Quadrupolar interactions in Pr compounds: PrFe4P12 and PrBa2Cu3O6

Abstract

We examine trivalent Pr crystal field models with near-degeneracy of the two lowest crystal field levels, where interaction-induced quadrupolar and dipolar moments are as important as the permanent moments of the crystal field ground state. We find that the Gamma1-Gamma4 level scheme yields a successful description of the antiferroquadrupolar ordering of PrFe4P12. For PrBa2Cu3O6, we argue that quadrupolar interaction is important for understanding the Pr ordering transition at 11K.

One of the figures, and a few sentences replaced. 8 pages, 5 figures, iopart submitted to the Proceedings of the conference on "Advances in the Physics of f-electron Systems (JAERI Tokai, Japan), accepted for publication in J. Phys.: Condensed Matter