Effects of the anion ordering superlattice on ‘the rapid oscillations’ in (TMTSF)2X

A novel type of magnetic oscillatory phenomenon, so-called ‘the rapid oscillations’, has been observed in quasi-one dimensional organic conductors (TMTSF)2X. To clarify the effects of the anion ordering superlattice on the rapid oscillations in ClO4 salt, we made magnetotransport studies under high pressures. We found that the rapid oscillations disappear above a threshold pressure about 5kbar above which the anion ordering is thought to be suppressed. Furthermore, we found another oscillations with a longer period under high pressures. This may be ascribed to a possible change of the anion ordering superlattice wave vector.