Formation of nanoscale ferromagnetic MnAs crystallites in low-temperature grown GaAs

Abstract
3 páginas, 3 figuras, 1 tabla.We report the formation of nanosize ferromagnetic MnAs crystallites imbedded in low-temperature grown GaAs using Mn+ ion implantation and subsequent annealing. The structural and magnetic properties of the crystallites have been characterized by transmission electron microscopy, electron beam induced x-ray fluorescence, and superconducting quantum interference device magnetometry. After an optimized thermal annealing at 750 °C, MnAs crystallites of 50 nm in size are formed. These nanomagnets show room temperature ferromagnetism.This work has been supported by QUEST, an\ud NSF Science and Technology center (Grant No.\ud DMR91.20007). P.J.W. is a postdoctoral fellow of the Deutsche\ud Forschungsgemeinschaft (DFG) J.M.G. is a postdoctoral\ud fellow of the Spanish Ministry of Education and Science.Peer reviewe