Mechanism of the Pyroelectric Response under Direct-Current Bias in La-Modified Lead Zirconate Titanate Stannate Ceramics - Zhang, Hong-Ling (红玲 张); Wang, Gen-Shui (根水 王); Chen, Xue-Feng (学锋 陈); Cao, Fei (菲曹); Dong, Xian-Lin (显林 董); Gu, Yan (岩谷); He, Hong-Liang (红亮 贺); Liu, Yu-Sheng (雨生 刘) (Chinese physics letters, 2011)