The Stiffnessometer - a magnetic-field-free superconducting stiffness meter and the nature of the phase transition in cuprates |
TYPE | Condensed Matter Seminar |
Speaker: | Itzik Kapon |
Affiliation: | Technion |
Date: | 26.06.2018 |
Time: | 14:30 |
Location: | Lidow Nathan Rosen (300) |
Abstract: | The Stiffnessometer - a magnetic-field-free superconducting stiffness meter and the nature of the phase transition in cuprates A new method to measure the superconducting stiffness tensor s, without subjecting the sample to magnetic field, is presented and applied to La1.875Sr0.125CuO4 (LSCO). The method is based on the London equation J=-sA, where J is the current density and A is the vector potential. Using rotor free A and measuring J via the magnetic moment of superconducting rings, we extract s. 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 CuO2 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 Stiffnessometer results are accompanied by Low Energy SR measurements on the same sample to determine the stiffness anisotropy at favorable temperatures.
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