Magnetic characteristics of epitaxial NiO films studied by Raman spectroscopy

TL;DR

This study uses Raman spectroscopy to analyze the magnetic properties of epitaxial NiO thin films, revealing how growth conditions and structural factors influence antiferromagnetic behavior and Néel temperature.

Contribution

It introduces a reliable Raman-based method to determine the Néel temperature and links magnetic properties to strain and defects in epitaxial NiO films.

Findings

Néel temperature depends on lattice strain and defects.

Antiferromagnetic coupling varies with growth conditions.

Raman spectroscopy effectively probes magnetic characteristics.

Abstract

Raman spectroscopy is utilized to study the magnetic characteristics of heteroepitaxial NiO thin films grown by plasma-assisted molecular beam epitaxy on MgO(100) substrates. For the determination of the N\'eel temperature, we demonstrate a reliable approach by analyzing the temperature dependence of the Raman peak originating from second-order scattering by magnons. The antiferromagnetic coupling strength is found to be strongly influenced by the growth conditions. The low-temperature magnon frequency and the N\'eel temperature are demonstrated to depend on the biaxial lattice strain and the degree of structural disorder which is dominated by point defects.