Anomalies in electrical and dielectric properties of nanocrystalline Ni-Co spinel ferrite

Journal Article · Mon Aug 04 00:00:00 EDT 2008 · Materials Research Bulletin

DOI:https://doi.org/10.1016/j.materresbull.2007.09.001· OSTI ID:21144079

Kamble, R B ^[1]

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1. Novel Materials Research Laboratory, Department of Physics, University of Pune, Ganeshkhind, Pune 411 007, MS (India)

Nanocrystalline Ni-substituted cobalt ferrite sample is prepared by chemical co-precipitation method. X-ray diffraction and scanning electron microscopy techniques are used to obtain structural and morphological characterizations. Nanocrystalline nature is clearly seen in SEM picture. Variation of electrical resistivity as a function of temperature in the range 300-900 K is investigated. ln {rho} versus 1/T plot shows four break resulting into five regions in 300-900 K temperature range of measurements. The magnetic transition temperature of the sample is determined from resistivity behavior with temperature. The activation energy in different regions is calculated and discussed. Variation of dielectric constant ({epsilon}') with increasing temperature show more than one peak; one at around 773 K and other around 833 K, which is unusual behavior of ferrites. The observed peaks in {epsilon}' variation with temperature show frequency dependence. Electrical and dielectric properties of Ni{sub 0.4}Co{sub 0.6}Fe{sub 2}O{sub 4} sample show unusual behavior in the temperature range 723-833 K. To our knowledge, nobody has discussed anomalous behavior in the temperature range 723-833 K for Ni{sub 0.4}Co{sub 0.6}Fe{sub 2}O{sub 4}. The possible mechanism responsible for the unusual electrical and dielectric behavior of the sample is discussed.

• OSTI ID: 21144079
• Journal Information: Materials Research Bulletin, Vol. 43, Issue 8-9; Other Information: DOI: 10.1016/j.materresbull.2007.09.001; PII: S0025-5408(07)00403-5; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0025-5408
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ACTIVATION ENERGY
COBALT COMPOUNDS
COPRECIPITATION
CRYSTALS
DIELECTRIC MATERIALS
ELECTRIC CONDUCTIVITY
FERRITES
NANOSTRUCTURES
NICKEL COMPOUNDS
PERMITTIVITY
SCANNING ELECTRON MICROSCOPY
SPINELS
SYNTHESIS
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0273-0400 K
TEMPERATURE RANGE 0400-1000 K
TRANSITION TEMPERATURE
X-RAY DIFFRACTION