NUMERICAL-SIMULATION OF ANTIFERROMAGNETIC SPIN-PAIRING EFFECTS IN DILUTED MAGNETIC SEMICONDUCTORS AND ENHANCED PARAMAGNETISM AT INTERFACES

A numerical simulation of the antiferromagnetic spin pairing of neighb oring magnetic ions within a diluted magnetic semiconductor is present ed. Utilizing a random distribution of the magnetic ions requires the inclusion of nearest-neighbor interactions only in order to give agree ment with the low-field bulk-magnetization properties observed experim entally. However, the latter are shown to be a relatively insensitive measure of the degree of ordering in the alloy system, and the experim ental results could equally well be accounted for by assuming apprecia ble alloy clustering. The simulations also show that there is an enhan cement in the paramagnetism associated with the interface layers in a quantum-well structure.