Abstract
The 180° light scattering experiment has been performed with the SrTiO 3 , 0.02 wt% Nb-doped SrTiO 3 , and 0.05 wt% Nb-doped SrTiO 3 samples. The broad doublet is found to become weaker with increasing Nb-concentration. Furthermore, the total scattering intensity is found to show the anomalous behavior below T q = 37 K in the SrTiO 3 and 0.02 wt% Nb-doped SrTiO 3 samples. These results strongly suggest that there exist the ferroelectric regions in these materials with the length-scale of the order of 100 nm below Tq.
Acknowledgments
The authors express their appreciation to Mr. Takao Ohta for his polishing the samples so as to have the optical grade surfaces. The present work has been supported in part by a Grant-in-Aid for Scientific Research (C) from the Ministry of Education, Science, Sports and Culture of Japan, No. 19540325.