Magnetic and electronic properties of pure and alkali-doped C60 crystals

✍ Scribed by H. Suematsu; Y. Murakami; T. Arai; K. Kikuchi; Y. Achiba; I. Ikemoto

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 420 KB
• Volume: 19
• Category: Article
• ISSN: 0921-5107
• DOI: 10.1016/0921-5107(93)90179-q

✦ Synopsis

The magnetic and electronic properties of oxygen-free, single-crystal and cesium compounds of Coo have been investigated. In non-doped crystals, a remarkable effect of oxygen absorption has been observed. The resistivity increases by a factor of 104 on absorption of oxygen, while the susceptibility shows a paramagnetic increase which obeys the Curie law. More than 8% 02 per C6o molecule is absorbed reversibly at ambient pressure and temperature, and is considered to be in the form of an 02 molecule but in a little ionized state. For the oxygenfree single crystal, the impurity level energy is obtained from the temperature dependence of the resistivity as 0.26 and 0.15 eV for T> T¢ and T< To, respectively, Tc being the rotational disorder transition temperature. In CsxC60 (x=0-4.5), the systematic study of susceptibility, electron spin resonance and X-ray diffraction reveals the existence of the CslCoo phase, in addition to x = 4 and 6 phases. CslCoo, which has the NaC1, is a metallic phase. Cs4Coo is an insulator with a paramagnetic moment of 0.7/zB per Coo molecule and a small antiferromagnetic interaction (0 = -5 K). The appearance of the magnetic moment in the multivalent Coo compound suggests that electrons in the conduction band are localized owing to the correlation effect.