Structural and complex impedance spectroscopic studies of Ni0.5Mg0.3Cu0.2Fe2O4 ferrite nanoparticle

J Mater Sci: Mater Electron

Alzahrani

et al. 2021

Polycrystalline Mg0.5Co0.5Fe1.6Al0.4O4 ferrite was prepared with sol-gel method. This sample was characterized by powder X-ray diffraction (XRD), Scanning electron microscopy, and impedance spectroscopy. X-ray diffraction analysis combined with the Rietveld refinement confirmed that the sample crystallizes in a single-phase cubic spinel structure with (SG: 3 ̅ ). Electrical conductivity obeying the Jonscher power law indicates that the prepared material exhibits semiconductor behavior, and the conduction process follows the "non-overlapping small polaron tunnelling" model between neighbors' sites. The behavior of dielectric constants such as permittivity and loss coefficient has been interpreted based on the Maxwell-Wagner's theory of interfacial polarization. The curves of imaginary parts of impedance (Z'') and modulus (M'') show a dielectric-relaxation phenomenon in the sample with activation energy near to that determined from the dc conductivity study.Nyquist plots (Z″ vs. Z') show a monotonic decrease in both grain resistance (Rg) and grain boundary resistance (Rgb) with increasing temperature such as Rgb>>Rg. This result confirms that the transport mechanism for Mg0.5Co0.5Fe1.6Al0.4O4 compound is governed by the grain boundaries effect.

supporting

confidence: 89%

Investigations of microstructural and impedance spectroscopic properties of Mg0.5Co0.5Fe1.6Al0.4O4 ferrite prepared using sol–gel method

Dabbebi

J Mater Sci: Mater Electron

Alzahrani

et al. 2021

“…This means, according to the Funke criterion [35], that the electrons hopping in the prepared samples occurs between neighboring sites. The behavior of n observed for our samples is in good agreement with the results found in some previous works [36,37]. It can be noticeable also that the s-values for the sample sintered at 1100 °C are all bigger than those resulted from the sample sintered at 900 °C.…”

Section: Resultssupporting

confidence: 92%

“…11 that, for all the temperatures, the impedance spectra shows semicircle arcs whose maxima and diameters decline with increasing temperature. The intersection with real axis of these semicircles at low frequencies (right intersect) is ascribed to the total resistance RT= Rg + Rgb, with Rg and Rgb are the grain and grain boundary resistances, respectively [36]. On the other hand, the impedance response of grain dominates at high frequencies, so Rg can be deduced from the left intersect of the semicircles with real axis.…”

Section: Resultsmentioning

confidence: 99%

Effects of Sintering Temperature on Microstructural, Magnetic, and Impedance Spectroscopic Properties of Ni0.4Cd0.3Zn0.3Fe2O4 Ferrites

Mechi

Mallah

et al. 2020

J Supercond Nov Magn

Self Cite

Ni0.4Cd0.3Zn0.3Fe2O4 ferrites have been prepared through the use of sol-gel method at 900 °C and 1100 °C. Rietveld refinements of XRD patterns indicate that the prepared samples crystallize in the cubic spinel structure. Lattice constant and grain size are found to increase with sintering temperature. Magnetic measurements show that the maximum magnetization (Ms) rises; whereas both coercivity (Hc) and remanence (Mr) decrease when increasing the sintering temperature. Frequency and temperature dependence of electrical conductivity, electrical modulus and electrical impedance have been studied using impedance spectroscopy technique. As the sintering temperature increases, the conductivity of the samples increases.The variation of imaginary part of modulus (M'') displays the presence of an electrical relaxation phenomenon and non-Debye nature. Nyquist representations have been analyzed using an electrical equivalent circuit. The obtained results reveal that the conduction mechanism of the samples is achieved basically of the grain boundary contribution.

“…4b. The Edc value expected from the slope of the plot is 0.298 eV, which is smaller than those for other materials [40][41][42], suggesting that the present sample is a good conductor.…”

Section: Electrical Conductivity Studycontrasting

confidence: 65%

Synthesis and study of impendence spectroscopy properties of La0.6Ca0.2Na0.2MnO3 manganite perovskite prepared using sol–gel method

Alresheedi

J Mater Sci: Mater Electron

Bouazizi

et al. 2020

Self Cite

La0.6Ca0.2Na0.2MnO3 manganite was prepared using sol-gel method. Rietveld refinement of XRD pattern indicates that the prepared sample crystallizes in the rhombohedral 𝑅3𝑐 structure. The impendence spectroscopy properties of the sample were studied by performing a series of measurements as a function of temperature and frequency of conductivity, dielectric constants, modulus and impedance. From these measurements, the metal-semiconductor behaviour was observed for the sample at a transition temperature of the order of 240 K. The studies of imaginary part of permittivity and tangent loss reveal that the prepared material may be a good candidate for low-frequency energy storage devices. An electrical relaxation phenomenon with non-Debye nature was observed in variations of imaginary parts of modulus and impedance. Electrical parameters deduced from the Nyquist plots analyses using an equivalent circuit reveal that the conduction process for the sample was caused due to the grain boundaries contribution.