Enhancing the limit of uniaxial magnetic anisotropy induced by ion beam erosion

TL;DR

This study demonstrates a method to significantly enhance in-plane uniaxial magnetic anisotropy in cobalt films by combining sequential deposition with ion beam erosion, resulting in stronger anisotropy than previously reported.

Contribution

It introduces a novel approach of sequential deposition and ion beam erosion to engineer and amplify magnetic anisotropy in thin films.

Findings

UMA is about ten times larger than previous reports.

Surface ripples and biaxial texture contribute to enhanced anisotropy.

Method is applicable to various magnetic systems.

Abstract

The artificial tailoring of magnetic anisotropy by manipulation of interfacial morphology and film structure are of fundamental interest from application point of view in spintronic and magnetic memory devices. This letter reports an approach of engineering and enhancing the strength of oblique incidence ion beam erosion (IBE) induced in-plane uniaxial magnetic anisotropy (UMA) by simultaneous modification of film morphology as well as film texture. To meet this objective, Cobalt film and Si substrate have been taken as a model system. Unlike conventional post growth IBE of film, we direct our effort to the sequential deposition and subsequent IBE of the film. Detailed in-situ investigation insights that the film grows in highly biaxially textured polycrystalline state with formation of nanometric surface ripples. The film also exhibits pronounced UMA with easy axis oriented parallel to the surface ripple direction. Remarkably, the induced UMA is about one order of magnitude larger than the reported similar kind of earlier studies. The possibility of imposing in-plane crystallographic texture giving rise to magneto-crystalline anisotropy, along with long-range dipolar interaction throughout ripple crests enhances the strength of the UMA. The present findings can be further extended to systems characterized by different crystallographic structure and magnetic properties and show the general applicability of the present method.