کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1460757 989609 2015 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
High-temperature colossal dielectric response in RFeO3 (R=La, Pr and Sm) ceramics
موضوعات مرتبط
مهندسی و علوم پایه مهندسی مواد سرامیک و کامپوزیت
پیش نمایش صفحه اول مقاله
High-temperature colossal dielectric response in RFeO3 (R=La, Pr and Sm) ceramics
چکیده انگلیسی

Polycrystalline RFeO3 (R=La, Pr, and Sm) ceramics have been synthesized by a modified Pechini method. All the refined X-ray diffraction patterns reveal that the materials crystallized in orthorhombic structure with space group Pbnm. Clear grain and grain boundary are evident in PrFeO3 and SmFeO3 ceramics after sintering at 1200 °C for 4 h by scanning electron microscopy. Mixed valence of Fe2+/Fe3+ has been determined using X-ray photoelectron spectroscopy. High-temperature dielectric behavior and impedance spectrum over the frequency range of 100 Hz to 10 MHz are investigated at different temperatures from 300 to 600 K. These materials exhibit relaxation-like dielectric behavior and colossal dielectric constant in a wide temperature and frequency range. Impedance spectrum analysis indicates the ceramics to be electrically heterogeneous consisting of semiconducting grains and insulating grain boundaries (corresponding to high and low frequency electrical response, respectively), which played important roles in the high-temperature dielectric properties of RFeO3 ceramics.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Ceramics International - Volume 41, Issue 1, Part A, January 2015, Pages 691–698
نویسندگان
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