Evidence of nanoscale structural phase separation in large bandwidth La_0.2Sr_0.8MnO₃

Abstract

We have investigated the structural evolution of La_0.2Sr_0.8MnO₃ using temperature dependent high resolution synchrotron x-ray diffraction technique. In a wide temperature range, La_0.2Sr_0.8MnO₃ reveals nanoscale structural inhomogeneity consisting of cubic and tetragonal phases. The present results suggest that domains of nanometer size of the tetragonal (low temperature) phase start nucleating in the cubic (high temperature) phase even above the Néel temperature (TN). The tetragonal phase fraction increases substantially below TN . Detailed analysis suggests that the twinned phase is tetragonal, orbital ordered, and insulating. At temperatures below 170 K, a small amount of the cubic phase is retained. The present results reveal the significance of the connectivity between the nanoscale structural phase separation with the physical properties.