Lecturer: Amit Keren, Technion
Abstract:
The London equation states that in a superconductor the current density is proportional to the vector potential. The proportionality constant is called stiffness. We present a new method
for measuring the stiffness, without subjecting the sample to a magnetic field. By using rotor free vector potential and measuring the current density via the magnetic moment of superconducting rings, we extract the stiffness. The technique, named Stiffnessometer, is sensitive to very small stiffness, which translates to penetration depth on the order of the sample size. We apply this method to cuprate superconductors and thin films with surprising outcomes.