Impedance spectroscopic characterization of gadolinium substituted cobalt ferrite ceramics

Journal Article · Tue Oct 28 00:00:00 EDT 2014 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4896945· OSTI ID:22308176

Ramana, C. V. ^[1]

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1. Department of Mechanical Engineering, University of Texas at El Paso, El Paso, Texas 79968 (United States)

Gadolinium (Gd) substituted cobalt ferrites (CoFe{sub 2−x}Gd{sub x}O{sub 4}, referred to CFGO) with variable Gd content (x = 0.0–0.4) have been synthesized by solid state ceramic method. The crystal structure and impedance properties of CFGO compounds have been evaluated. X-ray diffraction measurements indicate that CFGO crystallize in the inverse spinel phase. The CFGO compounds exhibit lattice expansion due to substitution of larger Gd ions into the crystal lattice. Impedance spectroscopy analysis was performed under a wide range of frequency (f = 20 Hz–1 MHz) and temperature (T = 303–573 K). Electrical properties of Gd incorporated Co ferrite ceramics are enhanced compared to pure CoFe{sub 2}O{sub 4} due to the lattice distortion. Impedance spectroscopic analysis illustrates the variation of bulk grain and grain-boundary contributions towards the electrical resistance and capacitance of CFGO materials with temperature. A two-layer heterogeneous model consisting of moderately conducting grain interior (ferrite-phase) regions separated by insulating grain boundaries (resistive-phase) accurately account for the observed temperature and frequency dependent electrical characteristic of CFGO ceramics.

• OSTI ID: 22308176
• Journal Information: Journal of Applied Physics, Vol. 116, Issue 16; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CAPACITANCE
CERAMICS
COBALT COMPOUNDS
COBALT OXIDES
CRYSTAL LATTICES
ELECTRIC CONDUCTIVITY
EXPANSION
FERRITES
FREQUENCY DEPENDENCE
GADOLINIUM ADDITIONS
GADOLINIUM IONS
GRAIN BOUNDARIES
IMPEDANCE
LAYERS
SOLIDS
SPECTROSCOPY
X-RAY DIFFRACTION