Optical study of spin glass-like transition in epilayers and quantum well structures containing Cd1-xMnxTe

A spin glass-like transition was studied with the use of optical spectrosco py in Cd1-xMnxTe epilayers and bulk samples with 0.24 less than or equal to x less than or equal to 0.41 and in Cd1-xMnxTe-based quantum well structur es. Transition temperatures deduced from the temperature dependence of magn etic field-induced polarization of excitonic luminescence are in good agree ment with the spin-glass transition temperatures obtained previously by dir ect measurements of the magnetization. The transition temperatures were fou nd to be insensitive to the method of crystal growth by which the samples h ad been obtained, although, in principle, conditions for clustering of Mn i ons may be different in Bridgman- and MBE-grown samples. Reduction of the d imensionality realized in Cd1-xMnxTe/Cd1-yMgyTe heterostructures hinders th e spin-glass formation, in agreement with theoretical predictions. The tran sition is also modified in the vicinity of interfaces between diluted magne tic (semimagnetic) and nonmagnetic layers in CdTe/Cd1-xMnxTe quantum wells. (C) 1999 Elsevier Science B.V. All rights reserved.