Phase transitions as a function of temperature in BIMGVOX

Phase transitions in BIMGVOX, Bi 2 Mg x V 1-x O 5.5-3x/2-δ , have been studied using a combination of a.c. impedance spectroscopy, differential thermal analysis and variable temperature X-ray powder diffraction. Two composition regions were examined. In the first, below x = 0.10, phase transitions associated with the α, β and γ-phases are observed. In the second region above x = 0.10 the γ'↔ γ transition is clearly observable. Trends in the refined unit cell parameters were particularly indicative of the phase transitions. The results are compared to those obtained for parent compound Bi 4 V 2 O 11-δ .