摘要
Spontaneous polarization was found in Ta_(2)O_(5)dielectric ceramics prepared by laser sintering techmique.After heat corrosion,90°and 180°domains in the ceramics was observed by field emission scanning electron micrographs.The crystal structure of the laser-si ntered ceramics at RT was determined as monocinic phase,which indicates the lattice distortion existed in the ceramics.The variation of O-Ta-O bending vibration mode was deduced from the variation of phonon mode at the low wave-mumber(57 cm^(-1)and 250cm^(-1)).The enhancement of effective electric field for tantalum atoms due to the lattice distortion was determined by calculation of charge distribution cofficients.The distortion of crystal structure due to the phase transformation from higher symmetric orthorhombic phase to lower symmetric monoclinic phase expl ained spontaneous polarization in the laser-sintered Ta_(2)O_(5)ceramics.
基金
National Nature Science Foundation of China(50875006)
Beijing Natural Science Foundation(2082005)
Scienti¯c Research Common Program of Beijing Municipal Commission of Education(KM200810005006)for their support.
