AbstractThe synthesis of ferromagnetic particles of the size of several nm (10… 100nm) imbedded in semiconductors is of particular interest for device applications such as magnetic sensors, switches or memories based on integrated semiconductor devices. We have investigated the formation as well as the structural and magnetic properties of MnAs nanomagnets (size ≈ 20nm) in low temperature grown GaAs (LT-GaAs). The MnAs nanomagnets which show ferromagnetism at room temperature have been synthesized using ion implantation with Mn and subsequent rapid thermal annealing (RTA). To characterize these nanomagnets, we present SQUID measurements (superconducting quantum interference device), TEM analysis (transmission electron microscopy) and EDX analysis (electron beam induced x-ray fluorescence).