PMZNT弛豫铁电陶瓷在不同外电场下的介电特性

DIELECTRIC RESPONSE OF PMZNT RELAXOR FERROELECTRIC CERAMICS UNDER VARIOUS EXTERNAL FIELDS

对ＰＭＮ－ＰＺＮ－ＰＴ弛豫铁电陶瓷在不同外电场下的介电特性进行了研究．结果表明：直流偏压场与交流测试场对弛豫铁电体的作用相反，增大偏压场导致介电常数的降低，而增大测试场则使介电常数升高．同时频率色散度也呈现了不同的变化趋势．利用超顺电理论及多畴态模型对上述结果进行了定性分析．

The dielectric response of PMN-PZN-PT relaxor ferroelectric ceramics was measured under various external fields. The investigation demonstrates that the influences of increasing DC bias and AC drive are to the contrary:increasing bias results in a decrease of the dielectric constant and a reduction in the degree of frequency dispersion, whereas increase of drive results in an increase of the constant. A qualitative interpretation is given based on the superparaelectric theory and multi_domain state model.