Measuring Superconducting Stiffness and Coherence of Magnetic Materials with zero-applied field

TYPELow Temperature Seminar
Speaker:Mr. Amotz Peri
Affiliation:Technion
Organizer:Amit Keren
Date:04.08.2022
Time:11:30 - 12:30
Location:Lidow 620
Abstract:

Superconducting (SC) stiffness rho_s and coherence length xi are usually measured by applying a magnetic field and measuring its penetration depth into a material lambda and the upper critical field H_{c2}. However, in magnetic materials, e.g. iron-based superconductors, this could lead to erroneous results since the field couples to the magnetic moments. To overcome this problem, we applied the Stiffnessometer technique^{[1]} to measure both quantities in FeSeTe. In this technique, one applies rotor-free vector potential textbf{A} to a SC ring and measures with a SQUID the current density textbf{J} via its magnetic moment M of the SC. rho_s, and xi are determined from London’s equation textbf{J}=-rho_stextbf{A} and its range of validity. Our results will be compared with theoretical expectations and other techniques. 

 

[1]. I. Mangel, I. Kapon, N. Blau, K. Golubkov, N. Gavish, and A. Keren, Phys. Rev. B 102, 024502 (2020).