  A new diluted ferromagnetic semiconductor (Sr,Na)(Zn,Mn)2As2 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 & 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 to the earlier DMS systems. This system provides an important means
for studying ferromagnetism in diluted magnetic semiconductors.
