Fe 상태 제어에 의한 BaFe2(PO4)2의 자기적 특성 변화에 관한 연구

Abstract

Inorganic compounds composed of low-dimensional ferromagnets exhibit fascinating properties and provide a rich opportunity to investigate the ferromagnetic ground states, magnetic transitions and magnetization phases. Over the last few decades, 2-dimensional honeycomb lattices have attracted attention in relation to physical phenomena such as superconductivity, magnetism, topological phase and 2-dimensional material graphene. Among these physical phenomena, recent discovery of topological insulators in honeycomb lattices has increased research on honeycomb lattices. We have decided to study BaFe2(PO4)2 (BFPO), which is the 2-dimensional Ising ferromagnet with the first honeycomb lattice. Since there was no report on the change of physical properties according to the sintering condition of BFPO, this study focused on the change of physical properties according to sintering conditions of BFPO. Although the structural change of BFPO due to sintering did not occur through XRD analysis, it was confirmed that the state of Fe due to redox reaction changed into Fe2+ and Fe3+, and the XRD pattern was changed due to the change of the length of binding ion radius. XPS analysis showed that sintering in air increased the ratio of Fe3+ and that of Ar+H2 increased the ratio of Fe2+. Optical band gap measurements show that sintering in the air affects the optical band gap decreases and sintering in the reducing atmosphere affect the optical band gap increases. It is also noteworthy that the changes in magnetic properties are shown in three magnetic state depending on the sintering conditions, and the boundary temperatures of the respective states are different from each other.