Verwey-type transition within the Pb3Rh7−xMnxO15 solid solution

A complete solid solution was found between isostructural Pb3Mn7O15 and Pb3Rh7O15. Single-crystals of two members of the solid solution Pb3Rh7−xMnxO15 (x=1.07 and 2.26) were grown and their crystal structures were determined. The Verwey-type transition for Pb3Rh7O15 at 185 K remains with a 3% substitution of Mn for Rh but disappears with 4% substitution of Mn for Rh. The magnetic ordering temperature found for Pb3Mn7O15 at about 70 K is maintained at a 43% substitution of Rh for Mn but has disappeared for 57% substitution of Rh for Mn. The unit cell volume of this layered structure contracts with increasing x for Pb3Rh7−xMnxO15 phases, but the structure actually expands in the direction perpendicular to the layers due to increased separation between the layers.