THE MAGNETIC-PROPERTIES OF R IN PB2SR2(R CA)CU3O8 (R=HO AND ER)/

The electronic behavior of the rare-earth ion (R) in the Pb based supe rconductors Pb2Sr2(R(1-x)Ca(x))Cu3O8, for R = Er (x = 0, 0.5) and Ho ( x = 0), has been analyzed by inelastic neutron scattering. Sharp, well -defined transitions of magnetic origin have been observed for the par ent R = Er and Ho (x = 0) compounds. Peaks, determined to be of magnet ic origin, have been assigned to crystal-field (CF) transitions within the Russell-Saunders ground multiplet. These results have been modele d using a crystal-field hamiltonian that includes intermediate-couplin g and spherical-tenser techniques. The CF potential was determined for tetragonal symmetry. The calculated parameters are similar to those d etermined for similar R in the RBa(2)Cu(3)O(7) compounds. The results of the crystal-field analyses for the parent compounds are used to cal culate the expected rare-earth contributions to the magnetic susceptib ility, and compared to experimental data where available. In contrast to the data on the parent compounds, the spectra obtained from the sup erconductor Pb2Sr2Er0.5Ca0.5Cu3O8 show only very broad features. This broadening is attributed to chemical disorder rather than to an electr onic effect.