Spin-orbit interaction enhancement in permalloy thin films by Pt doping

Abstract

The spin-orbit interaction is an inherent part of magnetism, which links up the independent world of spins to the atomic lattice, thus controlling many functional properties of magnetic materials. In the widely used 3d transition metal ferromagnetic films, the spin-orbit interaction is relatively weak, due to low atomic number. Here we show that it is possible to enhance and tune the spin-orbit interaction by adding 5d platinum dopants into permalloy (Ni 81 Fe 19 ) thin films by a cosputtering technique. This is achieved without significant changes of the magnetic properties, due to the vicinity of Pt to meeting the Stoner criterion for the ferromagnetic state. The spin-orbit interaction is investigated by means of transport measurements (the anisotropic magnetoresistance and anomalous Hall effect), ferromagnetic resonance measurements to determine the Gilbert damping, as well as by measuring the x-ray magnetic circular dichroism at the L 3 and L 2 x-ray absorption edges to reveal the ratio of orbital to spin magnetic moments. It is shown that the effective spin-orbit interaction increases with Pt concentration within the 0%-10% Pt concentration range in a way that is consistent with theoretical expectations for all four measurements.

Spin‐Driven Emergent Antiferromagnetism and Metal–Insulator Transition in Nanoscale p‐Si

“…But, the SOC in FET structures is weak due to insignificant intrinsic SOC in Si. Whereas in this study, Ni 81 Fe 19 have relatively large intrinsic SOC, which may give rise to the strong Rashba SOC due to proximity effect . In addition, recent observation of the strong Rashba spin split states at Bi/Si(111) interface also corroborates our hypothesis of Rashba SOC in the Pd/Ni 81 Fe 19 /MgO/p‐Si multilayer specimen.…”

Effect of annealing on the structure and magnetic properties of Co2FeAl0.5Si0.5 thin films on Ge(111)

“…The Gilbert damping parameter, α, decreases for both the 350 °C and 450 °C annealed samples, α = 3.8×10 -3 and 2.9×10 -3 respectively, compared to the as-grown sample, α = 5.6×10 -3 , whilst the extrinsic damping remains approximately constant. The sample annealed at 450 °C shows a Gilbert damping parameter 2-3 times smaller than that of Permalloy [27,28] and compares well to values found in the literature for CFAS and other full Heusler films [29,30]. Above 500 °C, the line width vs frequency data shows a characteristic two-magnon scattering line-shape indicating magnetic inhomogeneities likely due to the presence of mixed magnetic phases within the sample.…”

In-plane direct current probing for spin orbit torque-driven effective fields in perpendicularly magnetized heavy metal/ferromagnet/oxide frames

“…Thus, thermal annealing of Samples A and B lets thermally-activated B ions diffuse toward the HM layer or thermally-activated Ta or W ions migrate toward the FM layer, causing atomic intermixing of the layers 22 . According to recent work 23 , a heavy metal dopant on the ferromagnet resulted in an enhancement in SOI. In this regard, annealing results in suitable atomic mixing with Co, Fe, B, HM, or oxygen atoms in an FM or HM layer, reflecting the presence of an enhanced SOI-driven SHA in Sample B.…”