Occurrence of Mixed Phase in $\text {Bi}_{0.5}\text {Sr}_{0.5}\text {Mn}_{0.9}\text {Cr}_{0.1}\text {O}_3$ Bulk Sample: Electron Paramagnetic Resonance and Magnetization Studies

Abstract

We study the effects of 10% Cr substitution in Mn sites of Bi$_{0.5}$Sr$_{0.5}$MnO$_3$ on the antiferromagnetic (AFM) ($T_{\text {N}} \sim$ 110 K) transition using structural, magnetic and electron paramagnetic resonance (EPR) techniques. Field cooled (FC) and zero field cooled (ZFC) magnetization measurements done from 400 K down to 4 K show that the compound is in the paramagnetic (PM) phase till 50 K where it undergoes a transition to a short-range ferromagnetic phase (FM). Electron paramagnetic resonance measurements performed in the temperature range of 300 K to 80 K conform with the magnetization measurements as symmetric signals are observed owing to the paramagnetic phase. Below 80 K, signals become asymmetric. Electron paramagnetic resonance intensity peaks at $\sim$ 110 K, the decreasing intensity below this temperature confirming the presence of antiferromagnetism. We conclude that below 50 K the magnetization and EPR results are consistent with a cluster glass phase of BSMCO, where ferromagnetic clusters coexist with an antiferromagnetic background.