The magnetic behavior of 5f6 ions Am3+ and Cm4+

The 5f6 ions Am3+ and Cm4+ should exhibit temperature-independent magnetic behavior (van Vleck paramagnetism) at low temperatures. There have been few reports in the literature on the magnetic behavior of these ions and, while Am3+ has been shown to exhibit the expected temperature-independent behavior, there are also reports of anomalously large effective magnetic moments. A curium-containing compound with an effective moment less than 1.6 μB has yet to be reported. This paper is a review of the available literature on the magnetic behavior of the 5f6 ions, and a discussion of the possible interpretation of the anomalous behavior exhibited by these ions. (orig.)