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LOW-FREQUENCY INTERNAL FRICTION STUDY FOR SrBi2Ta2O9 FERROELECTRIC CERAMICS
Wang Zhi-yong (王志勇), Chen Ting-guo (陈廷国), Zhu Wei-min (朱为民), Fu Jian (傅剑), Yan Hai-xue (宴海学), Li Cheng-en (李承恩)
Acta Physica Sinica (Overseas Edition), 1998, 7 (10):
764-772.
DOI: 10.1088/1004-423X/7/10/008
Low-frequency internal friction (IF) of SrBi2Ta2O9(SBT) ceramics has been measured at temperatures ranging from 293 to 623 K. Two IF peaks, with their locations around 393 K (P1) and 569 K (P2) (f≈1.58 Hz), respectively, are observed. P1 is found to be associated with a relaxation process with activation energy of 0.97 eV and pre-exponential factor of 3.58×10-14 s. Peak shape analyses reveal that P1 can be well described by a broadened Debye peak with the width parameter $\beta$ from 2.70 to 2.92. The mechanism responsible for P1 is proposed to be relaxation of oxygen vacancies near domain walls(DWs). P2 is considered to arise from viscous motion of DWs since it shows characteristics of static hysteresis type. Comparisons for the IF behavior between SBT and Pb(Zr, Ti)O3(PZT) suggest that in SBT oxygen vacancies are much less localized near DWs than that in PZT. This result provides a possible explanation for the weak DW pinning due to oxygen vacancies in SBT.
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