Magnetic properties of GaAs/δ〈Mn〉/GaAs/InxGa1 − xAs/GaAs quantum wells

The field and temperature dependences of the magnetization of GaAs/δ〈Mn〉/GaAs/InxGa1 − xAs/GaAs quantum wells with the δ〈Mn〉 layer separated from the well by a 3-nm GaAs spacer have been studied in the temperature range of 3–300 K in a magnetic field up to 6 T. An external magnetic-field-induced phase transition to a ferromagnetic state with a magnetization hysteresis loop shifted from a zero magnetic field has been found to occur at a temperature below 40 K. A theoretical model is proposed that implies the coexistence of ferromagnetically and antiferromagnetically ordered regions within the GaAs layers.