Electrical transport and anomalous structural behavior of at high temperature

The study of XRD patterns of α - Eu 2 ( MoO 4 ) 3 modulated scheelite reveals an anomalous behavior of its lattice parameter a in the range of temperatures from 473 to 973 K. We have analyzed the real part of the complex conductivity in the frequency range from 0.1 to 10,000 kHz and the temperature range from 550 to 900 K, and found that it follows a universal dielectric response. Detailed analysis of the temperature dependence of the adjusted parameters within this model shows that, in a temperature range, the dominant mechanism of electrical transport is due to the overlapping of large polarons. Rietveld refinements were performed using symmetry adapted modes at 523, 723 and 923 K in order to study the thermal dependence of the distortion from the scheelite structure and to interpret the structural effects that favor the formation of polarons.