Pramana

, Volume 44, Issue 4, pp L393–L396 | Cite as

Giant magnetoresistance in bulk samples of LaMnO3 with varying Mn4+ content

  • R Mahendiran
  • R Mahesh
  • A K Raychaudhuri
  • C N R Rao
Rapid Communication

Abstract

Magnetoresistance (MR) in bulk samples of LaMnO3 has been investigated by varying the Mn4+ content from 10 to 33 per cent by chemical means, without aliovalent doping. With the increase in Mn4+ content, the structure of LaMnO3 changes first from orthorhombic to rhombohedral and then to cubic and the material becomes increasingly ferromagnetic, exhibiting a resistivity maximum akin to an insulator-metal transition atTPeak, just below the ferromagneticTc. The magnitude of MR is highest in the cubic sample (with 33% Mn4+) around theTPeak, and negligible in the non-magnetic orthorhombic sample (12% Mn4+).

Keywords

Metal-nonmetal transition perovskite oxides mixed valency giant magnetoresistance 

PACS No.

72·20 

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Copyright information

© the Indian Academy of Sciences 1995

Authors and Affiliations

  • R Mahendiran
    • 1
  • R Mahesh
    • 2
  • A K Raychaudhuri
    • 1
  • C N R Rao
    • 2
  1. 1.Department of PhysicsIndian Institute of ScienceBangaloreIndia
  2. 2.Solid State and Structural Chemistry UnitIndian Institute of ScienceBangaloreIndia

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