Interlayer exchange coupling in short period GaMnAs/GaAs superlattices

The low dimensional structures containing III-V ferromagnetic semiconductor s were intensively investigated in the last few years because of the variet y of their potential applications. The aim of the present work was to study the interlayer exchange coupling in the short period GaMnAs/GaAs superlatt ices containing 16 or 8 GaMnAs monolayers. Samples with the magnetic layers corresponding to the mixed crystal composition with 5% or 6% of Mn were gr own by MBE technique and characterized by both high-resolution X-ray diffra ction and Raman scattering methods. Folded acoustic phonons were observed f or the first time for this particular quantum system in the Raman scatterin g spectra. The interlayer exchange coupling in selected superlattices. was investigated by both elastic neutron scattering (diffraction) and polarized neutron reflectivity measurements. Presence of the smooth interfaces and t he stability of the superlattice period were confirmed by neutron reflectom etry data. Ferromagnetic correlation of the magnetization vector in subsequ ent GaMnAs magnetic layers was demonstrated by both experimental methods.