کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1527776 1511862 2006 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Dielectric behavior and ac electrical conductivity of nanocrystalline nickel aluminate
موضوعات مرتبط
مهندسی و علوم پایه مهندسی مواد مواد الکترونیکی، نوری و مغناطیسی
پیش نمایش صفحه اول مقاله
Dielectric behavior and ac electrical conductivity of nanocrystalline nickel aluminate
چکیده انگلیسی

Nanocrystalline nickel aluminate was prepared by chemical co-precipitation, and nanoparticles having different particle size were obtained by annealing the precursor at different temperatures. The TG/DTA measurements showed thermal decomposition was a three-step process with crystallisation of the spinel phase started at a temperature 420 °C. The X-ray diffraction analysis confirmed that the specimen began to crystallise on annealing above 420 °C and became almost crystalline at about 900 °C. The particle sizes were calculated from XRD. Dielectric properties of nickel aluminate were studied as a function of the frequency of the applied ac signal at different temperatures. It was seen the real dielectric constant ɛ′, and dielectric loss tan δ decreased with frequency of applied field while the ac conductivity increased as the frequency of the applied field increased. The dielectric relaxation mechanism is explained by considering nanostructured NiAl2O4 as a carrier-dominated dielectric with high density of hopping charge carriers. The variation of ɛ′ with different particle size depends on several interfacial region parameters, which change with the average particle size.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Materials Chemistry and Physics - Volume 98, Issues 2–3, 1 August 2006, Pages 470–476
نویسندگان
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