Tailoring magnetocrystalline anisotropy of FePt by external strain

Abstract

We propose using strain assisted reduction in anisotropy of FePt to control magnetization reversal in the writing on the magnetic storage devices. Our first-principles calculations show 21% decrease of the magnetocrystalline anisotropy energy (MAE) with application of 1.5% tensile biaxial strain. The reduction of MAE is primarily due to the change of the c/a ratio and to some extent due to the increase in volume. We propose building bilayer (or heterostructure) of FePt and piezoelectric film. This system is expected to allow the control of anisotropy constant by applying electric field to the system. Finally, we discuss the possibility of forming medium using bi-layer of FePt and soft magnetic material with the gradient of anisotropy constant.