The metallic phase in potassium fullerides KxC70 was researched using electrical resistivity measurements in the case of film samples and magnetic susceptibility measurements in the case of powder samples. The K concentration dependence of the electrical resistivity of the K xC70 film at 423 K showed two minima: namely, 1.0×10-1 and 6.1×10-3 Ω cm at x = 1.1 and 4.1, respectively. The temperature dependence of the resistivity of the K4C70 film showed a disordered-metallic behavior. Superconducting quantum interference device (SQUID) measurements for K 4C70 powder revealed a temperature-independent magnetic susceptibility contribution of 3.47×10-4 emu/mol. This contribution was attributed to Pauli paramagnetism, and it was also observed in electron spin resonance (ESR) measurements. Futhermore, ESR spectra for K 4C70 powder showed that the linewidth broadened with increasing temperature. It was clearly established that K4C 70 is a metallic phase in KxC70. The crystal structure of K4C70 was found to be simple tetragonal with a = 1.266 nm and c = 1.098 nm. No superconductivity was observed in K4C70 above 2 K.
|ジャーナル||Physical Review B - Condensed Matter and Materials Physics|
|出版ステータス||Published - 2003 7 1|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics