Dielectric response and thermally stimulated depolarization current analysis of BaNd1.76Bi0.24Ti5O14 high-temperature microwave capacitors
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Thermally stimulated depolarization current (TSDC) measurements were carried out on BaNd1.76Bi0.24Ti5O14 microwave dielectric ceramics to investigate the relationship between depolarization effects and microwave loss. At microwave frequency, BaNd1.76Bi0.24Ti5O14 ceramics exhibit a high dielectric permittivity of 88, a Qf value of 8800 GHz, and a τ f value of +6.9 ppm/°C. The temperature dependence of dielectric properties indicates the loss value of 0.0015 at 1 MHz above 350 °C. Utilizing TSDC technique, the origins of different relaxations in BaNd1.76Bi0.24Ti5O14 ceramics were identified. Two TSDC relaxation peaks (peak A and peak B) are associated with trap charges and oxygen vacancies, respectively. Activation energies of the relaxation in the polarized specimens were also estimated from TSDC measurement results. Such defects significantly contribute to extrinsic loss.
KeywordsOxygen Vacancy Microwave Dielectric Property Relaxation Peak Trap Charge Thermally Stimulate Depolarization Current
This work is supported by the Natural Science Foundation of China (Grant Nos. 51302142, 51221291 and 51272125), the Landing Plan of Jiangxi Province (Grant No. KJLD14075), China Postdoctoral Science Foundation (Grant Nos. 2013M530620 and 2014T70078), and the Science Foundation of Jingdezhen (Grant No. 2013-1-4).
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