Anomalous High Temperature Structural Behavior of Potential Multifunctional Material SmCo_0.5Cr_0.5O₃

Abstract

Crystal structure parameters of the mixed cobaltite–chromite SmCo0.5Cr0.5O3 in the temperature range of 298–1173 K were derived from in situ high‐resolution X‐ray synchrotron powder diffraction data. Similar to the parent SmCoO3 compound, SmCo0.5Cr0.5O3 reveals anomalous thermal expansion reflected in abnormal temperature dependence of the unit cell dimensions and the selected interatomic distances and angles. These anomalies are associated with temperature induced changes of spin state of Co3+ ions and coupled insulator‐metal transition. Observed decreasing behavior of the bandwidth W points on the increasing population of the exited spin states of Co3+ ions in SmCo0.5Cr0.5O3 with increasing temperature. First principle calculations revealed antiferromagnetic ground state of SmCo0.5Cr0.5O3 as the most stable.