Phase transition in ferromagnetic transverse spin-1/2 Ising multilayers

The critical behavior of ferromagnetic transverse spin-1/2 Ising multilayer s consisting of two different ferromagnetic materials A and B and presentin g a sandwich structure in the form ABA, is examined using the effective fie ld theory. This method takes into consideration the fluctuations of the eff ective field, and is based on a probability distribution of random variable s which correctly accounts for all the single site kinematic relations. The critical temperature of the system is studied as a function of the thickne ss of the constituents in a multilayer and of exchange coupling in each mat erial. A critical value of the interface exchange coupling above which the interface magnetism appears is found. The effects of the transverse field, the interface exchange coupling, and surface exchange coupling on the criti cal behavior of the system are also investigated.