Selective dilution and magnetic properties of La_{0.7}Sr_{0.3}Mn_{1-x}M'_xO_3 (M' = Al, Ti)

TL;DR

This study investigates how substituting Mn with Al or Ti in La_{0.7}Sr_{0.3}MnO_3 affects its magnetic properties, revealing non-linear phase evolution and scaling of transition temperature reduction with ionic concentration.

Contribution

It introduces a selective dilution approach to analyze magnetic property changes in La_{0.7}Sr_{0.3}MnO_3 with Al and Ti substitutions, aligning experimental data with molecular-field theory predictions.

Findings

Ferromagnetic transition temperature decreases with substitution.

Saturation magnetic moment diminishes as Mn is replaced.

Non-linear evolution of non-ferromagnetic phases observed.

Abstract

The magnetic lattice of mixed-valence Mn ions in La$_{0.7}$Sr$_{0.3}$MnO$_3$ is selectively diluted by partial substitution of Mn by Al or Ti. The ferromagnetic transition temperature and the saturation moment decreases with substitution in both series. The volume fraction of the non-ferromagnetic phases evolves non-linearly with the substitution concentration and faster than theoretically expected. By presenting the data in terms of selective dilutions, the reduction of $T_\mathrm{c}$ is found to be scaled by the relative ionic concentrations and is consistent with a prediction derived from molecular-field theory.