Published online by Cambridge University Press: 15 February 2011
Single crystals and powders of vermiculite are dehydrated and then intercalated with alkali metals (K and Rb) using a two-temperature-zone furnace. The samples, originally transparent, exhibit metallic silver color upon intercalation. Our x-ray diffraction experiments indicate that the c-axis lattice constant becomes smaller after the intercalation process. A SQUID magnetometer is used to measure the magnetization of the samples as functions of temperature and magnetic field. Evidence for Pauli paramagnetism and enhancement of ferromagnetism are found in the Rb- and K-intercalated compounds, in addition to Curie paramagnetism due to iron impurities in the original vermiculite.