Interface-induced spin Hall magnetoresistance enhancement in Pt-based tri-layer structure

Abstract

In this study, we integrated bilayer structure of covered Pt on nickel zinc ferrite (NZFO) and CoFe/Pt/NZFO tri-layer structure by pulsed laser deposition system for a spin Hall magnetoresistance (SMR) study. In the bilayer structure, the angular-dependent magnetoresistance (MR) results indicate that Pt/NZFO has a well-defined SMR behavior. Moreover, the spin Hall angle and the spin diffusion length, which were 0.0648 and 1.31 nm, respectively, can be fitted by changing the Pt thickness in the longitudinal SMR function. Particularly, the MR ratio of the bilayer structure (Pt/NZFO) has the highest changing ratio (about 0.135%), compared to the prototype structure Pt/Y3Fe5O12 (YIG) because the NZFO has higher magnetization. Meanwhile, the tri-layer samples (CoFe/Pt/NZFO) indicate that the MR behavior is related with CoFe thickness as revealed in angular-dependent MR measurement. Additionally, comparison between the tri-layer structure with Pt/NZFO and CoFe/Pt bilayer systems suggests that the SMR ratio can be enhanced by more than 70%, indicating that additional spin current should be injected into Pt layer.

Interfacial spin structures in Pt/Tb3Fe5O12 bilayer films on Gd3Yadav, Bake, Lee et al. 2023Phys. Rev. Materials1000View full textAdd to dashboardCite

“…The most well-known form of MPE is where a thin interfacial region in the nonmagnetic metal exhibits an induced moment through exchange with the magnetic layer. However, there are closely related effects, such as interface-induced spin anisotropy and dynamic MPE, which can also be considered proximity effects, although these do not necessarily lead to a locally modified magnetization magnitude [16]. MPE-induced magnetism contributes to the HM's magnetoresistance and couples to the ferromagnet's magnetic moment, making the MPE an essential element in defining the behavior of HM/magnetic heterostructures, especially at low temperatures where the MPE is stronger.…”

Impact of Symmetry on Anisotropic Magnetoresistance in Textured Ferromagnetic Thin Films

“…Since the first pioneering experiment one branch of research deals with investigating the SMR in all-metallic multilayers; however, the outcome is not conclusive. As also pointed out by Zou et al [45] the structural properties, particularly the crystallinity of the films, are mandatory for a profound interpretation of MR data; however, they are often disregarded or not considered [34,[40][41][42][55][56][57][58][59] even in carefully performed studies [60,61]. Frequently, Δρ op signatures are ad hoc interpreted to be a fingerprint of the SMR while not thoroughly proven whether crystalline or interfacial AMR effects exist [34,[39][40][41][42][55][56][57][58][59]62].…”

“…Frequently, Δρ op signatures are ad hoc interpreted to be a fingerprint of the SMR while not thoroughly proven whether crystalline or interfacial AMR effects exist [34,[39][40][41][42][55][56][57][58][59]62]. The studies particularly lack an appropriate modeling of the electronic transport in all-metallic layered structures including the consideration of interface-scattering processes [39][40][41][42][55][56][57][58][59][60][61]63]. Properly correcting for the current shunt through paramagnetic layers provides the feasibility for the separation of interface and bulklike MR contributions [30], which is a necessary prerequisite to check for the validity of Eq.…”