Electron paramagnetic resonance linewidths in diluted magnetic semiconductors: Cd1−xMnxTe

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Abstract
We report measurements of EPR in the magnetic semiconductors Cd1−xMnxTe and reanalyze earlier data. Experimentally we find (i) the room temperature linewidth increases as x is increased, (ii) the g value, obtained by reference to the zero of the derivative curve, is almost independent of x, (iii) each resonance line has a symmetric lineshape, and (iv) for each x the linewidth increases as T is reduced. These facts suggest that the resonances are not relaxation broadened but are, instead, inhomogeneously broadened. We model this inhomogeneity in terms of a Gaussian distribution of internal fields and show that there is a sharp change in the x dependence of the corresponding Gaussian widths at the percolation threshold. We also note that the temperature dependence of the linewidths follows an empirical form proposed earlier for metallic spin glasses.