RESUMO
Crystalline nanowhiskers (NWs) composed of fullerene C60 and C70 molecules, i.e., alloy NWs, were synthesized by a liquid-liquid interfacial precipitation method. The nominal composition of C70 ranged from 0 to 40 mass%. The bending tests of the alloy NWs were performed inside a high-resolution transmission electron microscope, and the deformation behavior was observed in situ. The bending force acting on the NWs were measured simultaneously by an optical deflection method, and the Young's modulus was estimated from the resulting force-flexure curves. The average Young's modulus was found to increase to approximately 30 GPa as the C70 composition was increased to the solubility limit. In contrast, the Young's modulus decreased with increasing NW diameter caused by the addition of C70.
RESUMO
Superconductivity in alkali metal-doped fullerene nanowhiskers (C60NWs) was observed in K3.3C60NWs, Rb3.0C60NWs and Cs2.0Rb1.0C60NWs with transition temperatures at 17, 25 and 26 K, respectively. Almost full shielding volume fraction (~80%) was observed in K3.3C60NWs when subjected to thermal treatment at 200 °C for a duration of 24 h. In contrast, the shielding fraction of Rb3.0C60NWs and Cs2.0Rb1.0C60NWs were calculated to be 8% and 6%, respectively. Here we report on an extensive investigation of the superconducting properties of these AC60NWs (A = K3.3, Rb3.0 and Cs2.0Rb1.0). These properties are compared to the ones reported on the corresponding conventional (single-crystal or powder) K-doped fullerene. We also evaluated the critical current densities of these C60NWs using the Bean model under an applied magnetic field up to 50 kOe.