A novel diluted magnetic semiconductor (Ca,Na)(Zn,Mn)₂Sb₂ with decoupled charge and spin dopings

We report the successful synthesis of a new diluted magnetic semiconductor (Ca,Na)(Zn,Mn)₂Sb₂. Na and Mn are doped into the parent compound CaZn₂Sb₂, which has the same crystal structure as that of "122" type iron-based superconductor CaFe₂As₂. Na substitution for Ca and Mn substitution for Zn introduce carriers and spins, respectively. Doping Mn atoms alone up to 5% does not induce any type of magnetic ordering. When both Na and Mn are co-doped, a ferromagnetic ordering with maximum T_C～10 K has been observed. Iso-thermal magnetization shows that the coercive field is up to ～245 Oe at 2 K. Below T_C, a negative magneto-resistance with MR ～12% has also been achieved.