Physical properties of Mn oxypnictide (LaO)MnPn; Pn = P, As, Sb.

We have investigated physical properties of the layered Mn oxypnictides (LaO)MnPn; Pn = P, As, Sb. Electrical resistivity of three samples, indicting semiconducting behaviors, drastically increases with lowering temperature. The optical band gaps estimated from the diffusive reflectance are about 1.6 eV and they don't depend on pnictogen atoms even though the lattice constants widely change. Magnetizations of (LaO)MnAs and (LaO)MnSb show very weak temperature dependence with positive slope against temperature. Some magnetic order is expected to exist at higher temperature than room temperature. Consequently, the Mn oxypnictides (LaO)MnPn are magnetic semiconductors. [ABSTRACT FROM AUTHOR]