Self-organized semiconductor surfaces as templates for nanostructured magnetic thin films

Spontaneous pattern formation during epitaxial growth or ion erosion of semiconductor wafers offers an elegant route towards large-area nanostructured surfaces. In homoepitaxy, kinetics may result in rather uniform three-dimensional islands. In the case of semiconductor heteroepitaxy, strain relief leads to the formation of nanofaceted three-dimensional crystallites, which may self-organize into quasiperiodic arrays. By tuning substrate miscut and film thickness, or growing superlattices, a variety of patterns with different symmetries can be obtained, as will be summarized for the model system of SiGe on Si(001). Since these self-organized nanostructure arrays cover the entire wafer on which they are grown, they can serve as large-area nanopatterned substrates for subsequent deposition of magnetic thin films. It will be demonstrated that such templates allow the study of correlations between magnetic and chemical interfacial roughness, as well as the influence of pattern symmetry on the magnetic anisotropy of thin Co films. Furthermore, shadow deposition of magnetic material onto specially faceted nanostructure arrays allows the fabrication of nanomagnet arrays and the study of their magnetic properties.