Magnetic dilution on LaCrO$_3$

TL;DR

This study investigates how substituting Al for Cr in LaCrO$_3$ affects its crystal structure and magnetic properties, revealing a phase transition and a significant decrease in Nél temperature due to magnetic dilution.

Contribution

It provides new insights into the structural and magnetic changes induced by Al doping in LaCrO$_3$, including phase transition and magnetic order disruption.

Findings

Structural phase transition caused by Al doping.

Significant decrease in Nél temperature with Al substitution.

Magnetic behavior remains antiferromagnetic with slight spin canting.

Abstract

In this work, we study the effect of the magnetic dilution of Cr$^{3+}$ on the LaCrO$_3$ half doped with Al. Pure and half-doped samples were prepared by combustion method using urea as fuel. The crystal structure was investigated by X-ray diffraction. Rietveld analysis reveal a structural phase transition caused by the increase of the chemical pressure due difference of Al$^{3+}$ and Cr$^{3+}$ ionic radii. SEM images shows that the samples exhibit a spherical formation and irregular morphologies. Magnetization measurements as a function of temperature reveal an antiferromagnetic order in both samples with a large decrease of T$_N$ (N\'eel temperature) with Al doping. The reduction of frustration factor and the increase of the magnetic moment of the doped sample could be attributed to the breaking of the long-range antiferromagnetic order. The magnetic hysteresis loops show a typical antiferromagnetic behavior with a slightly spin canting for the doped sample.