Towards Quantum Magnetism with Pr4+ Ions: A Crystal-Field Study*

The Pr⁴⁺ based honeycomb antiferromagnet Na₂PrO₃ has been of recent interest due to its potential to realize Kitaev interactions with rare-earth ions. In this context, the Pr⁴⁺ ion has a ⁴f₁ configuration making it a Kramers ion. The single-ion properties of Pr⁴⁺ ions were first investigated in PrO₂ and BaPrO₃, which revealed the equal importance of spin-orbit coupling and crystal-field effects, reducing the separation between the ²F_5/2 and ²F_7/2 electronic multiplets and requiring an intermediate coupling approach. Overall, few Pr⁴⁺ compounds are known. We extended these efforts to explore the single-ion properties of Pr⁴⁺ in different compounds such as Na₂PrO₃, Sr₂PrO₄, and Li₈PrO₆. We will present inelastic neutron scattering data for Sr₂PrO4 and Li₈PrO₆ and the resulting Crystal Electric Field analysis that characterize the nature of the magnetic moments in these systems.