Magnetic and electrical-transport property variations of epitaxially grown MnAs thin films

We have studied the magnetic and electrical-transport property variations of epitaxial MnAs thin films grown on Si(001) and GaAs(001) substrates by molecular beam epitaxy as a function of the growth temperature and film thickness. All samples show a ferromagnetic behavior with the exception of MnAs/Si(001) deposited at low growth temperatures. Interestingly, the electrical-transport properties change from metallic to semiconducting on decreasing the total thickness from 300 to 20 nm for MnAs/GaAs(001) samples. These results indicate a radical change of the electronic structure of the MnAs layer. (c) 2005 American Institute of Physics.