Synthesis and properties of a new quadruple perovskite: A-site ordered PbMn3Mn4O12

► PbMn3Mn4O12 a quadruple perovskite was prepared at high pressure. ► A structural transition is seen at 380 K from space group R-3-to-Im-3. ► An antiferromagnetic transition is observed at 68 K. ► It is semiconducting with a large decrease in the conductivity near 68 K. ► The temperature dependence of the dielectric constant increases dramatically at 68 K. ► Coupling of magnetic, electric and dielectric behavior suggests multiferroicity.