Structural and Magnetic Properties in Spinel Oxide Fe_1−xMn_xV₂O₄

Abstract

Structural properties in spinel oxide Fe 1−x Mn x V 2 O 4 for x ≤ 0.4 have been studied using synchrotron powder diffraction experiments. The successive structural phase transitions similar to those observed in FeV 2 O 4 are observed for x = 0.1. Whereas, the only lattice distortion of cubic-to-tetragonal (c > a) is observed for x = 0.3 and 0.4. Furthermore, we have also measured the magnetization and heat capacity. The results indicate that the temperatures of magnetic phase transitions at ferrimagnetic and non-collinear ferrimagnetic order for x ≤ 0.2 correspond to those of structural transitions of orthorhombic and tetragonal (c > a), respectively. On the other hand, the temperatures of ferrimagnetic phase transition for x = 0.3 and 0.4 are consistent with those of structural transition of a cubic-totetragonal phase (c > a). These results are discussed in terms of orbital state of Fe 2+ and V 3+ ions considering the Jahn-Teller effects and spin-orbit coupling.

Orthorhombic distortion and orbital order in the vanadium spinelFeV2O4

“…The ratio decreases as x increases and is significantly different from unity when x 0.2, whereas the FWHM for the 440 c reflection is almost equal to that for the 044 c reflection when x > 0.2. Note that the orthorhombic and compressed tetragonal phases are absent when x 0.3 in these materials [29][30][31][32]. From these results, the crystal system is logically regarded as the P-tetra rather than the elongated tetragonal (c > a) lattice until x = 0.2.…”