Rich magnetic phase diagram of the kagome-staircase compound Mn3 V2 O8

We report the anisotropic magnetic phase diagrams for Mn3 V2 O8, in which S=5/2 Mn2+ is found in the kagome-staircase lattice, based on magnetization and specific heat data. At low applied fields, the system first orders magnetically below Tm1≈21 K and then shows a second transition at Tm2≈15 K. In addition, a phase transition that is apparent in specific heat but not seen in magnetization is found for all field orientations, converging toward Tm2 as H→0. The magnetic behavior is highly anisotropic, and the H-T phase diagrams are quite rich, with seven distinct phases observed.