Structural, electronic, and magnetic properties of the hexagonal double perovskite Ba2FeIrO6 : a combined computational and experimental investigation

Abstract

Hexagonal double perovskites with face-sharing octahedra represent an important class of materials in which structural connectivity strongly influences electronic and magnetic properties. In this work, the structural, magnetic, and electronic properties of Ba2FeIrO6 were investigated using a combined experimental and computational approach. X-ray powder diffraction confirms the formation of a 6H-type hexagonal structure (space group Math input error), characterized by face-sharing Math input error octahedral dimers. Investigation of the surface electronic configuration by means of X-ray photoelectron spectroscopy suggest the presence of Fe3＋/Fe2＋ and IrMath input error/IrMath input error mixed valence states, while ac and dc magnetic measurements reveal a low-temperature transition at Math input error K with ferrimagnetic-like behavior, supported by DFT+Math input error calculations that indicate an uncompensated antiferromagnetic ground state. Electrical resistivity measurements suggest semiconducting behavior with an activation energy of 0.24 eV. Contrastingly, electronic structure calculations consistently indicate a metallic ground state. The discrepancy between the experimental and theoretical results is discussed in terms of possible grain boundary effects in the polycrystalline sample, and/or limitations in the computational model. The metallic behavior is further rationalized by the 6H hexagonal topology, where face-sharing geometry enhances direct Math input error–Math input error orbital overlap and promotes electronic delocalization. These results demonstrate the strong influence of structural connectivity on the physical properties of Ba2FeIrO6, highlighting the role of Math input error–Math input error interactions in hexagonal double perovskites and providing insight for the design of related functional oxide materials.