Effect of Ga doping on magnetotransport properties in collosal magnetoresistive La0.7Ca0.3Mn1-xGaxO3 (0 < x < 0.1)

TL;DR

This study investigates how Ga doping affects the magnetic and transport properties of La0.7Ca0.3MnO3, revealing that increased Ga content reduces ferromagnetic interactions and alters electrical and thermal behaviors.

Contribution

It provides new insights into the effects of Ga doping on magnetotransport properties and the underlying magnetic interactions in La0.7Ca0.3MnO3.

Findings

Ga doping reduces Curie temperature

Increased Ga raises polaron binding energy

Magnetoresistivity decreases with Ga content

Abstract

Samples of La0.7Ca0.3Mn1-xGaxO3 with x = 0, 0.025, 0.05 and 0.10 were prepared by standard solid-state reaction. They were first characterized chemically, including the microstructure. The magnetic properties and various transport properties, i.e. the electrical resistivity, magnetoresistivity (for a field below 8T), thermoelectric power and thermal conductivity measured each time on the same sample, are reported. The markedly different behavior of the x = 0.1 sample from those with a smaller Ga content, is discussed. The dilution of the Mn3+/Mn4+ interactions with Ga doping considerably reduces the ferromagnetic double exchange interaction within the manganese lattice leading to a decrease of the Curie temperature. The polaron binding energy varies from 224 to 243 meV with increased Ga doping.