Evolution of structural phase coexistence in a half doped manganite Pr_0.5Sr_0.5MnO₃: An evidence for magneto-structural coupling

Abstract

Temperature dependent x-ray diffraction measurements have been performed to understand the implications of magnetic phase coexistence on crystallographic structure in a half-doped manganite Pr_0.5Sr_0.5MnO₃. The compound shows a structural phase transition from high-temperature tetragonal-I4/mcm to low-temperature orthorhombic-Fmmm symmetry around the ferromagnetic to antiferromagnetic transition. Rietveld analysis shows the coexistence of these two structures emerges at high temperature within the ferromagnetic state, and persists down to lowest temperature. Below around 40 K, however, this structural evolution stops, and a significant fraction of untransformed high-temperature phase remains. This agrees with earlier magnetization study, thus establishing its magneto-structural coupling.