8 research outputs found
Lithographic engineering of anisotropies in (Ga,Mn)As
The focus of studies on ferromagnetic semiconductors is moving from material
issues to device functionalities based on novel phenomena often associated with
the anisotropy properties of these materials. This is driving a need for a
method to locally control the anisotropy in order to allow the elaboration of
devices. Here we present a method which provides patterning induced anisotropy
which not only can be applied locally, but also dominates over the intrinsic
material anisotropy at all temperatures
Exploiting Locally Imposed Anisotropies in (Ga,Mn)As: a Non-volatile Memory Device
Progress in (Ga,Mn)As lithography has recently allowed us to realize
structures where unique magnetic anisotropy properties can be imposed locally
in various regions of a given device. We make use of this technology to
fabricate a device in which we study transport through a constriction
separating two regions whose magnetization direction differs by 90 degrees. We
find that the resistance of the constriction depends on the flow of the
magnetic field lines in the constriction region and demonstrate that such a
structure constitutes a non-volatile memory device
Ferromagnetic GaAs/GaMnAs Core−Shell Nanowires Grown by Molecular Beam Epitaxy
GaAs/GaMnAs core−shell nanowires were grown by molecular beam epitaxy. The core GaAs nanowires were synthesized under typical nanowire growth conditions using gold as catalyst. For the GaMnAs shell the temperature was drastically reduced to achieve low-temperature growth conditions known to be crucial for high-quality GaMnAs. The GaMnAs shell grows epitaxially on the side facets of the core GaAs nanowires. A ferromagnetic transition temperature of 20 K is obtained. Magnetic anisotropy studies indicate a magnetic easy axis parallel to the nanowire axis