Determination of incommensurate magnetic structure in a stacked triangular quantum antiferromagnet

We propose neutron powder diffraction measurements to determine the magnetic structure in hexagonal Na2BaCoP2O8, which is a rare example of a frustrated easy-axis triangular antiferromagnet. In recent neutron single-crystal diffraction on WISH we observed a rich phase diagram with a succession of phases in applied longitudinal field, including a magnetization plateau phase and a phase with a field-dependent incommensurate propagation vector. In zero field the magnetic propagation vector corresponds to a three-sublattice in-plane order with an incommensurate propagation between layers, however the magnetic structure could not be solved in detail due to complexities in correcting the single crystal time-of-flight diffraction peak intensities. Here we propose to collect a powder diffraction pattern to obtain a reliable and quantitative parameterization of the zero-field magnetic structure to distinguish between competing magnetic structure models and also determine the absolute value of the ordered moment.