A Review of Tunable Wavelength Selectivity of Metamaterials in Near-Field and Far-Field Radiative Thermal Transport

Tian, Yanpei; Ghanekar, Alok; Ricci, Matt; Hyde, Mikhail; Gregory, Otto; Zheng, Yi

doi:10.3390/ma11050862

The SIS structure which consists of alternative thin lay- ers of superconductors and insulators on a bulk niobium has been proposed to shield niobium cavity surface from high magnetic field and hence increase the accelerating gradient. The study of the behavior of multilayer supercon- ductors in an external magnetic field is essential to opti- mize their SRF performance. In this work we report the de- velopment of a simple and efficient technique to measure penetration of magnetic field into bulk, thin film and mul- tilayer superconductors. Experimental setup contains a small superconducting solenoid which can produce a par- allel surface magnetic field up to 0.5 T and Hall probes to detect penetrated magnetic field across the superconduct- ing sample. This system was calibrated and used to study the effect of niobium sample thickness on the field of full magnetic flux penetration. We determined the optimum thickness of the niobium substrate to fabricate the multi- layer structure for the measurements in our setup. This technique was used to measure penetration fields of Nb 3 Sn thin films and Nb 3 Sn/Al 2 O 3 multilayers deposited on Al 2 O 3 wafers. The system was optimized to mitigate thermo- magnetic flux jumps at low temperatures.

More Like this