A universal platform for magnetostriction measurements in thin films

TL;DR

This paper introduces a universal nanomechanical platform using a silicon nitride nanobeam resonator to accurately measure magnetostriction in thin films, applicable to various materials and deposition methods.

Contribution

The authors develop a novel, versatile measurement technique for quantifying magnetostriction in thin films using nanomechanical resonators, demonstrating its effectiveness with cobalt films.

Findings

Accurately measured magnetostriction constants of cobalt thin films.

Method shows good agreement with literature values.

Applicable to various conducting and insulating thin films.

Abstract

We present a universal nanomechanical sensing platform for the investigation of magnetostriction in thin films. It is based on a doubly-clamped silicon nitride nanobeam resonator covered with a thin magnetostrictive film. Changing the magnetization direction within the film plane by an applied magnetic field generates a magnetostrictive stress and thus changes the resonance frequency of the nanobeam. A measurement of the resulting resonance frequency shift, e.g. by optical interferometry, allows to quantitatively determine the magnetostriction constants of the thin film. We use this method to determine the magnetostriction constants of a 10nm thick polycrystalline cobalt film, showing very good agreement with literature values. The presented technique can be useful in particular for the precise measurement of magnetostriction in a variety of (conducting and insulating) thin films, which can be deposited by e.g. electron beam deposition, thermal evaporation or sputtering.