Physics at Virginia

Deaver featured in Physics Focus

Monday, January 4 2016

Deaver's seminal work with William Fairbank on magnetic flux quantization is featured in a Physics Focus: Landmarks article (Physics is an American Physical Society site that provides daily on-line news and commentary about papers from the APS journal collection).  This work provided evidence of electron paring in superconductors, as Fritz London had predicted that the smallest flux unit would be hc/e while the experiment yielded a value of hc/2e.
From the Focus: Landmarks article: 
"In the late 1950s, graduate student Bascom Deaver worked with William Fairbank at Stanford University in California to test this prediction. To make a superconducting ring, Deaver electroplated a thin layer of tin onto a copper wire. Deaver and Fairbank tested two different tin cylinders, each about one centimeter long, with an internal diameter of just over 10 micrometers.
Placed in a magnetic field and cooled in liquid helium to less than 3.7 degrees Kelvin, the tin became superconducting. The researchers then turned off the magnetic field. To measure any magnetic flux that remained trapped within the cylinder, they vibrated it back and forth at 100 hertz and measured the electrical signal generated in nearby coils of wire. They found that the flux through the cylinder increased in a stepwise fashion with increasing strength of the original applied field. The height of each step, however, was half the flux unit that London had predicted."
See the Landmarks article:

Tags: Bascom Deaver Condensed Matter Physics