New diluted ferromagnetic semiconductor with curie temperature up to 180 k and isostructural to the '122' iron-based superconductors

Diluted magnetic semiconductors have received much attention due to their potential applications for spintronics devices. A prototypical system (Ga,Mn)As has been widely studied since the 1990s. The simultaneous spin and charge doping via hetero-valent (Ga 3+,Mn 2+) substitution, however, resulted in severely limited solubility without availability of bulk specimens. Here we report the synthesis of a new diluted magnetic semiconductor (Ba 1-x K x)(Zn 1-y Mn y) 2 As 2, which is isostructural to the 122 iron-based superconductors with the tetragonal ThCr 2 Si 2 (122) structure. Holes are doped via (Ba 2+, K 1+) replacements, while spins via isovalent (Zn 2+,Mn 2+) substitutions. Bulk samples with x=0.1-0.3 and y=0.05-0.15 exhibit ferromagnetic order with T C up to 180 K, which is comparable to the highest T C for (Ga,Mn)As and significantly enhanced from T C up to 50 K of the '111'-based Li(Zn,Mn)As. Moreover, ferromagnetic (Ba,K)(Zn,Mn) 2 As 2 shares the same 122 crystal structure with semiconducting BaZn 2 As 2, antiferromagnetic BaMn 2 As 2 and superconducting (Ba,K)Fe 2 As 2, which makes them promising for the development of multilayer functional devices.