Magnetic domain characterizations of anisotropic-shaped MnAs nanoclusters position-controlled by selective-area metal-organic vapor phase epitaxy

The authors report the buildup fabrication and magnetic domain characterizations of anisotropic-shaped MnAs nanoclusters position-controlled on partially SiO2-masked GaAs (111)B substrates by selective-area metal-organic vapor phase epitaxy. Magnetic force microscopy reveals that both the symmetric- and anisotropic-shaped nanoclusters show spontaneous magnetization at room temperature. Some of the nanoclusters show a single magnetic domain, in which magnetized directions are along one of the a-axes of NiAs-type MnAs, after the external magnetic fields up to 3500 Gauss are applied in-plane. The magnetic domains are well controlled by introducing both magnetocrystalline and shape magnetic anisotropies in the anisotropic-shaped nanoclusters