Faraday effect in CdMnTe nanocrystals grown by the laser deposition method

The method of laser deposition from a composite target was used to prepare Cd_1-xMn_xTe nanocrystals embedded in an SiO₂ dielectric matrix. A study of the Faraday effect in nanocrystals of this semimagnetic semiconductor revealed enhancement of this effect, compared with bulk crystals. This was attributed to an increase in the oscillator strengths of exciton transitions and to the difference between these strengths in an external magnetic field. At helium temperatures the magnetic field dependence of the Faraday rotation in the nanocrystals was linear in fields up to 200 kOe and the temperature dependence of the rotation in the range 4.2 — 30 K had a singularity associated with a transition of the nanoparticles from the paramagnetic state to a spin glass. The temperature of this transition in the investigated nanocrystals was higher than the 'cooling' point of bulk semimagnetic semiconductors.