28 August 2022 to 2 September 2022
Science and Technology Campus, University of Parma
Europe/Rome timezone
The Open Access Conference Proceedings is Now Available!

Phase transition from a magnetic-field-free stiffness meter and LEM viewpoints

O-31
1 Sept 2022, 11:20
20m
Science and Technology Campus, University of Parma

Science and Technology Campus, University of Parma

University of Parma, Italy
Oral Superconductivity Oral contributions

Speaker

Prof. Amit Keren (Technion Israel Institute of Technology)

Description

A new method to measure the superconducting stiffness tensor ${\bar \rho _s}$, without subjecting the sample to magnetic field, is applied to La$_{2-x}$Sr$_x$CuO$_4$ (LSCO) [1]. The method is based on the London equation $\mathbf{ J } = - \bar{{ \rho}}_\mathbf{s}\mathbf{ A}$, where $\mathbf{ J}$ is the current density and $\mathbf{ A}$ is the vector potential. Using rotor free $\mathbf{ A}$ and measuring $\mathbf{ J}$ via the magnetic moment of superconducting rings, we extract ${\bar \rho _s}$ at $T \to {T_c}$. The technique, named Stiffnessometer is sensitive to very small stiffness, which translates to penetration depth on the order of a few millimeters. We apply this method to two different LSCO rings: one with the current running only in the CuO$_2$ planes, and another where the current must cross planes. We find different transition temperatures for the two rings, namely, there is a temperature range with two-dimensional stiffness. The same method is also used to measure the coherence length $\xi_0$, by increasing $A$ to a point where linear response break. Finally, we compare our result with a LEM experiment performed on the same samples and discuss the advantage and disadvantage of each technique.

Primary authors

Prof. Amit Keren (Technion Israel Institute of Technology) Dr Itzik Kapon (Technion-Israel Institute of Technology) Mr Itay Mangel (Technion-Israel Institute of Technology) Prof. Nir Gavish (Technion-Israel Institute of Technology)

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