Magnetic structure and giant magnetoresistance of ferromagnetic La1-delta Mn1-delta O3 - An example of double-exchange striction?

Cheetham, AK and Rao, CNR and Vogt, T (1996) Magnetic structure and giant magnetoresistance of ferromagnetic La1-delta Mn1-delta O3 - An example of double-exchange striction? In: Journal of Solid State Chemistry, 126 (02). pp. 337-341.

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Abstract

A neutron powder diffraction study of the structure of the rhombohedral phase of La1-deltaMn1-deltaO3 (delta = 0.04) as a function of temperature has been carried out, The crystal structure is well described at all temperatures by a model in R - 3c (a = 5.52264(5) and c = 13.3309(5) at 300 K) and the low temperature data contain magnetic contributions to the Bragg scattering due to ferromagnetic ordering below T-c similar to 200 K. The spin is canted at approximately 45 degrees from [001]. The Mn-O-Mn angle decreases on cooling to T-c, but shows a slight increase on further cooling, presumably due to the onset of a double-exchange striction effect. Resistivity and magnetization data corroborate the neutron findings and reveal an insulator to metal transition close to T-c with a negative giant magnetoresistance value of similar to 50% at this temperature. The results confirm the striking similarity between the structural, magnetic, and conducting properties of rhombohedral La1-deltaMn1-deltaO3 and those of the solid solution La(1-x)A(x)MnO(3) (x similar to 0.3)

Item Type:	Journal Article
Publication:	Journal of Solid State Chemistry
Publisher:	Academic Press
Additional Information:	Copyright of this article belongs to Academic Press.
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	12 Jan 2010 10:52
Last Modified:	19 Sep 2010 05:26
URI:	http://eprints.iisc.ac.in/id/eprint/19112

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