ANTIFERROMAGNETICALLY COUPLED CLUSTERS AND SUPERCONDUCTORS IN PULSED MAGNETIC-FIELDS

Pulsed field differential magnetization, dM/dB, and Faraday rotation m easurements are reviewed in selected dilute magnetic semiconductors wh ich required fields above 30 T for determining the antiferromagnetic e xchange interactions between isolated pairs of magnetic ions or large clusters. In some cases, nonequilibrium effects result in a narrowing (or broadening) of the peaks in dM/dB at the level crossing which prod uce the magnetization steps at high fields. Similar measurements on a molecular ferric wheel cluster of 10 Fe3+ ions are also discussed. Cri tical field measurements in K3C60 and Rb3C60 and other superconductors are briefly summarized. The pulsed field user facility is outlined.