Theoretical studies of the crystal field energy levels and EPR g factors for CeFeAsO1-xFx

摘要

The ion-based superconductor CeFeAsO1-x F-x has received much attention because this rare earth oxypnictide belongs to a new class RFeAsO1-xFx of high-T, superconductors with critical temperatures surpassed by high-T, copper oxides. Since the Ce3+ is situated near the superconducting PeAs plane, it can be used as a probe to study the influence of superconductivity on spin dynamic properties of the FeAs layer. It is important to determine the optical and magnetic properties of rare earth ion in oxypnictides. Here, based on the crystar field theory, the crystar field (CP) energy levels and electron paramagnetic resonance parameters g factors of Ce3+ in CleFeAs(1-x)F(x), are studied by diagonalizing the full energy matrix. In the calculations, the contributions of various admixtures and interactions are all considered. The results are discussed.