Crystal Field Interaction and Magnetic Order in GdBa2Cu3O7

M. T. CAUSA; C. FAINSTEIN; G. NIEVA; R. SANCHEZ; L. B. STEREN; M. TOVAR; R. D. ZYSLER; D. C. VIER; S. SCHULTZ; S. B. OSEROFF; Z. FISK; J. L. SMITH

Congreso; IX Winter Meeting on Low Temperature Physics; 1988

We report experimental data on the crystal field interaction of Gd ions with their environment in Gd/sub x/Eu/1-x/Ba/sub 2/Cu/sub 3/O/sub 7/. The ESR spectrum and a Schotiky anomaly in the specific heat of dilute samples indicate the existence of a crystal field splitting of the /sup 8/S/sub 7/2/ ground state of the Gd/sup 3 +/ ions of about 1.5K. Since the single ion energies involved are of the same order of magnitude as the energies associated with the magnetic ordering of the Gd moments in GdBa/sub 2/Cu/sub 3/O/sub 7/ (T/sub N/ = 2.24K) we analyze the effects of the crystal field interaction on the magnetic transition. 10 refs., 4 figs.