Characterization of transport and magnetic properties in thin film La(0.67)(Ca(x)Sr(1-x))(0.33)MnO(3) mixtures

TL;DR

This study investigates how varying calcium and strontium ratios in La(0.67)(Ca(x)Sr(1-x))(0.33)MnO(3) thin films affects their transport and magnetic properties, revealing correlations between composition, disorder, and magnetoresistance.

Contribution

It provides new insights into the relationship between compositional tuning and the resulting transport and magnetic behaviors in manganite thin films.

Findings

Decreased calcium increases lattice mismatch and disorder.

Peak magnetoresistance temperature varies with Sr/Ca ratio.

Room temperature magnetoresistance shows a maximum at certain compositions.

Abstract

We have grown thin films of (100) oriented La_{0.67}(Ca_{x}Sr_{1-x})_{0.33}MnO_{3} on (100) NdGaO_{3} substrates by off-axis sputtering. We have looked at the changes in the resistivity and magnetoresistance of the samples as the Ca/Sr ratio was varied. We find that as the calcium fraction is decreased, the lattice match to the substrate decreases, and the films become more disordered, as observed in transport measurements and the variation in Curie and peak resistance temperatures. We find a correlation between the temperature independent and T^2 terms to the low temperature resistivity. The room temperature magnetoresistance exhibits a maximum as the peak temperature is increased by the substitution of Sr for Ca, and a change in the field dependence to the resistivity at room temperature is observed.