Paramagnetic anisotropy in highhyphen;Tcsuperconductors

摘要

Magnetic alignment of RBa2Cu3O7minus;xparticles results from anisotropy in paramagnetic susceptibility, an anisotropy that differs in sign for different rare earths. Various factors contributing to this anisotropy are discussed, particularly the rarehyphen;earth singlehyphen;ion anisotropy associated with crystal fields and secondhyphen;order Stevens factors. For R=Eu, the observed anisotropy is consistent with that expected from the crystalhyphen;field splitting ofJ=1 excited levels.