The structural evolution and magnetic property of Mn-rich clusters in GeMn thin films grown at 70 °C by molecular beam epitaxy has been systematically investigated by TEM, EDS and SQUID. It was discovered that, by controlling the Mn concentration, the morphology of coherent Mn-rich clusters can be manipulated from tadpole to nanocolumn shapes. For a particular Mn concentration, the critical thickness to form coherent Mn-rich clusters at 70 °C has been identified. Magnetic measurements show a complex magnetic behavior, which is mainly related to the Mn-rich clusters or precipitates. Our results also reveal that a flat surface of the Ge buffer layer plays an important role in producing vertically aligned tadpoles and nanocolumns.
All Science Journal Classification (ASJC) codes
- Mechanics of Materials
- Mechanical Engineering
- Metals and Alloys
- Materials Chemistry