Ferromagnetic resonance and interlayer exchange coupling in magnetic multilayers with compositional gradients

TL;DR

This study investigates ferromagnetic resonance in layered magnetic structures with compositional gradients, revealing how weak interlayer exchange interactions can be detected and characterized, especially near Curie temperatures, aiding in the design of thermally-controlled magnetic nanostructures.

Contribution

It introduces a method to detect weak signals from spacer layers with compositional gradients in magnetic multilayers, enabling detailed study of interlayer exchange interactions.

Findings

Detection of weak spacer signals in FMR measurements.

Temperature-dependent exchange interaction properties near Curie points.

Insights for designing thermally-controlled magnetic nanostructures.

Abstract

Ferromagnetic resonance (FMR) in magnetic multilayers of type F1/f/F2, where two strongly ferromagnetic layers F1 and F2 are separated by a weakly magnetic spacer f with a compositional gradient along its thickness, is investigated. The method allows to detect the weak signal from the spacer in additional to the more pronounced and readily measured signal from the outer strongly-magnetic layers, and thereby study the properties of the spacer as well as the interlayer exchange interaction it mediates. Variable temperature FMR measurements, especially near the relevant Curie points, reveal a rich set of properties of the exchange interactions in the system. The obtained results are useful for designing and optimizing nanostructures with thermally-controlled magnetic properties.