Disorder effects at low temperatures in La_{0.7-x}Y_{x}Ca_{0.3}MnO_{3} manganites

TL;DR

This study investigates how magnetic disorder affects low-temperature excitations in La_{0.7-x}Y_{x}Ca_{0.3}MnO_{3} manganites, revealing enhanced specific heat linked to disorder and corroborated by resistivity data.

Contribution

It demonstrates the impact of yttrium doping on magnetic disorder and low-temperature specific heat behavior in manganites, introducing new insights into disorder effects.

Findings

Yttrium doping induces a cluster-glass state.

Enhanced linear specific heat term due to magnetic disorder.

Resistivity measurements support specific heat findings.

Abstract

With the aim of probing the effect of magnetic disorder in the low-temperature excitations of manganites, specific-heat measurements were performed in zero field, and in magnetic fields up to 9 T in polycrystalline samples of La_{0.7-x}Y_{x}Ca_{0.3}MnO_{3}, with Y concentrations x=0, 0.10, and 0.15. Yttrium doping yielded the appearance of a cluster-glass state, giving rise to unusual low-temperature behavior of the specific-heat. The main feature observed in the results is a strong enhancement of the specific-heat linear term, which is interpreted as a direct consequence of magnetic disorder. The analysis was further corroborated by resistivity measurements in the same compounds.