Dynamics of the lattice and spins in the phase-separated manganite (Eu$_{1-x}$Gd$_{x}$)$_{0.6}$Sr$_{0.4}$MnO$_3$

TL;DR

This study explores how Gd substitution affects the slow magnetic and lattice relaxations in phase-separated manganite, revealing suppression of frozen phases and stabilization of paramagnetic insulating states due to disorder and interaction effects.

Contribution

It provides new insights into the influence of Gd doping on phase separation dynamics and lattice-spin interactions in manganite materials.

Findings

Gd substitution suppresses frozen phase-separated phases at low temperatures.

Gd stabilizes the paramagnetic insulating state at intermediate temperatures.

Relaxations follow a stretched exponential, indicating strong frustration effects.

Abstract

We investigated slow relaxations of the magnetostriction and residual magnetostriction of the phase-separated system (Eu$_{1-x}$Gd$_{x}$)$_{0.6}$Sr$_{0.4}$MnO$_3$, in which the metamagnetic transition from a paramagnetic insulating state to a ferromagnetic metallic state is accompanied by a lattice shrinkage. The relaxations are well fitted by a stretched exponential function, suggesting the strong frustraction between the double exchange interaction and Jahn-Teller effect. We have revealed that the Gd substitution suppresses the frozen phase-separated phase at low temperatures and stabilizes the paramagnetic insulating state in the dynamic phase-separated phase at intermediate temperatures. The former origin would be the randomness effect and the latter would be the suppression of the double exchange interaction.