Magnetic properties of hexagonal MnAs nanoclusters formed on GaInAs (111) surfaces by metal-organic vapor phase epitaxy

Abstract Self-assembled formation and magnetic characteristics of hexagonal MnAs nanoclusters on GaInAs/InP (1 1 1) layers have been investigated. Atomic force microscopy (AFM) shows that hexagonal MnAs nanoclusters with well-defined crystal facets are formed on GaInAs (1 1 1) A and B surfaces. The size, density and uniformity of the nanoclusters are controllable by changing the growth conditions of metal-organic vapor phase epitaxy (MOVPE). The samples with the nanoclusters on the (1 1 1) B layers show strong magnetic anisotropy. When the external magnetic fields are applied in a direction parallel to the InP (1 1 1) B wafer plane, the samples show clear ferromagnetic hysteresis curves. The observed magnetic properties indicate that the magnetic hard axis (c-axis) of the MnAs nanoclusters is perpendicular to the wafer planes.