Cyclotron resonance in SbCl 5-GICs

Abstract

The cyclotron resonance measurement on C 36SbCl 5 and C 60SbCl 5 was made with circularly-polarized microwaves of 68 and 23 GHz at 1.3 K up to 17 kOe. The research was undertaken in respect of the orbits in the crystal hexagonal plane. In C 60SbCl 5, resonance points corresponding to hole-like masses of −0.03 and of −0.16 and to electron like masses of 0.4 – 0.7 (in units of m ∗/m , respectively) were observed. The resonances from the latter were also observed in C 36SbCl 5, and its complicated line envelope suggests it comes from many kinds of cyclotron orbits. The existence of many electron like orbits with heavy masses was also suggested by Takahashi et al. from their dHvA (de Haas-van Alphen) measurements. The compounds were believed to consist of glassy phases at temperatures lower than about 190 K, following the electron diffraction observation by Timp et al. The configuration of the intercalant in such a glassy phase is still ambiguous, so the relation of the resonance signal to the Fermi surface topology remained unexplained.