density of 7.5 × 10 11 A m −2 can be calculated. This value is consistent with the values for the FL-SOT effective magnetic field determined for other material systems using electrical transport measurement techniques [21], providing another indication of the applicability of TR-STXM for the investigation of SOT processes.…”

“…A schematic overview of the sample, along with an overview of the electrical setup employed for its excitation, is shown in Fig.2. More details about the fabrication processes used for the samples reported here are given in Refs [15][16][17]…”

“…(1), the Pt/CoB/Ir microwire was initialized in a bi-domain state by the injection of a 4 ns long, 350 mA current pulse across the Cu stripline shown in Fig.2. The time-resolved measurements were then performed with the following protocol, which guaranteed the reproducibility of the dynamical processes necessary for pump-probe measurements: (i) a 20 ns long current pulse with a current density of 7.5 × 10 11 A m −2 was injected across the Pt/CoB/Ir microwire, causing the SOTinduced canting of the two PMA domains, and a current-induced motion of the domain wall (CIDWM) between the two PMA domains[15,17]; (ii) after 500 ns from the end of the first pulse, a 20 ns long current pulse with a current density of −7.5 × 10 11 A m −2 was injected across the Pt/CoB/Ir microwire, causing the SOT-induced canting of the two PMA domains (in the opposite direction with respect to (i)), and the CIDWM of the domain wall back to its original position; (iii) after 700 ns from the end of the second current pulse, a 4 ns long, 350 mA current pulse was injected across the Cu stripline. This pulse is injected to guarantee that the magnetic configuration is reset to the exact same state at each cycle.…”