Ferromagnetism of GaMnAs studied by polarized neutron reflectometry - art.no. 121302

Polarized neutron reflectometry has been used to investigate details of spi n ordering in ferromagnetic (FM) GaMnAs/GaAs superlattices. The reflectivit y spectra measured below the Curie temperature reveal additional magnetic c ontributions to the structural superlattice Bragg peaks, clearly indicating the existence of FM interlayer correlations. Closer investigation of the m agnetic reflectivity maxima using a full polarization analysis provides dir ect evidence that the FM order is the GaMnAs layers is truly long range. Mo reover, as shown by the data, the system exhibits a strong tendency of form ing a single-domain FM arrangement, even when cooled through Tc in zero ext ernal field.