Faraday rotation of ferromagnetic (Ga,Mn)As

Faraday rotation of (Ga, Mn)As, with an Mn composition of 0.043, is presented. The measurements were performed in the fundamental absorption edge region (1.24–1.8 eV) at 10 K (ferromagnetic phase) and at room temperature (paramagnetic phase). The magnetic behaviour of (Ga, Mn)As manifests itself in the magnetic field dependence of Faraday rotation, which was found to be proportional to the magnetisation of the sample. A large Faraday rotation of 6 × 104 deg/cm (at 0.1 T, 1.55 eV) at 10 K is observed. The Verdet constant at room temperature is 8 × 10–2 deg/G·cm (1.49 eV).