title: Intergranular giant magnetoresistance in a spontaneously phase separated perovskite oxide.
abstract: We present small-angle neutron scattering data proving that, on the insulating side of the metal-insulator transition, the doped perovskite cobaltite La(1-x)Sr(x)CoO(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.
authors.affiliation: Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, USA.
authors.forename: J
authors.initials: J
authors.lastname: Wu
authors.forename: J W
authors.initials: JW
authors.lastname: Lynn
authors.forename: C J
authors.initials: CJ
authors.lastname: Glinka
authors.forename: J
authors.initials: J
authors.lastname: Burley
authors.forename: H
authors.initials: H
authors.lastname: Zheng
authors.forename: J F
authors.initials: JF
authors.lastname: Mitchell
authors.forename: C
authors.initials: C
authors.lastname: Leighton