(Ga,Mn)As is the prototypical ferromagnetic semiconductor for spintronics devices, largely because of its rich magnetic and transport anisotropy. Until recently, the lack of local anisotropy control limited device design as all elements inherited the anisotropy of the parent layer. We report here on anisotropy control through lithographically engineered strain relaxation. By patterning the layer, we allow local and strain relaxation and controlled deformation of the crystal. Because of the strong spin orbit coupling, this leads to a new anisotropy term that can be tuned independently for each element of a compound device. We use this method to demonstrate a novel non-volatile memory element.
L. W. Molenkamp,
"Novel spintronic devices using local anisotropy engineering in (Ga,Mn)As", Proc. SPIE 7036, Spintronics, 703614 (4 September 2008); doi: 10.1117/12.798109; https://doi.org/10.1117/12.798109