TRADE-OFF BETWEEN INCREASED SIZE AND INCREASED BROADENING OF MAGNETO-OPTIC EFFECTS IN CERIUM AND URANIUM SYSTEMS

Abstract f -electron magnetic ordering and associated magneto-optic effects depend on a complicated interplay of the degree of localization in real and energy space as affected by the coulomb interaction with p d band electrons and within the f -electrons. This interplay reflects the mixed and fluctuating nature of the f configuration. A relatively simple way to try to assess the resulting trade-off of size and broadening of magneto-optic effects, capturing some gross effects of correlations ( f - f coulomb repulsion), is to use the LDA + U (coulomb repulsion energy) theory of Anisimov et al . We report the change this gives from our previous LDA results in comparison to the experiments of Schoenes and coworkers for CeSb, CeTe, UTe, and US; and we discuss our view as to the apparent shortcomings of the LDA + U results. In assessing the prospects for an optimized trade-off of size and broadening of magneto-optic effects, calculations of hydrostatic pressure effects may be quite valuable. We discuss how the use and understanding of pressure effects can provide a paradigm for the variation of magnetic ordering and associated magneto-optic behavior possible between different compounds and alloys at ambient conditions.