Fe-doping-induced evolution of charge-orbital ordering in a bicritical-state manganite

TL;DR

This study investigates how Fe doping affects charge-orbital ordering and magnetic properties in a bicritical manganite, revealing that Fe induces phase separation and suppresses ferromagnetism, contrasting with effects of Cr doping.

Contribution

It provides new insights into impurity effects on charge-orbital order and magnetic phase stability in manganites, highlighting Fe's unique role.

Findings

Fe doping significantly lowers the ferromagnetic transition temperature.

Charge-orbital ordering develops at low temperatures with Fe doping.

Fe doping induces phase-separated states with short-range order.

Abstract

Impurity effects on the stability of a ferromagnetic metallic state in a bicritical-state manganite, (La0.7Pr0.3)0.65Ca0.35MnO3, on the verge of metal-insulator transition have been investigated by substituting a variety of transition-metal atoms for Mn ones. Among them, Fe doping exhibits the exceptional ability to dramatically decrease the ferromagnetic transition temperature. Systematic studies on the magnetotransport properties and x-ray diffraction for the Fe-doped crystals have revealed that charge-orbital ordering evolves down to low temperatures, which strongly suppresses the ferromagnetic metallic state. The observed glassy magnetic and transport properties as well as diffuse phase transition can be attributed to the phase-separated state where short-range charge-orbital-ordered clusters are embedded in the ferromagnetic metallic matrix. Such a behavior in the Fe-doped manganites form a marked contrast to the Cr-doping effects on charge-orbital-ordered manganites known as impurity-induced collapse of charge-orbital ordering.