Electron-Hole Asymmetry in the Rare-Earth Manganates: A Comparative Study of the Hole- and the Electron-Doped Materials

Sarathy, Vijaya K and Vanitha, PV and Seshadri, Ram and Cheetham, AK and Rao, CNR (2001) Electron-Hole Asymmetry in the Rare-Earth Manganates: A Comparative Study of the Hole- and the Electron-Doped Materials. In: Chemistry of Materials, 13 (3). pp. 787-795.

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Abstract

Properties of the hole-doped Ln(1-x)A(x)MnO(3) (Ln = rare earth, A = alkaline earth, x < 0.5) are compared with those of the electron-doped compositions (x > 0.5). Charge ordering is the dominant interaction in the latter class of manganates unlike ferromagnetism and metallicity in the hole-doped materials. Properties of charge-ordered (CO) compositions in the hole- and electron-doped regimes, Pr0.64Ca0.36MnO3 and Pr0.36Ca0.64MnO3, differ markedly. Thus, the CO state in the hole-doped Pr0.64Ca0.36MnO3 is destroyed by magnetic fields and by substitution of Cr3+ or Ru4+ (3%) in the Mn site, while the CO state in the electron-doped Pr0.36Ca0.64MnO3 is essentially unaffected. It is not possible to induce long-range ferromagnetism in the electron-doped manganates by increasing the Mn-O-Mn angles up to 165 and 180 degrees as in La0.33Ca0.33Sr0.34MnO3; application of magnetic fields and Cr/Ru substitution (3%) do not result in long-range ferromagnetism and metallicity. Application of magnetic fields on the Cr/Ru-doped, electron-doped manganates also fails to induce metallicity. These unusual features of the electron-doped manganates suggest that the electronic structure of these materials is likely to be entirely different from that of the hole-doped ones, as verified by first-principles linearized muffin-tin orbital calculations.

Item Type:	Journal Article
Publication:	Chemistry of Materials
Publisher:	The American Chemical Society
Additional Information:	Copyright of this article belongs to The American Chemical Society.
Keywords:	Colossal Magnetoresistance;Giant Magnetoresistance;Manganites;Transition;Perovskite;La1-Xcaxmno3;Transport;Disorder;Crystal;Lamno3.
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	03 Jun 2009 05:04
Last Modified:	01 Jul 2011 09:09
URI:	http://eprints.iisc.ac.in/id/eprint/16878

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