Manganese-mediated ferromagnetism in La2Fe1-xMn2xCr1-xO6 perovskite oxides

Tiwari, RM and Gadhvi, Mrudul and Nag, Abanti and Vasanthacharya, NY and Gopalakrishnan, J (2010) Manganese-mediated ferromagnetism in La2Fe1-xMn2xCr1-xO6 perovskite oxides. In: Proceedings of the Indian Academy of Sciences - Chemical Sciences, 122 (4). pp. 529-538.

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Abstract

We have investigated the structure and magnetic properties of the perovskite oxides of the formula La2Fe1-xMn2xCr1-xO6 (0 < x < 1.0). For 0 < x <= 0.5, the members adopt the orthorhombic (Pbnm) structure, where the transition metal atoms are disordered at the 4b sites and the MO6 (M = Fe, Mn, Cr) octahedra become increasingly distorted with increasing x. For 0.65 <= x < 1.0, the members adopt the rhombohedral (R-3c) structure that is similar to LaMnO3+delta (delta >= 0.1) where the MO6 octahedra are undistorted. While the magnetic properties of the latter series are largely similar to the parent LaMnO3+delta arising from the double-exchange (DE) between mixed valent Mn-III/Mn-IV, the magnetic properties of the orthorhombic members show a distinct (albeit weak) ferromagnetism (T-C similar to 200 K) that seems to arise from a Mn-III-mediated superexchange (SE) between Fe-III/Cr-III in the disordered perovskite structure containing Fe-III, Mn-III and Cr-III.

Item Type:	Journal Article
Publication:	Proceedings of the Indian Academy of Sciences - Chemical Sciences
Publisher:	Indian Academy of Sciences
Additional Information:	Copyright of this article belongs to Indian Academy of Sciences.
Keywords:	La(Fe, Mn, Cr)O-3; orthorhombic and rhombohedral perovskites; ferromagnetism; superexchange; double exchange.
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	08 Sep 2010 06:09
Last Modified:	19 Sep 2010 06:15
URI:	http://eprints.iisc.ac.in/id/eprint/32028

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