Microwave Dielectric Properties and Thermally Stimulated Depolarization Currents of MgF2‐Doped Diopside Ceramics
Microwave Dielectric Properties and Thermally Stimulated Depolarization Currents of MgF2‐Doped Diopside Ceramics
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DOI：
10.1111/jace.13155
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发表时间：
2014-11
影响因子：
3.9
通讯作者：
Jie Zhang;Y. Zhou;B. Peng;Zhenkun Xie;Xiaohua Zhang;Zhenxing Yue
中科院分区：
文献类型：
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作者：
Jie Zhang;Y. Zhou;B. Peng;Zhenkun Xie;Xiaohua Zhang;Zhenxing Yue
以高品质因数CaMg0.9Zn0.1Si2O6 （CMZS）陶瓷为原料，采用固相反应法制备了一种新型低燃烧介质材料。研究了MgF2对CMZS烧结性能、相组成、晶体缺陷和微波介电性能的影响。实验证明，MgF2不仅可以将烧结温度降低到~1000℃，而且可以显著改善CMZS的微波介电性能。除透辉石为主相外，在所有mgf2掺杂样品中还鉴定出橄榄石为次相。介质温度谱显示，MgF2在CMZS中引起了与氧空位缺陷相关的显著介电弛豫。因此，考虑热激发退极化电流来获得与外在微波介质损耗机制相关的缺陷。与未掺杂的CMZS相比，掺5wt % mgf2的CMZS虽然氧空位浓度明显增加，但Q×f值仍有所提高。在适当掺杂mgf2的情况下，微波介质损耗基本受相组成的影响。在1000℃下烧结得到掺量为5 wt%的mgf2样品，其优异的特性为er = 7.78, Q×f = 151 800 GHz, τf =−26.40 ppm/°C。
A new low-fired dielectric material derived from CaMg0.9Zn0.1Si2O6 (CMZS) ceramics with high quality factor was synthesized by solid-state reaction method. The effects of MgF2 addition on the sinterability, phase composition, crystal defects, and microwave dielectric properties of CMZS were investigated. MgF2 was proved not only to lower the sintering temperature to ~1000°C but also to remarkably modify the microwave dielectric properties of CMZS. In addition to the main diopside phase, forsterite was identified as the secondary phase in all MgF2-doped samples. Dielectric temperature spectra showed that MgF2 induced significant dielectric relaxations associated with oxygen vacancy defects to CMZS. Thermally stimulated depolarization current was, therefore, considered to obtain the defects associated with extrinsic microwave dielectric loss mechanisms. Compared with undoped CMZS, although the concentration of oxygen vacancies showed a notable increase in the 5 wt% MgF2-doped CMZS, the Q×f values were still improved. Here, with proper MgF2-doping, it demonstrated that the microwave dielectric loss was basically influenced by phase composition. The excellent characteristics of er = 7.78, Q×f = 151 800 GHz, and τf = −26.40 ppm/°C were achieved from the 5 wt% MgF2-doped specimens sintered at 1000°C.