title: Very large magnetoresistance in lateral ferromagnetic (Ga,Mn)as wires with nanoconstrictions.
abstract: We have fabricated (Ga,Mn)As nanostructures in which domain walls can be pinned by sub-10 nm constrictions. Controlled by shape anisotropy, we can switch the regions on either side of the constriction to either parallel or antiparallel magnetization. All samples exhibit a positive magnetoresistance, consistent with domain-wall trapping. For metallic samples, we find a magnetoresistance up to 8%, which can be understood from spin accumulation. In samples where, due to depletion at the constriction, a tunnel barrier is formed, we observe a magnetoresistance of up to 2000%.
authors.affiliation: Physikalisches Institut (EP3), Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Rüster
authors.forename: T
authors.initials: T
authors.lastname: Borzenko
authors.forename: C
authors.initials: C
authors.lastname: Gould
authors.forename: G
authors.initials: G
authors.lastname: Schmidt
authors.forename: L W
authors.initials: LW
authors.lastname: Molenkamp
authors.forename: X
authors.initials: X
authors.lastname: Liu
authors.forename: T J
authors.initials: TJ
authors.lastname: Wojtowicz
authors.forename: J K
authors.initials: JK
authors.lastname: Furdyna
authors.forename: Z G
authors.initials: ZG
authors.lastname: Yu
authors.forename: M E
authors.initials: ME
authors.lastname: Flatté