Antiferromagnetic phase transition in Cd1-xMnxSe epilayers

Neutron-diffraction spectra of molecular-beam-epitaxy-grown single-crystal zinc-blende films of Cd1-xMnxSe reveals the onset of type-III antiferromagnetic ordering (AFM-III) for x=0.70 and 0.75 at a sharp Néel temperature. The AFM-III order is long range, with correlation lengths of around 400, and the transition is of second order. This contrasts sharply with earlier studies of bulk A1-xIIMnxBVI diluted magnetic semiconductors, where only short-range AFM-III correlations are observed, evolving gradually with decreasing temperature, and saturating at correlation length values less than 70.