High-temperature ferroic phase transitions and paraelectric cubic phase in multiferroic Bi0.95+δFe0.9Zr0.1O3

The temperature-dependent phase transitions of Bi(0.95+delta)dFe(0.9)Zr(0.1)O(3) have been studied using hightemperature x-ray powder diffraction together with differential scanning calorimetry measurements. The results show that Bi(0.95+delta)dFe(0.9)Zr(0.1)O(3) undergoes two phase transitions at 815 degrees C and 905 degrees C before decomposition at 920 degrees C. It appears that Zr-doping seems to stabilize the high temperature phases in such compound. Both the sharp contraction in the unit-cell volume and enthalpy thermal hysteresis demonstrate that the ferroelectric phase transition (alpha <-> beta) at 815 degrees C is of first order nature. In contrast, the highest beta <-> gamma phase transition at 905 degrees C appears to be a second-order-like one. The analysis of the diffraction pattern in addition to Rietveld refinement strongly suggests a cubic symmetry for gamma-phase. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4729484]