Electrical properties and scaling behaviour of rare earth based Ho{sub 2}CoZrO{sub 6} double perovskite ceramics

Journal Article · Sat Dec 15 00:00:00 EST 2012 · Materials Research Bulletin

DOI:https://doi.org/10.1016/J.MATERRESBULL.2012.09.028· OSTI ID:22215669

Dutta, Alo; Sinha, T. P. ^[1]

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1. Department of Physics, Bose Institute, 93/1, Acharya Prafulla Chandra Road, Kolkata 700 009 (India)

Graphical abstract: The X-ray diffraction analysis suggests that the compound crystallizes in monoclinic phase at room temperature with β = 108.51 ± 0.021° (a = 8.1858 ± 0.0023 Å, b = 5.2599 ± 0.0027 Å, c = 7.9874 ± 0.0031 Å) and cell volume = 324.17 Å{sup 3}. The SEM image indicates the uniformity of the grains in the samples. The grain size of the microstructure of HCZ is found to be ∼0.48 μm on average. Display Omitted Highlights: ► The conduction mechanism in HCZ may be due to hopping of small polaron. ► The material shows semiconducting behaviour. ► Conductivity obeys Jonscher's power law with high frequency dispersion. ► Both long-range and localized relaxation are present. -- Abstract: The Ho{sub 2}CoZrO{sub 6} (HCZ) double perovskite has been prepared in polycrystalline form by solid state reaction technique. The analysis of the X-ray powder diffraction pattern indicates that the crystal structure is monoclinic at room temperature with cell parameters a = 8.1858 ± 0.0023 Å, b = 5.2599 ± 0.0027 Å, c = 7.9874 ± 0.0031 Å and β = 108.51 ± 0.021°. The compound shows significant frequency dispersion in its dielectric properties. The Cole–Cole model is used to determine the polydispersive nature of dielectric relaxation. The scaling behaviour of dielectric loss and imaginary electric modulus suggest that the relaxation describe same mechanism at various temperatures. Impedance data presented in the Nyquist plot (Z″ versus Z′) are used to identify an equivalent circuit and to know the bulk and interface contributions. The complex impedance analysis of HCZ exhibits the appearance of both the grain and the grain-boundary contribution. The frequency dependent conductivity spectra follow the universal power law. The magnitude of the activation energy indicates that the carrier transport is due to the hopping conduction.

• OSTI ID: 22215669
• Journal Information: Materials Research Bulletin, Vol. 47, Issue 12; Other Information: Copyright (c) 2012 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
CERAMICS
DIELECTRIC MATERIALS
DIELECTRIC PROPERTIES
DISPERSIONS
EQUIVALENT CIRCUITS
FREQUENCY DEPENDENCE
GRAIN BOUNDARIES
GRAIN SIZE
MONOCLINIC LATTICES
PEROVSKITE
POLYCRYSTALS
RARE EARTHS
RELAXATION
SCANNING ELECTRON MICROSCOPY
SPECTROSCOPY
SYNTHESIS
X-RAY DIFFRACTION