# Quantitative analysis of the influence of keV He ion bombardment on exchange bias layer systems

## TL;DR

This study investigates how keV He ion bombardment affects exchange bias layer systems, revealing that it predominantly weakens smaller grains in the antiferromagnet and significantly reduces rotational magnetic anisotropy, aiding magnetic patterning.

## Contribution

It provides experimental evidence that ion bombardment mainly impacts smaller grains and challenges previous assumptions of uniform anisotropy weakening in exchange bias systems.

## Key findings

- Massive reduction of rotational magnetic anisotropy observed.
- Ion bombardment mainly affects smaller grains in the antiferromagnet.
- Disproves the assumption of uniform weakening of all magnetic anisotropies.

## Abstract

The mechanism of ion bombardment induced magnetic patterning of exchange bias layer systems for creating engineered magnetic stray field landscapes is still unclear. We compare results from vectorial magneto-optic Kerr effect measurements to a recently proposed model with time dependent rotatable magnetic anisotropy. Results show massive reduction of rotational magnetic anisotropy compared to all other magnetic anisotropies. We disprove the assumption of comparable weakening of all magnetic anisotropies and show that ion bombardment mainly influences smaller grains in the antiferromagnet.