Griffiths phase in solid-solution of ferromagnetic manganite and cobaltite

TL;DR

This study identifies the Griffiths phase in La$_{0.6}$Sr$_{0.4}$Mn$_{1-x}$Co$_x$O$_3$ across various compositions, revealing its occurrence in the metallic state above the Curie temperature due to magnetic bond disorder.

Contribution

It demonstrates the presence of Griffiths phase in a ferromagnetic manganite-cobaltite solid solution and explores its unique occurrence in the metallic state, unlike in doped manganites.

Findings

Griffiths phase exists over a wide composition range.

GP arises from antiferromagnetic bonds disrupting ferromagnetic order.

GP can occur in the metallic state above $T_C$.

Abstract

We report the existence of Griffiths phase (GP) over a wide range of $x$ in La$_{0.6}$Sr$_{0.4}$Mn$_{1-x}$Co$_x$O$_3$, the solid solution of ferromagnetic (FM) La$_{0.6}$Sr$_{0.4}$MnO$_3$ and La$_{0.6}$Sr$_{0.4}$CoO$_3$, from magnetization measurements. In this compound, GP arises due to the quenching of randomly distributed Co-O-Mn antiferromagnetic bonds in the FM background. In contrary to divalent doped manganites, GP in the present system can exist entirely in the metallic state above $T_C$ (for $x$$<$0.10). Based on the present study, a magnetoelectronic phase diagram is drawn.