Intergranular Magnetoresistance in $Sr_2FeMoO_6$ from a Magnetic Tunnel Barrier Mechanism across Grain Boundaries

Sarma, DD and Ray, Sugata and Tanaka, K and Kobayashi, M and Fujimori, A and Sanyal, P and Krishnamurthy, HR and Dasgupta, C (2007) Intergranular Magnetoresistance in $Sr_2FeMoO_6$ from a Magnetic Tunnel Barrier Mechanism across Grain Boundaries. In: Physical Review Letters, 98 (15). 157205-1-157205-4.

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Abstract

We present magnetization (M) and magnetoresistance (MR)data for a series of $Sr_2FeMoO_6$ samples with independent control on antisite defect and grain-boundary densities, which reveal several unexpected features, including a novel switching-like behavior of MR with M. These, in conjunction with model calculations, establish that the MR in $Sr_2FeMoO_6$ is dominantly controlled by a new mechanism, derived from the magnetic polarization of grain-boundary regions acting like spin valves, leading to behavior qualitatively different from that usually encountered in tunneling MR. We show that a simple and useful experimental signature for the presence of this spin-valve-type MR (SVMR) is a wider hysteresis in MR compared to that in M.

Item Type:	Journal Article
Publication:	Physical Review Letters
Publisher:	American Physical Society
Additional Information:	Copyright of this article belongs to American Physical Society.
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit Division of Physical & Mathematical Sciences > Physics
Date Deposited:	24 Jul 2008
Last Modified:	19 Sep 2010 04:48
URI:	http://eprints.iisc.ac.in/id/eprint/15232

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