Al-Substitution Effects on Physical Properties of the Colossal Magnetoresistance Compouns La0.67ca0.33mno3

TL;DR

This study investigates how aluminum substitution affects the structural, magnetic, and electrical properties of La0.67Ca0.33MnO3 manganites, revealing changes in magnetoresistance and Curie temperature due to disorder.

Contribution

It provides a detailed experimental analysis of Al doping effects on manganites' properties, highlighting the role of disorder and magnetic clustering.

Findings

All samples exhibit colossal magnetoresistance.

Curie temperatures decrease with increasing Al content.

Magnetic clusters are present near the ferromagnetic transition.

Abstract

We present a detailed study of the polycrystalline perovskite manganites La0.67Ca0.33AlxMn1-xO3 (x = 0, 0.1, 0.15, 0.5) at low temperatures and high magnetic fields, including electrical resistance, magnetization, ac susceptibility. The static magnetic susceptibility was also measured up to 1000 K. All the samples show colossal magnetoresistance behavior and the Curie temperatures decrease with Al doping. The data suggest the presence of correlated magnetic clusters near by the ferromagnetic transition. This appears to be a consequence of the structural and magnetic disorder created by the random distribution of Al atoms.