Nonresonant microwave absorption in epitaxial La-Sr-Mn-O films and its relation to colossal magnetoresistance

TL;DR

This paper investigates nonresonant microwave absorption in La-Sr-Mn-O films, linking it to colossal magnetoresistance, and presents a model for magnetic-field-dependent magnetoresistance useful for contactless magnetic property measurements.

Contribution

It introduces a model for magnetoresistance in thin ferromagnetic films under oblique magnetic fields, connecting microwave absorption to colossal magnetoresistance phenomena.

Findings

Microwave absorption originates from colossal magnetoresistance.

The developed model fits experimental data well.

Microwave technique enables contactless magnetic property measurement.

Abstract

We study magnetic-field-dependent nonresonant microwave absorption and dispersion in thin La$_{0.7}$Sr$_{0.3}$MnO$_{3}$ films and show that it originates from the colossal magnetoresistance. We develop the model for magnetoresistance of a thin ferromagnetic film in oblique magnetic field. The model accounts fairly well for our experimental findings, as well as for results of other researchers. We demonstrate that nonresonant microwave absorption is a powerful technique that allows contactless measurement of magnetic properties of thin films, including magnetoresistance, anisotropy field and coercive field.