Direct Observation of Quantized Magnetic Flux in a Superconducting Hollow Cylinder with an Electron Interferometer

Abstract

Quantized magnetic flux trapped in hollow superconducting lead cylinders of extremely small dimensions (0.6 \ensuremath{\mu} i.d., film thickness \ensuremath{\le}0.5 \ensuremath{\mu}, length 100 \ensuremath{\mu}) was observed in an electron interferometer. The flux was found to be quantized in integer multiples of $\frac{h}{2e}\ifmmode\pm\else\textpm\fi{}4%$. No influence of the size of the tube upon the fluxoid quantum has been observed.