Looking for a quantum spin liquid in the BaNi₂(V_1−xP_x)₂O₈ spin 1 honeycomb system

The general magnetic characterisation of a series of materials in the BaNi2V2O8-BaNi2P2O8 layered honeycomb spin-1 system is reported. A change from dominantly 2-dimensional (2D) to dominantly 3-dimentional (3D) magnetic character is observed on progressing from the pure V to the pure P material. The change is continuous with composition in BaNi2(V1−xPx)2O8. But a variety of features in the temperature-dependent magnetic susceptibilities at low temperatures suggest that the magnetic system is complex. Although the Curie–Weiss temperature becomes less strongly negative on increasing the P content, an indication of increased competition between different types of magnetic coupling, the system does not appear to be approaching a quantum spin liquid state at low temperatures.