Superconductivity of C₆₀ Langmuir−Blodgett Films Doped with Potassium:  Low-Field Signal and Electron Spin Resonance Study

Abstract

Langmuir−Blodgett films of C60 were doped with potassium, and the doping was followed in situ by both microwave low-field signal (LFS) and electron spin resonance. The superconducting critical temperature was T c (onset) = 12.9 K for a nominal 14-layer film at optimum doping. The four-probe conductivity of an underdoped film as a function of temperature showed semiconducting behavior.

Langmuir−Blodgett Films of a Thermally Labile 1:1 Adduct of C60 Fullerene and 8-(9-Anthryl)-7-oxaoctanoic Acid

“…Considerable interest has been focused recently on how to form Langmuir−Blodgett (LB) films of C 60 . , One of us detected superconductivity by LFMA (low field microwave absorption) in a C 60 -LB multilayer film after K-doping; , another group has also found superconductivity in a LB multilayer of C 60 . These thin-film superconductors have critical temperatures lower than those observed in bulk samples or in thick evaporated films …”

Unimolecular Rectifiers and Proposed Unimolecular Amplifier

“…The Langmuir film is very rigid, that is, the slope of the pressure‐area isotherm (not shown) is large 28. However, the molecular areas are 70 Å2 at extrapolated zero pressure and 50 Å2 at the chosen LB film transfer pressure of 22 mN m −1 , whereas the molecular area of C 60 should be close to 100 Å 2 48,49. Therefore, it is thought that molecules 22 transferred onto Au on the upstroke are actually somewhat staggered, as shown in Figure 14, with the more hydrophilic dimethylamino group closer to the bottom Au electrode.…”

Synthesis of Heterocycles by Transition Metals-Catalyzed Cyclocarbonylation Reactions

“…Another stimulating area in new material science involves fullerene [C60] derivatives. Many fundamental properties of fullerene derivatives have been discovered and reported [97] and their metal derivates have evidenced attractive characteristics, such as superconductivity [98][99][100] or charge-transfer behaviour [101][102][103]. It is also well known that the structure of C60 is very rigid, hydrophobic, and exhibits peculiar properties totally different from those of rod-like self-assembling amphiphilic molecules.…”