Micromagnetic simulation of spin-transfer switching in a full-Heusler Co2FeAl0.5Si0.5 alloy spin-valve nanopillar

Abstract

Spacer layer thickness dependence of exchange coupling in Co-enriched Co-Mn-Si/Cr/Co-Mn-Si epitaxial trilayers J. Appl. Phys. 110, 113901 (2011) Magnetometry and transport data complement polarized neutron reflectometry in magnetic depth profiling J. Appl. Phys. 110, 103914 (2011) (001) FePt graded media with PtMn underlayers Appl. Phys. Lett. 99, 212504 (2011) High performance bulk metallic glass/carbon nanotube composite cathodes for electron field emission Appl. Phys. Lett. 99, 194104 (2011) Current-induced domain wall motion in permalloy nanowires with a rectangular cross-section J. Appl. Phys. 110, 093913 (2011) Additional information on J. Appl. Phys. We investigated the spin-transfer switching in a full-Heusler Co 2 FeAl 0.5 Si 0.5 alloy spin-valve nanopillar through micromagnetic simulation. A two-step switching hysteresis loop due to the fourfold in-plane magnetocrystalline anisotropy of Co 2 FeAl 0.5 Si 0.5 layers was obtained. The simulation explains the experimental result of the resistance versus current hysteresis loop and yields good agreement with the measured critical current. Furthermore, the magnetization trajectory and magnetization distribution were shown and analyzed to elucidate the different characters of two-step switching.

Micromagnetic Simulation of Spin Transfer Torque Magnetization Precession Phase Diagram in a Spin-Valve Nanopillar under External Magnetic Fields

“…The total torque equals to zero at the range of 166 • ≤ θ ≤ 179 • , and the magnetization trajectory precesses with the effective field in this range from the limiting cycle to a band of cycles as shown in Figure 10(b). The quasiperiodic magnetization trajectory filling a bent torus was also shown in [46,47], but we give the explanation of this mode formation. The explanation of the "beat" phenomenon is that since the range of θ corresponding to the balance between STT and the Gilbert damping torque increases from 178…”

“…Simulation performed with shorter time step gave the same results. The free layer is discrete in computational cells of 2 × 2 × 2 nm 3 [46]. Figure 2 shows the phase diagram of magnetization precession under perpendicular magnetic fields along z-axis direction.…”

Angular Dependence of Spin Transfer Switching in Spin Valve Nanopillar Based Heusler Alloy

“…The simulation model of spin valve nanopillar is an elliptical geometry with a cross section area of 250 × 190 nm 2 , as shown in Figure 1. It consists of the pinned and free layers separated by a nonmagnetic layer which are CFAS (20 nm)/Ag (4 nm)/CFAS (2.5 nm) [18]. The magnetization of free and pinned layers is initially aligned along -axis which is its easy axis.…”

“…Particularly, the spin valve using Co 2 FeAl 0.5 Si 0.5 (CFAS) Heusler alloy as the ferromagnetic electrode presented a high MR ratio of 6.9% with Ag spacer [17]. Several researches have focused on an enhancement of MR ratio of CFAS Heusler alloy; however, the spin transfer switching in the spin valve nanopillars based on this alloy has been rarely presented [18].…”

A phase-field model of phase transitions and domain structures of NiCoMnIn metamagnetic alloys

“…The conventional micromagnetic equation cannot describe a phase transition process [29,30]. Herein, we developed a computational model by combining the phase-field method with a micromagnetic model, to investigate the magnetic and structural phase transitions in MSMAs.…”