Doping and field effects on the lowest Kramers doublet splitting in La1.6−xNd0.4SrxCuO4−δ single crystal

Abstract We report the results of field-dependent specific-heat measurements on La 1.6− x Nd 0.4 Sr x CuO 4 ( x =0, 0.1, 0.2) single crystals grown by the travelling-solvent floating-zone method. Values for the electronic energy splitting ( Δ ) of the lowest Kramers doublet of Nd 3+ are deduced from these data by taking into account the lattice and electronic contributions and including the two-level Schottky function. The exchange-interaction-induced splitting of the lowest Kramers doublet of the Nd 3+ ions observed previously in the absence of an external magnetic field is reconfirmed in this experiment. This value of Δ is found to decrease with increasing Sr content ( x ). Further, an increase of Δ is shown to occur upon application of an external magnetic field aligned along the crystal c -axis. The analysis of these field-dependent data yields for the g -factor in the field direction the values g ⊥ =4.31 and 4.88 for x =0 and x =0.1 respectively.