(La1-xBax)(Zn1-xMnx)AsO: A two-dimensional 1111-type diluted magnetic semiconductor in bulk form

We report the synthesis and characterization of a bulk diluted magnetic semiconductor (La1-xBax)(Zn1-xMnx)AsO (0 <= x <= 0.2) with a layered crystal structure identical to that of the 1111-type FeAs superconductors. No ferromagnetic order occurs with (Zn,Mn) substitution in the parent compound LaZnAsO without charge doping. Together with carrier doping via (La,Ba) substitution, a small amount of Mn substituting for Zn results in ferromagnetic order with T-C up to similar to 40 K, although the system remains semiconducting. Muon spin relaxation measurements confirm the development of ferromagnetic order in the entire volume, with the relationship between the internal field and TC consistent with the trend found in (Ga,Mn) As and the 111-type Li(Zn,Mn) As and the 122-type (Ba,K)(Zn,Mn)(2)As-2 systems.