Pressure-Induced Structural Phase Transition from Relaxor Phase to Antiferroelectric Phase in Disordered Pb(In1/2Nb1/2)O3

The pressure dependence in the disordered Pb(In 1/2 Nb 1/2 )O 3 (PIN) single crystals (S=0.4 (type(I)), 0.2 (type(II))) were investigated by X-ray diffraction. The pressure dependence of the cell parameters and the integrated intensities of the ( h /4 k /4 0) superlattice reflections associated with the antiparallel shift of lead cations were measured. The phase transition from the pseudo-cubic structure to the orthorhombic one was observed at about 0.4 GPa in the disordered-type(I) crystal. But no phase transition was observed below 0.8 GPa in the disordered-type(II) crystal. The disordered-type(I) crystal at higher pressure than 0.4 GPa was isostructural with the ordered crystal at the atmospheric pressure. But with increasing pressure in the disordered-type(I) crystal, the integrated intensities of the ( h /2 k /2 l /2) reflections associated with the In/Nb arrangement did not change. The antiferroelectric phase was obtained not only by changing the In/Nb arrangement with isothermal annealing but also by applying pressure above 0.4 GPa in the disordered-type(I) crystal.