Effect of self-organized quantum structures on spinglass and metal-insulator transition in CdMnTe single crystals

Vapour phase grown Cd1-xMnxTe crystals with x=0.2,0.3,0.4 and 0.5 were found to contain self-organized quantum structures as revealed by SEM micrographs. ac Susceptibility measurements were carried out in the temperature range 14-300 K at 313 Hz. Both the real and imaginary parts of susceptibility showed formation of spinglass phase at low temperatures. Dark and photo current studies in the temperature range 125-450 K indicated metal-semiconductor transitions. Further, photo excitation seemed to enhance the metal-semiconductor phase transition temperature. Both the spinglass formation and metal semiconductor transition temperatures observed in the present CdMnTe samples were much higher than the earlier reported values and are attributed to the presence of self-organized microstructures. (C) 2005 Elsevier B.V. All rights reserved.