Enhancement of the ferromagnetic transition temperature in self-assembled (Ga_1-xMn_x)As quantum wires

Self-assembled (Ga_1-xMn_x)As diluted magnetic semiconductor quantum wires (QWRs) were grown on GaAs (100) substrates by molecular beam epitaxy with a goal of producing (Ga_1-xMn _x)As QWRs with a high ferromagnetic transition temperature (T _c). Scanning electron microscopy and X-ray diffraction measurements showed that the grown (Ga_0.84Mn_0.16)As QWRs were straight crystals. Magnetic force microscopy images showed that the grown QWRs were symmetric single-domain particles. The magnetization curve as a function of magnetic field at 5 K indicated that the (Ga_0.84Mn_0.16)As QWRs were ferromagnetic, and the magnetization curve as a function of temperature showed that T_c was as high as 350 K. The marked increase in T_c originated from the enhancement in Quantum confinement effect resulting from the reduction in structural dimension. These results have opened a new frontier for investigations of fundamental spintronic science.