beta-Cu3V2O8: Magnetic ordering in a spin-1/2 kagome-staircase lattice

The spin-1/2 Cu2+ ions in beta-Cu3V2O8 occupy the sites of a Kagome-staircase lattice, an anisotropic variant of the Kagome net: buckled layers and imbedded plaquettes of three edge-shared CuO4 squares break the ideal Kagome symmetry. Susceptibility and heat capacity measurements show the onset of short-range ordering at approximately 75 K, and a magnetic phase transition with the characteristics of antiferromagnetism at ~29 K. Comparison to the Curie Weiss theta (theta,CW = -135 K) indicates that the geometric frustration is largely relieved by the anisotropy. A ferromagnetic contribution to the magnetization below the ordering temperature and negative magnetization in zero-field cooled measurements at low fields are attributed to uncompensated spins at grain boundaries or defects.