کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
8153607 1524767 2018 45 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Elucidation of structural, vibrational and dielectric properties of transition metal (Co2+) doped spinel Mg-Zn chromites
موضوعات مرتبط
مهندسی و علوم پایه فیزیک و نجوم فیزیک ماده چگال
پیش نمایش صفحه اول مقاله
Elucidation of structural, vibrational and dielectric properties of transition metal (Co2+) doped spinel Mg-Zn chromites
چکیده انگلیسی
Co2+ doped Mg-Zn spinel chromite compositions Mg0.5Zn0.5-xCoxCr2O4 (0.0  ≤  x ≤ 0.5) have been synthesized by the high-temperature solid state method. Synchrotron and X-ray diffraction (XRD) studies show single-phase crystalline nature. The structural analysis is validated by Rietveld refinement confirms the cubic structure with space group Fd3m. Crystallite size is estimated from Synchrotron XRD which was found to be 30-34 nm. Energy dispersive analysis confirms stoichiometric Mg0.5Zn0.5-xCoxCr2O4 composition. Average crystallite size distribution is estimated from imaging software (Image - J) of SEM is in the range of 100-250 nm. Raman spectroscopy reveals four active phonon modes, and a pronounced red shift is due to enhanced Co2+ concentration. Increased Co2+ concentration in Mg-Zn chromites shows a prominent narrowing of band gap from 3.46 to 2.97 eV. The dielectric response is attributed to the interfacial polarization, and the electrical modulus study supports non-Debye type of dielectric relaxation. Ohmic junctions (minimum potential drop) at electrode interface are active at lower levels of doping (x < 0.2) give rise to a low-frequency semicircle as evidenced from the complex impedance analysis. The low dielectric loss and high ac conductivity of Co2+ doped Mg-Zn spinel chromites are suitable for power transformer applications at high frequencies.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Magnetism and Magnetic Materials - Volume 454, 15 May 2018, Pages 274-288
نویسندگان
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