Modified Kondorsky Domain Reversal in Microstructured Phase-Separated Manganites

TL;DR

This study investigates how microstructuring affects magnetic domain reversal in phase-separated manganite films, revealing a modified Kondorsky model due to local magnetic fields, and suggests magnetotransport as a tool for domain control.

Contribution

It demonstrates that microfabrication alters the domain reversal mechanism in manganite films, introducing a modified Kondorsky model influenced by local magnetic fields.

Findings

Microstructures follow a modified Kondorsky model for domain reversal.

Local magnetic fields from reversed domains significantly affect coercivity.

Magnetotransport measurements can probe domain competition in microstructures.

Abstract

The hole-doped manganite (La$_{1-y}$Pr$_{y}$)$_{0.67}$Ca$_{0.33}$MnO$_3$ (LPCMO) shows electronic phase separation between ferromagnetic metallic (FMM) and anti-ferromagnetic charge-ordered insulating (AFM-COI) regions. In this study, (La$_{0.5}$Pr$_{0.5}$)$_{0.67}$Ca$_{0.33}$MnO$_{3}$ (LP5CMO) microstructures were fabricated using photolithography on thin films grown on (110) NdGaO$_3$ (NGO) substrates. We investigated the domain reversal mechanism of these microstructures through magnetotransport measurements. Our results demonstrate that, while bulk (unpatterned) films follow the standard Kondorsky model for domain reversal, the microstructures obey a modified Kondorsky model. This difference indicates that local magnetic fields from reversed domains significantly influence the coercive field in confined geometries. Although we did not observe a strong electric field effect, this study establishes that magnetotransport measurements are a feasible method for probing the competition between shape and magnetocrystalline anisotropy in manganite microstructures, which could provide an alternative path for controlling magnetic domains at low current densities.