Structure-property relationship in layered BaMn2Sb2 and Ba2 Mn3Sb2O2

Layered transition-metal compounds have received great attention owing to their physical properties. Here, we present the structural, electronic, thermal, and magnetic properties of BaMn2Sb2 and Ba2Mn3Sb2O2 single crystals, both with the layered structure analogous to high-temperature Cu- A nd Fe-based superconductors. While the Mn moment in the MnSb4 tetrahedral environment forms a long-range G-type antiferromagnetic (AFM) ordering in both BaMn2Sb2 (TN1≈443K) and Ba2Mn3Sb2O2 (TN1≈314K), a short-range AFM order is found in the intercalated MnO2 layer at a much lower temperature (TN2≈60K) coexisting with long-range G-type order in MnSb4 layer in Ba2Mn3Sb2O2. The directions of the ordered moments in these two magnetic sublattices of Ba2Mn3Sb2O2 are perpendicular to each other, even though the system is electrically conductive. The G-type AFM order in MnSb4 layers in both compounds is distinct from the stripe-like order in Fe-based superconductors, but the in-plane magnetic structure in MnO2 layers of Ba2Mn3Sb2O2 is found to be similar to that in the cuprates. Our study reveals the significant and distinct roles of the CuO2- A nd FeAs4-type transition metal layers in the structure and their magnetic and electronic properties.