Orientation and interface effects on the structural and magnetic properties of MnAs-on-GaAs hybrid structures

MnAs grows either with the (1 (1) over bar 00)prism-plane on GaAs(001), (113)A and (110) or the (0001) c-plane on GaAs(111)13 substrates. The strain state of the films determines the phase coexistence of ferromagnetic alpha- and paramagnetic beta-MnAs and their distribution in self-organized structures. The mismatch accommodation mechanisms along the a-axis of alpha-MnAs are in principle the same for all substrate orientations, while they are very different along the c-axis. Depending on the orientation the Curie temperature can exceed the value for bulk MnAs.