Excitonic Zeeman effect in the zinc-blende II-VI diluted magnetic semiconductors Cd1-xYxTe (Y = Mn, Co, and Fe) -: art. no. 155201

The sp-d exchange constants (N(0)alpha and N(0)beta) of the zinc-blende diluted magnetic semiconductors Cd1-xMnxTe, Cd1-xCoxTe, and Cd1-xFexTe are deduced from the huge excitonic Zeeman effect observed in wavelength-modulated reflectivity spectra, supplemented with magnetization measurements with a superconducting quantum interference device magnetometer. The Zeeman spectra recorded in magnetic fields (H) up to 60 kG, and temperatures (T) down to 1.8 K clearly reveal the Van Vleck paramagnetism of Cd1-xFexTe: in contrast, Cd1-xMnxTe and Cd1-xCoxTe display a Brillouin-function-like (H/T) dependence of their excitonic Zeeman components associated with spin 5/2 and 3/2 ground states of Mn2+ and Co2+, respectively. The antiferromagnetic d-d interaction between the magnetic ions, displayed in the Zeeman data, is mainly limited to nearest-neighbor Mn2+ ions, whereas it is significantly stronger for Co2+ than for Mn2+ and extends to more distant neighbors.