Control of Ferrimagnetic Compensation and Perpendicular Anisotropy in Tb$_x$Co$_{(100-x)}$ with H$^{+}$ ion implantation

TL;DR

This study demonstrates that hydrogen ion implantation can precisely tune the magnetic compensation point and anisotropy transition in Tb-Co alloys, offering a controlled method to manipulate magnetic properties without other ionic effects.

Contribution

It provides a quantitative analysis of hydrogen's effect on magnetic properties of Tb-Co alloys using ion implantation, isolating hydrogen's role from other electrochemical factors.

Findings

Hydrogen implantation shifts compensation and anisotropy transition compositions by 6 at.% towards higher Tb concentrations.

The shift in magnetic properties is independent of hydrogen dose beyond a certain point.

Reduction of the Tb sublattice moment explains the change in compensation composition.

Abstract

The tuning of magnetic properties through electrochemical loading of hydrogen has recently attracted significant interest as a way to manipulate magnetic devices with electric fields. In this paper we investigate quantitatively the magneto-ionic effect of hydrogen uptake on the magnetic properties of rare-earth transition metal alloy Tb$_x$Co$_{(100-x)}$ in the composition range of $x=10-39$ at.\% using ion implantation. Using this technique we are able to link changes in magnetic behaviour to exact concentrations of hydrogen, isolated from the movement of any other ions that would be a factor in electrochemical studies. The composition of the alloy has been varied alongside the hydrogen dose to characterize the effect of progressive hydrogen loading on the full range of $x$ displaying out-of-plane magnetic anisotropy. We find large changes in two important properties: the compensation composition and the Co-rich in-plane to out-of-plane magnetic anisotropy transition composition, both of which move by 6 at.\% towards higher Tb concentrations after hydrogen implantation. This shift in composition does not increase with a larger dose. From the changes in magnetization we attribute the change in compensation composition to a significant reduction of the moment on the Tb sublattice.