(Ba,K)(Zn,Mn)2Sb2: A New Type of Diluted Magnetic Semiconductor

Abstract

A series of polycrystalline samples of a new diluted magnetic semiconductor (DMS) (Ba,K)(Zn,Mn)2Sb2 has been synthesized and systematically studied. The parent phase is the so-called “Zintl compound” BaZn2Sb2, a week-degenerate semiconductor with a narrow band gap of 0.2 eV. In (Ba,K)(Zn,Mn)2Sb2, the charge is doped by (Ba,K) substitution while the spin is independently doped by (Zn,Mn) substitution. (Ba,K)(Zn,Mn)2Sb2 and analogue (Ba,K)(Zn,Mn)2As2 have comparable narrow band gaps, carrier and spin concentrations. However, the former establishes a short-range spin-glass order at a very low temperature (<10 K), while the latter forms a long-range ferromagnetic ordering with a Curie temperature up to 230 K. The sharp contrast makes (Ba,K)(Zn,Mn)2Sb2 to be a touchstone for DMS theoretical models.