Electron paramagnetic resonance of Cr2+ and Cr4+ ions in CdGeAs2 crystals
Abstract
Electron paramagnetic resonance (EPR) has been used to investigate chromium ions in single crystals of CdGeAs2 grown by the horizontal gradient freeze technique. Signals from Cr2+ and Cr4+ ions were observed near 12 K. The Cr2+ ions have the 3d4 configuration with S=2 and substitute at the cadmium sites, while the Cr4+ ions have the 3d2 configuration with S=1 and substitute at the germanium sites. As a result, each impurity represents a neutral center. Both EPR spectra display the tetragonal symmetry of the lattice, which suggests that the centers most likely are not perturbed by nearby defects. The ratio of Cr2+ ions to Cr4+ ions in a particular CdGeAs2 crystal depends on the growth conditions and stoichiometry.
- Publication:
-
Journal of Applied Physics
- Pub Date:
- December 2003
- DOI:
- 10.1063/1.1629802
- Bibcode:
- 2003JAP....94.7567G
- Keywords:
-
- 76.30.Fc;
- Iron group ions and impurities