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Self-assembled In1-xMnxAs quantum dots (0.19≤=x≤=0.45) have been grown on GaAs (100) substrates by low-temperature molecular beam epitaxy. The microstructure analysis revealed that the uniformly distributed In1-xMnxAs dots have a zinc blende structure as x≤=0.38. Furthermore, all samples exhibit ferromagnetic state at 5 K, and their Curie temperatures range from 260 to 340 K varying with x. These (In, Mn)As quantum dots are promising for room-temperature spintronic devices [ABSTRACT FROM AUTHOR]

An atomically flat and uniform reaction layer of Mn(Ga)As was found to self-organize at the (Ga,Mn)As/IrMn interface by postannealing. The Mn(Ga)As layer exhibits strong ferromagnetic characteristics up to the measured 300 K. In particular, the manifested horizontal shift of field-cooled hysteresis loops shows a clear signature of exchange bias attributable to the exchange coupling between IrMn and Mn(Ga)As. Implication from composition analyses, exchange-bias effect, and thickness dependence of the Mn(Ga)As layer versus annealing conditions is also discussed. [ABSTRACT FROM AUTHOR]