(Sr, Na)( Zn, Mn)(2)As-2: A diluted ferromagnetic semiconductor with the hexagonal CaAl2Si2 type structure

A new diluted ferromagnetic semiconductor (Sr, Na)(Zn, Mn) As-2(2) is reported, in which charge and spin doping are decoupled via Sr/Na and Zn/Mn substitutions, respectively, being distinguished from classic (Ga, Mn) As, where charge and spin doping are simultaneously integrated. Different from the recently reported ferromagnetic (Ba, K)(Zn, Mn) 2As2, this material crystallizes into the hexagonal CaAl2Si2 type structure. Ferromagnetism with a Curie temperature up to 20 K has been observed from magnetization. The muon spin relaxation measurements suggest that the exchange interaction between Mn moments of this new system could be different from the earlier diluted magnetic semiconductors (DMS) systems. This system provides an important means for studying ferromagnetism in DMS.