Crystal field effect on the f-levels of R1+xBa2−xCu3O6+δ (R=Sm,Nd)

Abstract Infrared (IR) spectroscopy has been used to observe the crystal field (CF) levels of the five lowest J multiplets of Sm3+ in regular D4h symmetry sites in Sm1+xBa2−xCu3O6+δ. From a fit to these levels, we have calculated a set of the CF parameters. Doublet features in the IR spectra have been tentatively associated with the anisotropic Sm–Cu exchange interaction. Theoretical analysis, using the superposition model, as well as density functional based ab initio calculations of the CF interaction have indicated that some of the IR bands arise from the Sm3+ ions occupying the C4v symmetry Ba sites. The magnetic susceptibility of single-crystalline REBa2Cu3O6 (Re=Nd, Sm) has been measured and compared with calculations using the phenomenological CF parameters.