Disentangle magnon magnetoresistance from anisotropic and spin Hall magnetoresistance in NiFe/Pt bilayers

TL;DR

This study systematically separates magnon magnetoresistance from anisotropic and spin Hall magnetoresistance in NiFe/Pt bilayers, revealing their distinct dependencies and a sign reversal phenomenon, advancing understanding of charge-spin interactions.

Contribution

The paper introduces a method to disentangle different magnetoresistances based on their temperature and field dependence, providing a clearer understanding of charge-spin conversion in magnetic heterostructures.

Findings

Disentangled magnon magnetoresistance from other types.

Identified different temperature and field dependencies.

Observed sign reversal of sine 3 phi component at specific magnetic fields.

Abstract

We conducted a systematic angular dependence study of nonlinear magnetoresistance in NiFe/Pt bilayers at variable temperature and field using the Wheatstone bridge method. We successfully disentangled magnon magnetoresistance from other types of magnetoresistances based on their different temperature and field dependences. Both the spin Hall/anisotropic and magnon magnetoresistances contain sine phi and sine 3 phi components with phi the angle between current and magnetization, but they exhibit different field and temperature dependence. The competition between different types of magnetoresistances leads to a sign reversal of sine 3 phi component at a specific magnetic field, which was not reported previously. The phenomenological model developed is able to account for the experimental results for both NiFe/Pt and NiFe/Ta samples with different layer thicknesses. Our results demonstrate the importance of disentangling different types of magnetoresistances when characterizing the charge-spin interconversion process in magnetic heterostructures.