Crystal field excitations in the lanthanide-based square lattice magnets LnKNaNbO5

We propose to study the crystal field levels in the lanthanide-based square lattice compounds LnKNaNbO5 (Ln=Pr, Nd) with a Ln=La compound used as phonon blank. The aim of the proposal is to contrast and clarify the crystal field level scheme in non-Kramers (Pr) and Kramers (Nd) members of the series. The results will facilitate modelling of our temperature and magnetic-field dependent magnetization data, and will allow us to evaluate the exchange and anisotropy energy scales characterizing these compounds.