Tuning the N\'eel temperature in an antiferromagnet: the case of NixCo1-xO microstructures

TL;DR

This study demonstrates how varying the Ni to Co ratio in Ni-Co oxide microstructures allows tuning of the Neel temperature, with detailed characterization of their structure, composition, and magnetic properties.

Contribution

It introduces a method to control the Neel temperature in Ni-Co oxide films through compositional adjustments during growth.

Findings

Neel temperature can be tuned by changing Ni/Co ratio.

Antiferromagnetic domains up to micrometer size observed.

Microstructures characterized by advanced microscopy and spectroscopy.

Abstract

We show that it is possible to tune the N\'eel temperature of nickel(II)-cobalt(II) oxide films by changing the Ni to Co ratio. We grow single crystalline micrometric triangular islands with tens of nanometers thickness on a Ru(0001) substrate using high temperature oxygen-assisted molecular beam epitaxy. Composition is controlled by adjusting the deposition rates of Co and Ni. The morphology, shape, crystal structure and composition are determined by low-energy electron microscopy and diffraction, and synchrotron-based x-ray absorption spectromicroscopy. The antiferromagnetic order is observed by x-ray magnetic linear dichroism. Antiferromagnetic domains up to micrometer width are observed.