Epitaxial Fe films and structures

摘要

Iron film growth conditions and films properties on A- and R- sapphire surfaces were investigated. The best growth conditions were achieved at temperatures about 250 - 300°C. A 10 nm Mo seed layer on the A-sapphire surface improves Fe film morphology and film roughness becomes less than 1 nm. As a result epitaxial Fe (011) films with high residual electron mean free paths (about 0.5 mkm) were grown on the A-sapphire surface. These films can be used for ballistic ferromagnetic planar nanostructures fabrication.The magnetic domain configuration of epitaxial iron nanostructures shaped as bridges and crosses depending on the orientation relative to the easy magnetic axis Fe [100] was examined. If the long side of the bridge is directed along the easy magnetic axis, the single domain structure state is easily reached up to maximum structure width about 2 mkm. A stripe domain structure can be observed when the easy magnetic axis is normal to the long rectangular structure axis. The structure orientation at some angle with the easy magnetic axis leads to a magnetic domain configuration along the easy axis is independent of the structure size down to a structure width ~0.5 mkm and depends only on the easy axis direction. The single domain state can be obtained in structures with a width less than 0.5 mkm. The cross-type structures may have only a two-fold symmetry magnetic configuration. Trapeziform domains were found in structures directed along the hard Fe magnetic axis.