MBE growth process of ferromagnetic MnAs on Si(1 1 1) substrates

Abstract

We have studied initial growth process of metallic ferromagnetic MnAs thin films on Si(1 1 1) substrates by molecular beam epitaxy (MBE). MBE Growth study was performed under a variety of conditions (i.e. As 4/Mn flux ratio, substrate temperature T sub). A nearly two-dimensional growth process took place at T sub≈350° C, under a relatively small As 4/Mn flux ratio (≈1.2), and eventually resulted in the formation of smooth surface. When the As 4/Mn flux ratio was increased at a fixed T sub (≈350°C) or T sub was increased at a fixed As 4/Mn flux ratio (≈1.2), the growth mode of MnAs turned to three-dimensional resulting in the formation of islands. Structural characterizations and magnetization properties are presented and the results are discussed in relation to the growth process.