Super-paramagnetic blocking phenomena and room-temperature ferromagnetism in wide band-gap dilute magnetic semiconductor (Ga, Mn)N

We present computer simulations on the super-paramagnetic blocking phenomena in wide band-gap dilute magnetic semiconductors (DMSs) in particular (Ga, Mn)N. It is shown that due to the formation of magnetic nano-clusters of magnetic impurities under the spinodal decomposition, super-paramagnetic blocking temperature (T-B) of the DMS is enhanced and hysteretic magnetic response can be observed at finite temperature even if Curie temperature of the whole system is nearly zero. T-B higher than room temperature can be expected and the blocking phenomena explains reported ferromagnetic behaviour of wide band-gap DMS at high temperature.