Ferromagnetism of MnAs Studied by Heteroepitaxial Films on GaAs(001)

Abstract

Thin epitaxial films of MnAs--promising candidates for the spin injection into semiconductors--are well known to undergo simultaneously a first-order structural and magnetic phase transition at 10-40 degrees C. The evolution of stress and magnetization of MnAs/GaAs(001), both measured quantitatively with our cantilever beam magnetometer at the coexistence region of alpha-MnAs and beta-MnAs, reveal an orthorhombically distorted unit cell of the ferromagnetic phase, which provides important clues on the origin of ferromagnetism in MnAs.