Electron doping induced magnetic glassy state in phase separated YBaCo$_2$O$_{5.5-\delta}$

TL;DR

This study reveals that electron doping in YBaCo$_2$O$_{5.5-\delta}$ induces a magnetic glassy state at low temperatures, caused by kinetic arrest of magnetic phase transitions and involving phase separation of Co ions.

Contribution

It demonstrates the emergence of a magnetic glassy state due to electron doping and phase separation in YBaCo$_2$O$_{5.5-\delta}$, highlighting the role of kinetic arrest.

Findings

Magnetic glassy state observed at low temperatures.

Absence of conventional spin glass features in ac magnetization.

Magnetic phase separation involving Co ions.

Abstract

The structural, magnetic and transport properties of the layered RBaCo$_2$O$_{5.5}$ cobaltites are sensitive to the oxygen stoichiometry. In this present study, we report the presence of a low-temperature magnetic glassy state in electron-doped polycrystalline YBaCo$_2$O$_{5.5}$ cobaltite. The ac magnetization studies show the absence of conventional spin glass features, while the various dc magnetization studies demonstrate the presence of non-equilibrium magnetic glassy state at low temperature. The magnetic glassy state of this sample results from the kinetic arrest of the first order ferro (or ferri) to antiferromagnetic transition. The role of electron doping in the occurrence of magnetic glassy phenomena is discussed in terms of magnetic phase separation involving the Co3+/Co2+ clusters of the ferrimagnetic phase in the Co3+/Co3+ antiferromagnetic matrix.