Exchange Coupling in Magnetic Semiconductor Multilayers and Superlattices

Abstract

The study of ferromagnetic semiconductors continues to be of great interest because of their potential for spintronic devices. While there has been much progress in our understanding of ferromagnetic semiconductor materials particularly of the canonical IIIV system Ga1−xMnxAs many issues still remain unresolved. One of these is the nature of interlayer exchange coupling in GaMnAs-based multilayers, an issue that is important from the point of view of possible spintronic applications. In this connection, it is important to establish under what conditions the interlayer exchange coupling between successive GaMnAs layers is antiferromagnetic or ferromagnetic, since manipulation of such interlayer exchange coupling can then be directly applied to achieve giant magnetoresistance and other devices based on this material. In this review we will describe magneto-transport, magnetization, and neutron reectometry experiments applied to two types of GaMnAs-based multilayer structures superlattices and tri-layers consisting of GaMnAs layers separated by non-magnetic GaAs spacers. These measurements serve to identify conditions under which AFM coupling will occur in such GaMnAs/GaAs multilayer systems, thus providing us the information which can be used for manipulating magnetization (and thus also giant magnetoresistance) in structures based on the ferromagnetic semiconductor GaMnAs.

Ferrimagnetism in the Heisenberg–Ising bilayer with magnetically non-equivalent planes

“…As far as the ferromagnetic bilayers with antiferromagnetic couplings are concerned, there are only very few theoretical works dealing with this problem [34][35][36][37] or a similar case of multilayers [38,39], to the best of our knowledge. Let us mention the existence of some recent interesting experimental realizations of the systems in question based on semiconducting compounds, both with and without dilution [40][41][42][43][44][45]. In order to fill the gap, the present paper aims at examining the thermodynamics of the anisotropic Heisenberg-Ising bilayer with antiferromagnetic interplanar coupling.…”

Thermal Annealing Effect on GaSb Thin Films Deposited on Si (001) for Assembly of GaSb/Mn Multilayer Systems at Room Temperature

“…[8][9][10][11][12] Interlayer interaction properties have been explored in the case of multilayer systems based on magnetic materials (ferromagnetic metals, diluted magnetic semiconductors-DMS, or ferromagnetic semiconductors) over non-magnetic semiconductors. 10,13 This is because it is widely know that the ferromagnetism of GaMnAs is produced through the charge carriers coming from the Mn ions, whose carrier density variation controls its magnetic properties. [14][15][16][17] DMS materials based on GaMnAs and GaMnSb are present as promising materials for the development of applications in spintronics, although its critical temperature or Curie temperature (Tc) is low (190 K for the GaMnAs and 25 K for the GaMnSb).…”