Enhanced Superconductivity Induced by the Hexagonal-Array-Cooling-Shrinkage Effect

Abstract

Improving the superconductivity of thin films, especially the critical current density (J C) and the critical field (H C), is crucial for the application of superconducting devices. Here, we apply a simple hybrid structure to enhance the superconductivity of Nb films induced by a hexagonal-array-cooling-shrinkage (HACS) effect, which is very sensitive to the temperature and magnetic field. The H C of the hybrid at 8.8 K is ∼32% more than that of a flat Nb film, while it is increased to ∼1000% at 8.97 K. In addition, the HACS effect to enhance superconductivity is more effective than that by uniform compression stress with the same value. The newly proposed approach can be used as self-protection to prevent superconducting devices from losing their superconductivity due to excessive current or magnetic fields.