Unusual valences and fast electron exchange in MoFe2O4

Studies on Some Titanium-Substituted Fe2MoO4Spinel Oxides

“…The most controversial point in all these studies has been the valence state of the cations and their distribution between the tetrahedral and octahedral sites of the spinel lattice. Studies by Ramdani et al (8) and Domenichini et al (9) have shown that the cations present in the ferrite are Fe>, Fe>, Mo>, and Mo> and the formal valence assignment can be best represented by the equilibrium reactions (8) Fe> #Fe> #Mo> " " Fe> #Fe> #Mo> " " Fe> #Fe> #Mo>.…”

“…Thermoelectric power measurements of all the polycrystalline samples were carried out in argon atmosphere in the temperature range 300-600 K following the procedure described elsewhere (11). The samples were heated at a rate of 200°C/h to avoid any phase separation during the measurements (8).…”

Magnetic and structural phase transitions in the spinel compoundFe1+xCr2−xMa1, Garlea2, Rondinone3 et al. 2014Phys. Rev. B

“…This is consistent with the previous analysis and reflecting the cubic-tetragonal-orthorhombic sequence of structural phase transitions upon decreasing the Fe amount. 37,[39][40][41][42][43] Because of the limited instrumental resolution, the two peaks of the tetragonal phase (x = 0.8) are observed as one broad peak, and two peaks (one is sharp and the other is broad) are observed in the orthorhombic phase instead of three sharp peaks for x = 0.2, 0.3 and 0.6, Fig. 4.…”

“…effect being alternated in the system. [37][38][39][40] Therefore, the primary effect of Fe-doping in this system is to change the average moment on the B-sites and alter the competition of antiferromagnetic interactions between A-B and B-B. For this reason, studying the magnetic and structural lattice of Fe 1+x Cr 2−x O 4 can help to uncover the origin of the orbital ordering effect on the structural transition.…”

“…Both composition and temperature dependences of cubictetragonal-orthorhombic structure transitions had been reported by X-ray powder diffraction (XPD) and specific heat. 37,[39][40][41][42][43] The magnetic properties had been studied by magnetic and Mössbauer effect measurements.…”