Effects of external magnetic field on the effective g factor of (Ga,Mn)As

With the help of time resolved magneto-optic Kerr rotation measurements， the optically induced spin precession in heavily doped diluted magnetic semiconductor Ga 0.937 Mn 0.063 As was observed. It was found that the effective g factor increases with increasing magnetic field， which is attributed to the magnetic-field-induced increase of the density of the non-localized holes. Those free holes will couple with the localized magnetic ions by p-d interactions， leading to the formation of spontaneous magnetization in Ga 0.937 Mn 0.063 As， which in turn to the enhancement of the effective g factor.