Doping induced high temperature transport properties of Ca1−xGdxMn1−xNbxO3 (0 ≤x ≤ 0.1)

Nag, Abanti and D'sa, Florita and Shubha, V (2015) Doping induced high temperature transport properties of Ca1−xGdxMn1−xNbxO3 (0 ≤x ≤ 0.1). Materials Chemistry and Physics, 151. pp. 119-125. ISSN 0254-0584

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Abstract

The co-substituted Ca1_xGdxMn1_xNbxO3 (0 � x � 0.1) perovskite are synthesized by solid state reaction. Rietveld refinement analysis of powder XRD confirms orthorhombic structure (Pnma) for all the compositions. The lattice parameters and cell volume increase gradually with dopant concentration. The thermopower and electrical resistivity (x � 0.08) decrease with increase of dopant concentration i.e. with increasing the Mn3þ ions having eg 1 electrons. At higher dopant concentration (x > 0.08) the resistivity starts increasing due to the reduced mobility of charge carriers. The enhanced octahedral distortion in the crystal lattice of co-substituted Ca1�xGdxMn1�xNbxO3 is responsible for the reduction of charge carrier mobility. The transport mechanism of charge carriers are explained in the framework of Mott's small polaron hopping mechanism. The highest power factor of 225 mW m�1 K�2 and ZT of 0.15 are obtained at x ¼ 0.04 composition at 800 K.

Item Type:	Article
Additional Information:	Copyright to this article belongs to M/s. Elsevier Science
Uncontrolled Keywords:	Oxides;Crystallography;Transport properties;Electrical conductivity;Thermoelectric effects
Subjects:	CHEMISTRY AND MATERIALS > Chemistry and Materials (General)
Depositing User:	Ms. Alphones Mary
Date Deposited:	09 Oct 2015 06:10
Last Modified:	09 Oct 2015 06:10
URI:	http://nal-ir.nal.res.in/id/eprint/12400

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