Very large magnetoresistance in lateral ferromagnetic (Ga,Mn)as wires with nanoconstrictions.
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%.
Rüster
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Physikalisches Institut (EP3), Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany.
Borzenko
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T
Gould
C
C
Schmidt
G
G
Molenkamp
L W
LW
Liu
X
X
Wojtowicz
T J
TJ
Furdyna
J K
JK
Yu
Z G
ZG
Flatté
M E
ME