Magnetic structure, magnetoelastic coupling, and thermal properties of EuCrO$_3$ nano-powders

TL;DR

This study investigates the magnetic, magnetoelastic, and thermal properties of EuCrO$_3$ nano-powders, revealing a G_x antiferromagnetic structure and a magnetoelastic anomaly around 100 K through comprehensive diffraction and spectroscopic analyses.

Contribution

First detailed neutron and X-ray diffraction analysis of EuCrO$_3$ nano-powders, identifying magnetic structure and magnetoelastic coupling phenomena.

Findings

EuCrO$_3$ exhibits a G_x antiferromagnetic structure with ~2.4 μ_B moments.

An anomaly at ~100 K indicates magnetoelastic distortion.

Multiple measurement techniques confirm the magnetoelastic coupling.

Abstract

We carried out detailed studies of the magnetic structure, magnetoelastic coupling, and thermal properties of EuCrO$_3$ nano-powders from room temperature to liquid helium temperature. Our neutron powder diffraction and X-ray powder diffraction measurements provide precise atomic positions of all atoms in the cell, especially for the light oxygen atoms. The low-temperature neutron powder diffraction data revealed extra Bragg peaks of magnetic origin which can be attributed to a $G_x$ antiferromagnetic structure with an ordered moment of $\sim$ 2.4 $\mu_{\rm B}$ consistent with the $3d^3$ electronic configuration of the Cr$^{3+}$ cations. Apart from previously reported antiferromagnetic and ferromagnetic transitions in EuCrO$_3$ at low temperatures, we also observed an anomaly at about 100 K. This anomaly was observed in temperature dependence of sample's, lattice parameters, thermal expansion, Raman spectroscopy, permittivity and conductance measurements. This anomaly is attributed to the magnetoelastic distortion in the EuCrO$_3$ crystal.