Direct observation of current-induced nonlinear spin torque in Pt-Py bilayers

Abstract

We experimentally observe nonlinear spin torque in metallic bilayers of platinum and permalloy by means of spin-torque ferromagnetic-resonance (ST-FMR) under massive dc current injection. The observed nonlinear spin torque exerted to permalloy magnetization is attributed primarily to nonlinear spin polarization. Additional origin of the nonlinear spin torque is magnon generation (annihilation) followed by shrinkage (expansion) of effective magnetization, which is reveled by STFMR and unidirectional spin Hall magnetoresistance measurements. The present study paves a way to spin-Hall effect based nonlinear spintronic devices as well as time-varying nonlinear magnetic metamaterials with tailor-made permeability.

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• Generation of Multipeak Spectrum of Spin Torque Oscillator in Non-linear Regime

Cited by in corpus (2)

• Nonlinear Edelstein Effect in Strongly Correlated Electron Systems
• Light-induced nonlinear Edelstein effect under ferroaxial ordering