Optically detected electron spin-flip resonance in CdMnTe

We show that the spin‐flip of electrons at neutral donors in a dilute magnetic semiconductor can be observed directly by means of optically‐detected magnetic resonance (ODMR). Spectra obtained at 105 GHz for a bulk crystal of Cd1–x Mnx Te with x = 0.005 showed strong signals with g ‐values ranging between 12 (at 4.2 K) and 35 (at 1.7 K), with magnetic resonance linewidths ranging from 0.3 Tesla to 0.1 Tesla at the lowest temperature. In energy terms, these linewidths are independent of temperature and agree with those in spin‐flip Raman spectra from the same specimen. The line broadening is caused by fluctuations in the number of manganese ions that interact with a particular donor and an analysis of this leads to a value for the donor Bohr radius of 4.5 nm. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)