Magnetic anisotropy in vertically aligned diluted magnetic Mn:Ge semiconductor nanowires

Abstract

Semiconductors doped with magnetic ion, the so-called diluted magnetic semiconductors, are promising candidates for spintronics. Herein, we report on magnetic anisotropy in Mn:Ge diluted magnetic semiconductor nanowires. We grew single crystal Mn:Ge nanowires vertically on a Ge substrate and found the anisotropy in ratios of orbital to spin magnetic moments in the angle-dependent x-ray magnetic circular dichroism measurements. Our further characterization indicates that this anisotropy comes from the unique characteristics of nanowires, i.e., very high aspect ratio in their shape and tensile stress along the longitudinal direction, which confine the spins along the longitudinal direction and make an easy axis in that direction.