Structural and dielectric properties of Cr-doped Ni–Zn nanoferrites

Abstract

Cr-doped Ni-Zn ferrite nanoparticles having the general formula Ni 0.5 Zn 0.5 Cr x Fe 2−x O 4 (x = 0.1, 0.3, 0.5) were prepared by the simplified sol-gel method. The structural and dielectric properties of the samples sintered at 750 ± 5 • C were studied. X-ray diffraction (XRD) patterns confirm the single-phase spinel structure of the prepared samples. The crystallite size calculated from the most intense peak (3 1 1) using the Debye-Scherrer formula was 29-34 nm. Scanning electron microscope images showed that the particle size of the samples lies in the nanometer regime. The dielectric constant (ε r ), dielectric loss tangent (tan δ) and ac electrical conductivity (σ ac ) of nanocrystalline Cr-Ni-Zn ferrites were investigated as a function of frequency and Cr concentration. The dependence of ε r , tan δ and σ ac on the frequency of alternating applied electric field is in accordance with the Maxwell-Wagner model. The effect of Cr doping on the dielectric and electric properties was explained on the basis of cations distribution in the crystal structure.

Structural and electrical properties of chromium substituted nickel ferrite by conventional ceramic method

“…This behavior is attributed to the Maxwell-Wagner type space charge polarization which agrees with the Koop's phenomenological theory [17]. The decrease of ε with Cr content resulted in a decrease of dielectric loss [18]. At lower frequency the high value of ε is due to the predominance of the species, such as Fe 2+ ions, oxygen vacancies, grain boundary defects, interfacial distribution, etc.…”

Overlapping large polaron tunneling conductivity and giant dielectric constant in Ni0.5Zn0.5Fe1.5Cr0.5O4 nanoparticles (NPs)

“…The corresponding dielectric constant values of our sample are 44.97 and 17.37, respectively which indicates that our sample possess a higher dielectric constant which may be dependent on structure and size of the NPs and effect of PEG coating. It can also arise from synthesis condition and oxygen deficiency on the surface of the NPs [46].…”

Structural, Thermal and Dielectric Properties of Lithium Zinc Silicate Ceramic Powders by Sol-Gel Method

“…The dielectric measurements were measured in the frequency range from 100 Hz to 1 MHz using a Phase Sensitive Millimeter (PSM 1700) LCR meter. Dielectric constant (ε ) was calculated from the formula [13].…”