ausblenden:
Schlagwörter:
ferroelectrics;
high pressure;
phase transition;
X-ray diffraction
Zusammenfassung:
The crystal structure of complex oxide ferroe-lectrics Ba4Sm2Fe2Nb8O30 and Ba4Gd2Fe2Nb8O30 have been studied by means of energy-dispersive X-ray dif-fraction method at high pressure up to 4 GPa at room temperature. At ambient pressure, the crystal structure of both compounds is described by the tetragonal sym-metry with space group P4/mbm. At pressure P~1.8 GPa in Ba4Sm2Fe2Nb8O30 and at P~2.2 GPa in Ba4Gd2Fe2Nb8O30 the structure phase transition have been observed. The orthorhombic structure model with Pba2 space group for high-pressure phase of those com-pounds have been proposed. The baric dependences of lattice parameters and unit cell volumes of Ba4Sm2Fe2Nb8O30 and Ba4Gd2Fe2Nb8O30 compounds have been obtained.
