Paramagnetism and antiferromagnetic d–d coupling in GaMnN magnetic semiconductor

Abstract
The magnetization of Ga 1−x Mn x N (x<0.1) crystals was measured as a function of the magnetic field and temperature. Paramagnetic behavior typical of spin S=5/2 expected for Mn 2+ (d 5 ) magnetic centers was observed in the temperature range of 2 K <T<300 K . On the other hand, antiferromagnetic coupling between Mn ions was clearly visible. The nearest neighbor (NN) coupling constant J NN /k B =−1.9 K was estimated from the temperature dependence of the magnetization.