• Olsson, Emilia
• Aparicio-Anglès, Xavier
• Leeuw, Nora H. De

Abstract

<p>SmCoO₃ is a perovskite material that has gained attention as a potential substitute for La_1-xSr_xMnO_3-d as a solid oxide fuel cell cathode. However, a number of properties have remained unknown due to the complexity of the material. For example, we know from experimental evidence that this perovskite exists in two different crystal structures, cubic and orthorhombic, and that the cobalt ion changes its spin state at high temperatures, leading to a semiconductor-to-metal transition. However, little is known about the precise magnetic structure that causes the metallic behavior or the spin state of the Co centers at high temperature. Here, we therefore present a systematic DFT+U study of the magnetic properties of SmCoO₃ in order to determine what magnetic ordering is the one exhibited by the metallic phase at different temperatures. Similarly, mechanical properties are difficult to measure experimentally, which is why there is a lack of data for the two different phases of SmCoO₃. Taking advantage of our DFT calculations, we have determined the mechanical properties from our calculated elastic constants, finding that both polymorphs exhibit similar ductility and brittleness, but that the cubic structure is harder than the orthorhombic phase.</p>

Topics

• perovskite
• impedance spectroscopy
• phase
• semiconductor
• density functional theory
• cobalt
• ductility