Structural effects of the spin-state crossover at high temperature in the distorted ErCoO3 cobaltite

Abstract

We present a neutron powder diffraction study reporting structural evidences of a spin- state crossover beginning at Tss≈575 K in the highly distorted ErCoO3 cobaltite, based on measurements in the temperature range 100 K - 1000 K. Different interrelated changes in the structural evolution upon heating have been described, which are driven by an anomalous expansion of the octahedra. The activation of IS or HS spin states brings about an expansion of the CoO6 octahedra (increase of Co-O bond lengths), and the augmentation of the Co-O distances in the a-b plane respect to that along the c-axis. The spin-state crossover extends over a broad temperature interval and can be monitored by an atypical augmentation of the orthorhombic strain.