Antiferromagnetic Interlayer Exchange Coupling in Ferromagnetic GaMnAs/GaAs:Be Multilayers

Interlayer exchange coupling (IEC) between the GaMnAs layers in GaMnAs/GaAs:Be multilayer systems has been investigated using magnetotransport experiments. The observation of a stable antiparallel magnetization alignment state from the systems indicates the presence of antiferromagnetic (AFM) IEC between the GaMnAs layers. The transitions between parallel and antiparallel alignments of GaMnAs magnetic layers in the system were carefully investigated by measuring resistance change with increasing temperature under various bias magnetic fields. From the dependence of the transition temperature on bias fields, we have estimated the magnitude of AFM IEC and its temperature behavior of our GaMnAs/GaAs:Be multilayers.