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

We report the results of field-dependent specific-heat measurements on La1.6-xNd0.4SrxCuO4 (x = 0, 0.1, 0.2) single crystals grown by the travelling-solvent floating-zone method. Values for the electronic energy splitting (Delta) of the lowest Kramers doublet of Nd3+ 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 Nd3+ ions observed previously in the absence of an external magnetic field is reconfirmed in this experiment. This value of Delta is found to decrease with increasing Sr content (x). Further, an increase of Delta 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(perpendicular to) = 4.31 and 4.88 for x = 0 and x = 0.1 respectively. (C) 2003 Elsevier B.V. All rights reserved.