Unusual Time Dependence of Magnetization Relaxation in MBE Grown Epilayer of CdMnTe

Abstract

The temporal behavior of the magnetization due to the spin-lattice relaxation for bulk and MBE grown epilayer of CdMnTe is compared. The time dependence of the epilayer magnetization changes (dM/dt) is nonmonotonic. After the main part, a second structure appears. It can be expłained only by the assumption of energy storage and a delayed additionał rise of specimen temperature. The nature of the storage is unknown.PACS numbers: 76.30.Fc, 68.60.WmOur previous results of magnetization relaxation measurements for diluted magnetic semiconduction [1] show that the relaxation below an external magnetic field of 10 T, for CdMnTe with Mn content below 2%, is determined by the transfer of polarization to unknown defects or impurities [2]. The data for CdMnS [3] pointed out the importance of the growth process on this part of the relaxation. To check this effect we investigated materials grown by totally different methods, namely modifled Bridgman and MBE. Both samples have an Mn content of about 10%. The epilayer (Mn content 9.5% and In doping of the order of 10 19 cm-3) was grown on a GaAs substrate with a thin ZnCdTe buffer (sample #03074 CMT:In). The bulk material was undoped. It should be pointed out that for such a high (953)