Nanoscale inhomogeneities: A new path toward high Curie temperature ferromagnetism in diluted materials

作者：Chakraborty Akash; Bouzerar Richard; Kettemann Stefan; Bouzerar Georges^*

来源：Physical Review B, 2012, 85(1): 014201.

DOI：10.1103/PhysRevB.85.014201

Room-temperature ferromagnetism has been one of the most sought after topics in today%26apos;s emerging field of spintronics. It is strongly believed that defect-and inhomogeneity-free sample growth should be the optimal route for achieving room-temperature ferromagnetism, and huge efforts are made in order to grow samples as %26quot;clean%26quot; as possible. However, until now, in the dilute regime it has been difficult to obtain Curie temperatures larger than that measured in well annealed samples of (Ga,Mn)As (similar to 190 K for 12% doping). In the present work, we propose an innovative path to room-temperature ferromagnetism in diluted magnetic semiconductors. We theoretically show that even a very small concentration of nanoscale inhomogeneities can lead to a tremendous boost of the critical temperatures: up to a 1600% increase compared to the homogeneous case. In addition to a very detailed analysis, we also give a plausible explanation for the wide variation of the critical temperatures observed in (Ga,Mn)N and provide a better understanding of the likely origin of very high Curie temperatures measured occasionally in some cases. The colossal increase of the ordering temperatures by nanoscale cluster inclusions should open up a new direction toward the synthesis of materials relevant for spintronic functionalities.

• 出版日期2012-1-19