Magnetic response of Cd0.63Mn0.37Te under illumination:: Dynamic behavior of spin glass with step-like heating and cooling

The magnetic behavior of a typical diluted magnetic semiconductor Cd0.63Mn0.37Te was investigated under the unpolarized light illumination in a magnetic field. Both the zero field cooled (ZFC) and field cooled (FC) values of magnetization in Cd0.63Mn0.37Te decrease under illumination below the spin freezing temperature. This magnetic response was explained on the basis of a change in temperature of the sample under illumination, since the intrinsic photo- induced magnetic change was less than the resolution of superconducting quantum interference device magnetometer. The transient behavior observed in the FC and ZFC values of magnetization in Cd0.63Mn0.37Te was analyzed in terms of the step-like heating and cooling induced by the optical method and it was observed that the FC magnetization showed hardly any relaxation in spite of the change in temperature below the spin freezing temperature. In addition, the analysis of ZFC magnetization indicated that two types of spins coexist in the low temperature state of Cd0.63Mn0.37Te: one belongs to the freezing spin cluster and the other shows paramagnetic behavior. (C) 1999 American Institute of Physics. [S0021-8979(99)02810-8].