Evidence for quasi-two-dimensional superconductivity in electron-doped Li-0.48(THF)(y)HfNCl - art. no. 020508

Dc-magnetization and NMR measurements were carried out on a layered superco nductor Li-0.48(THF)(y)HfNCl having T(c)similar to 26 K. For the magnetic f ield applied perpendicular to the basal plane (ab plane) above 10 kOe, we f ound a pronounced broadening of the superconducting transition in temperatu re dependence of magnetization and the substantial diamagnetic signals were observed as high as 2T(c), indicating the existence of superconducting flu ctuations. Analysis based on the anisotropic Ginzburg-Landau model reveals that the present system is a highly anisotropic superconductor. Li-7-NMR si gnals were observed around zero Knight shift, indicating that the local Fer mi-level density of states, N(E-F), at Li site is practically nothing and t he superconductivity is derived from the HfNCl layer. We have shown the una mbiguous evidence for the quasi-two-dimensional superconducting character i n this system.