Intergranular Giant Magnetoresistance in a Spontaneously Phase Separated Perovskite Oxide

J. Wu, J. W. Lynn, C. J. Glinka, J. Burley, H. Zheng, J. F. Mitchell, and C. Leighton

Phys. Rev. Lett. 94, 037201 – Published 25 January 2005

Abstract

We present small-angle neutron scattering data proving that, on the insulating side of the metal-insulator transition, the doped perovskite cobaltite ${L a}_{1 - x} {S r}_{x} {C o O}_{3}$ phase separates into ferromagnetic metallic clusters embedded in a nonferromagnetic matrix. This induces a hysteretic magnetoresistance, with temperature and field dependence characteristic of intergranular giant magnetoresistance (GMR). We argue that this system is a natural analog to the artificial structures fabricated by depositing nanoscale ferromagnetic particles in a metallic or insulating matrix; i.e., this material displays a GMR effect without the deliberate introduction of chemical interfaces.

Received 9 July 2004

DOI:https://doi.org/10.1103/PhysRevLett.94.037201

Authors & Affiliations

J. Wu¹, J. W. Lynn², C. J. Glinka², J. Burley³, H. Zheng³, J. F. Mitchell³, and C. Leighton^1,*

¹Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, USA
²NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
³Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA

^*Corresponding author. Electronic address: leighton@umn.edu

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Vol. 94, Iss. 3 — 28 January 2005

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