The enhancement of phase separation aspect in electron doped manganite Ca0.8Sm0.16Nd0.04MnO3

TL;DR

This study investigates phase separation effects in Ca0.8Sm0.16Nd0.04MnO3, revealing a first-order structural transition, hysteretic metamagnetic behavior, and a metal-insulator transition linked to electron clustering and magnetic ordering.

Contribution

It demonstrates enhanced phase separation phenomena in electron-doped manganites due to lanthanide doping, highlighting structural and magnetic transitions in Ca0.8Sm0.16Nd0.04MnO3.

Findings

First-order structural transition at ~158 K with latent heat

Hysteretic metamagnetic behavior below transition temperature

Metal-insulator transition at ~112 K associated with electron clustering

Abstract

The complex lanthanide doping of electron manganites results in enhancement of various phase separation effects in physical properties of these compounds. Selecting Ca0.8Sm0.16Nd0.04MnO3 as a model case we show that the first order structural phase transition from paramagnetic semi-metallic phase into anti-ferromagnetic semi-metallic phase at TS ~ 158 +- 4 K is marked by an abrupt decrease in magnetization, a step like anomaly DL/L = 10-4 in thermal expansion and large latent heat DQ = 610 J/mol. In a certain temperature range below TS, the high field magnetization exhibits hysteretic metamagnetic behavior due to field-induced first order transformation. ac-susceptibility, magnetization and resistivity data suggest rather a non-uniform state in Ca0.8Sm0.16Nd0.04MnO3 at low temperatures. The metal - insulator transition occurs at TMI ~112 +- 3 K, accompanied by a step-like increase in magnetization. These features could be ascribed to "sponging" of electrons from neighboring anti-ferromagnetic matrix by clusters undergoing the ferromagnetic ordering.