Microwave photovoltage and photoresistance effects in ferromagnetic microstrips

TL;DR

This paper explores how ferromagnetic resonance in Permalloy microstrips induces measurable dc voltages and resistance changes, advancing understanding of microwave-induced effects for potential rf magnetic field sensing applications.

Contribution

It provides a phenomenological model explaining microwave photovoltage and photoresistance effects in ferromagnetic microstrips, validated by experimental data.

Findings

Excellent agreement between theory and experiment

Identification of distinct photoresistance and photovoltage characteristics

Potential application in rf magnetic field sensing

Abstract

We investigate the dc electric response induced by ferromagnetic resonance in ferromagnetic Permalloy (Ni80Fe20) microstrips. The resulting magnetization precession alters the angle of the magnetization with respect to both dc and rf current. Consequently the time averaged anisotropic magnetoresistance (AMR) changes (photoresistance). At the same time the time-dependent AMR oscillation rectifies a part of the rf current and induces a dc voltage (photovoltage). A phenomenological approach to magnetoresistance is used to describe the distinct characteristics of the photoresistance and photovoltage with a consistent formalism, which is found in excellent agreement with experiments performed on in-plane magnetized ferromagnetic microstrips. Application of the microwave photovoltage effect for rf magnetic field sensing is discussed.