Magnetic Properties of Short Period InGaMnAs/InGaAs Superlattices
  We have observed a paramagnetic-to-ferromagnetic phase transition in short period InGaMnAs/InGaAs superlattices. The thicknesses of magnetic InGaMnAs layers in the structures studied was chosen to be 4 or 8 molecular layers (12 \AA or 24 \AA). The nonmagnetic InGaAs spacer layers are 12 \AA thick. The In content of InGaMnAs and InGaAs layers was chosen in such a way that magnetic layers were: deep potential wells, high potential barriers or shallow potential wells. For superlattices with 8 monolayer thick InGaMnAs magnetic layers and 4 monolayer thick InGaAs nonmagnetic spacers the temperatures of paramagnetic-to-ferromagnetic phase transition do not depend on the band offsets between InGaMnAs and InGaAs adjusted by the In content. 
J. Sadowski, R. Mathieu, P. Svedlindh, J. Kanski, M. Karlsteen, K.   Swiatek, and J. Z. Domagala