Study of Structural and Magnetic Properties of Manganese Vanadium Oxide Spinel Materials Mn₃V₃O₈.

Jia-Yen Chen^1*, Wu-Gee Wei¹, Chin-Wei Wang², Yu-Ting Lee³, Chun-Chuen Yang¹

¹Department of Physics, National Central University, Zhongli, Taoyuan 320317, Taiwan, Zhongli, Taoyuan 320317, Taiwan, Taiwan
²Neutron Group, National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu 300092, Taiwan, Taiwan
³Department of Physics, Chung Yuan Christian University, Zhongli, Taoyuan 320314, Taiwan, Taiwan

* Presenter:Jia-Yen Chen, email:jiaddsaltyen@gmail.com

　　This study aims to explore the relationship between the magnetic structure and charge transfer in Mn₃V₃O₈. Variable-temperature neutron diffraction confirms that the crystal structure remains tetragonal with space group I4₁/amd throughout the 3.6–300 K range, in agreement with room-temperature high-resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED) results. Energy-dispersive X-ray spectroscopy (EDS) reveals that the atomic ratio of Mn to V within the crystal adheres to the expected stoichiometry. Extended X-ray absorption fine structure (EXAFS) analysis and bond valence sum (BVS) calculations suggest that Mn and V ions occupy the A and B sites in ratios of 9:1 and 3:7, respectively, thereby optimizing both oxidation states and bond lengths.
　　Magnetic neutron diffraction indicates that the magnetic structure between 3.6 K and 76 K also retains tetragonal symmetry, with the magnetic space group I4₁/am'd'. Magnetic ordering is observed below 76 K, and the temperature dependence of the ordered magnetic moment follows Bloch’s T³⁄² law, consistent with spin-wave theory.

Keywords: Spinel, magnetic ordering, Tetragonal I4₁/amd