Magnetism and Crystal Fields in Ternary Superconductors

Abstract

Ternary compounds exhibiting superconductivity have been under intensive investigation in the last few years, and some of the related properties were reviewed in the last proceedings of this conference series by several authors.^1–3 Among the more stimulating phenomena is the observation that many of these materials exhibit superconductivity even when one of the constituents is strongly magnetic, such as a rare earth (RE) ion. This is in sharp contrast to the behavior usually found in binary compounds, where very small concentrations of magnetic ions are adequate to totally suppress the superconducting transition. In the ternary materials, the presence of large concentrations of magnetic ions has also provoked renewed interest in questions concerning the ways in which superconductivity and magnetism affect one another, and whether the two types of order can simultaneously occur. Much of the work carried out in the past on the coexistence question utilized pseudobinary systems, and it is now generally believed that those experiments showed the coexistence of superconductivity with spin-glass type ordering, rather than with true, long-range magnetism.⁴ The ternary compounds, being structurally homogeneous, will not show that behavior, and so are much more ideally suited to stimulate and test theoretical predictions on the interaction between magnetism and superconductivity.

Work supported by the U.S. Department of Energy.