X-ray photographic study of the phase transitions in KC24 single crystals

F. Rousseaux , R. Moret , D. Guérard , P. Lagrange , M. Lelaurain

An X-ray photographic study of the temperature dependence of the in-plane ordering of potassium in stage 2 KC24 single crystals was performed between 300 K and 10 K. In the disordered high temperature phase, one observes a modulation of the diffuse halo reflecting strong third-nearest neighbour correlations which develop as T is reduced. At 124 K ± 2 K long range ordering occurs and our diffraction data confirm previous studies. The present work shows, for the first time, that the diffraction patterns change drastically at about 90 K, thus revealing a change in the in-plane potassium order at low temperature.

Mots clés: graphite; intercalation compounds; long range order; potassium compounds; solid state phase transformations; X ray diffraction examination of materials; 10 to 300K; intercalation compound; X ray photographic study; phase transitions; KC sub 24; single crystals; temperature dependence; in plane ordering; modulation; long range ordering

Domaines: Articles anciens

F. Rousseaux, R. Moret, D. Guérard, P. Lagrange, M. Lelaurain. X-ray photographic study of the phase transitions in KC24 single crystals. Journal de Physique Lettres, 1984, 45 (22), pp.1111-1118. ⟨10.1051/jphyslet:0198400450220111100⟩. ⟨jpa-00232457⟩