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Transport and magnetic properties of $Sr_2FeMo_xW{1−x}O_6$

Ray, Sugata and Kumar, Ashwani and Majumdar, Subham and Sampathkumaran, EV and Sarma, DD (2001) Transport and magnetic properties of $Sr_2FeMo_xW{1−x}O_6$. In: Journal of Physics: Condensed Matter, 13 (4). pp. 607-616.

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Abstract

We have investigated transport and magnetic properties of a series of doubleperovskite alloys in the system $Sr_2FeMo_xW_{1−x}O_6$. These compounds exhibit a metal–insulator transition as a function of doping, x. The compounds with x in the range $1.0\geq x \geq 0.3$ show metallic behaviour in the resistivity while compounds with x in the range $0.2 \geq x \geq 0$ are insulating. All compounds with $1.0 \geq x \geq 0.2$ are ferrimagnetic, while $Sr_2FeWO_6$ (x = 0) is antiferromagnetic. The magnetization (M) is shown to increase slowly with decreasing x in the range $1.0 \geq x \geq 0.3$ due to an enhanced crystallographic ordering; however,M decreases rapidly with decreasing x thereafter (x < 0.3), probably due to composition fluctuations near the critical concentration, xc. Our data suggest primarily $Fe^{3+}–(Mo, W)^{5+}$ ordering for $x \geq 0.3$, while compositions with smaller x possibly contain both $Fe^{3+}$ and $Fe^{2+}$ species inhomogeneously due to the presence of the $W^{6+}$ state. All samples with $x \geq 0.3$ show a significant amount of negative magnetoresistance, as has been observed earlier for $Sr_2FeMoO_6$ (x = 1.0).

Item Type: Journal Article
Additional Information: Copyright of this article belongs to Institute of Physics.
Department/Centre: Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited: 17 Jun 2006
Last Modified: 19 Sep 2010 04:29
URI: http://eprints.iisc.ernet.in/id/eprint/7658

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