Photoluminescence response of a quantum well to a change in the magnetic field of the Mn δ Layer in InGaAs/GaAs heterostructures

Ferromagnetic ordering of two types (depending on the sample geometry) is found to occur in a thin Ga 1 − x Mn x As alloy layer (Mn δ layer) in heterostructures containing an InGaAs/GaAs quantum well. Singular samples in which the δ Mn layer is parallel to the (001) GaAs plane exhibit the “3/2” Bloch temperature dependence of magnetization, and vicinal samples in which the δ Mn layer deviates from the (001) GaAs plane exhibit a “percolation” ferromagnetic transition. The photoluminescence polarization of the quantum well is shown to follow changes in the magnetization of the Mn δ layer as a function of temperature according to the Bloch law in the singular samples and to a percolation law in the vicinal samples.