Investigation of the phase separation property in La$_{0.2}$Pr$_{0.4}$Ca$_{0.4}$MnO$_3$ manganite

TL;DR

This study investigates phase separation in La0.2Pr0.4Ca0.4MnO3 manganite, revealing magnetic transitions, phase conversion under magnetic fields, and the absence of spin glass behavior, with implications for understanding mixed-valent manganites.

Contribution

It provides detailed insights into the micrometre scale phase separation and magnetic field-induced phase transitions in La0.2Pr0.4Ca0.4MnO3, highlighting the nature of its low-temperature phases.

Findings

Charge-ordered state converts to ferromagnetic state with magnetic field.

Absence of spin glass behavior at low temperatures.

Sharp resistivity drop indicating phase transition from COI to FMM.

Abstract

We report a comprehensive investigation of La0.2Pr0.4Ca0.4MnO3 to clarify the micrometre scale phase separation phenomenon in the mixed valent manganite (La,Pr,Ca)MnO3. The compound shows multiple magnetic transitions, in which the charge-ordered state is converted into a ferromagnetic state in steps with the application of a magnetic field. The ac susceptibility measurements show that the glassy transition at low temperatures does not depend on the frequency, thus indicating the absence of any spin glass behaviour. Magnetization as well as heat capacity measurements indicate that this low temperature transition is magnetic field dependent. The field dependent resistivity at 2K shows a sharp drop indicating that the sample behaviour changes from a high resistive state to a low resistive state, corroborating the conversion of charge-ordered insulating (COI) phase to a ferromagnetic metallic (FMM) phase. Our results point towards the existence of phase separation, rigidity of the low temperature glassy-like phase as well as the conversion of COI phase to FMM phase by the application of magnetic fields.