کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1473811 | 991061 | 2014 | 13 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: The effect of cation ordering and domain boundaries on low loss Ba(BI1/3BII2/3)O3 perovskite dielectrics revealed by high-angle annular dark-field scanning transmission electron microscopy (HAADF STEM) The effect of cation ordering and domain boundaries on low loss Ba(BI1/3BII2/3)O3 perovskite dielectrics revealed by high-angle annular dark-field scanning transmission electron microscopy (HAADF STEM)](/preview/png/1473811.png)
High quality ceramics of Ba((Co0.7Zn0.3)1/3Nb2/3)O3 (BCZN), Ba(Mg1/3Nb2/3)O3 (BMN) and Ba(Mg1/3Ta2/3)O3 (BMT) were prepared by the mixed oxide route using sintering temperatures up to 1620 °C. Products with a high degree of cation ordering exhibited dielectric Q × f values from 83,000 GHz (BCZN) to 360,000 GHz (BMT). High Resolution TEM and aberration-corrected scanning transmission electron microscopy (STEM) revealed ordering domains and type I, II and III boundary structures. High-Angle Angular Dark Field (HAADF) STEM images provided direct evidence of 1:2 ordering and stacking sequences, and the presence of disordered regions within domain boundaries. The exceptionally high Q × f values for BMT are associated with a high degree of B-site ordering and the removal of domain boundaries in large, single domain grains. The catastrophic degradation of Q × f values in BMN after prolonged sintering is associated with formation of a lossy ferroelectric secondary phase (Ba3Nb2O8), and changes to composition and stoichiometry of BMN grains.
Journal: Journal of the European Ceramic Society - Volume 34, Issue 10, September 2014, Pages 2285–2297