Domain-wall contribution to magnetoresistance of a ferromagnetic (Ga,Mn)As layer

• Low-temperature charge-carrier transport in simple magnetoresistive nanodevices, consisted of narrow constrictions of submicron width in the epitaxial layer of a ferromagnetic (Ga,Mn)As semiconductor, has been investigated and correlated with magnetic properties of the layer. The devices containing constrictions; revealed abrupt jumps of a reduced resistance that appeared when the sweeping magnetic field crossed the regions of the coercive field of the layer magnetization. In contrast, the non-constricted reference device displayed abrupt jumps of an enhanced resistance at the same values of magnetic field. We interpret the both features, whose positions on the magnetic-field scale reflect the hysteresis loop of magnetization, as manifestation of domain wall contribution to the (Ga,Mn)As layer resistance. The negative contribution of a domain wall to the resistance in the constricted device results most likely from the suppression of the weak localization effects by a domain wall located at the constriction.

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NATURVETENSKAP  -- Fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences (hsv//eng)

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