STRUCTURE AND SPIN-GLASS PROPERTIES OF CD0.5MN0.5S DILUTED MAGNETIC SEMICONDUCTOR QUANTUM DOTS

Cd0.5Mn0.5S diluted magnetic semiconductor (DMS) quantum dots (QDs) of crystallite size ranging from 24 Angstrom to the bulk have been chemi cally synthesized using an aqueous solution precipitation method and t hermal annealing. Subsequent characterization indicates that the ''as prepared'' material is of the cubic zinc blende structure which evolve s with increasing size to the bulk hexagonal wurtzite structure. Magne tic properties of the DMS QDs have been measured with a SQUID magnetom eter. A transition from a paramagnetic to a spin-glass (SG) state at a critical temperature T-f has been observed. Size dependence measureme nts on T-f indicate a minimum size for SG formation. Relaxation in iso thermal remanent magnetization has also been measured and shows a powe r law decay.