# Critical current density in the superconducting ceramic $\rm La_{1.8}Sr_{0.2}CuO_4$ in S-c-N point contacts

## TL;DR

This study measures the critical current density in La_{1.8}Sr_{0.2}CuO_4 superconducting ceramics using point contact techniques, revealing values comparable to pair-breaking currents predicted by standard superconductivity theory.

## Contribution

It provides the first direct measurement of critical current density in nanoscale regions of La_{1.8}Sr_{0.2}CuO_4 ceramics, demonstrating their high current-carrying capacity.

## Key findings

- Critical current density reaches 10^8 A/cm^2 in superconducting regions.
- Measured values are comparable to theoretical pair-breaking current densities.
- Point contact measurements effectively probe individual crystallite properties.

## Abstract

Measurement of the current-voltage characteristics of point contacts makes it possible to study the properties of individual crystallites in a superconducting ceramic. The critical current density in the superconducting regions of the ceramic $\rm La_{1.8}Sr_{0.2}CuO_4$, with a size of the order of several tens of angstroms, is found to attain values of $10^8\ A/cm^2$, which are of the same order of magnitude as the pair-breaking current density, as evaluated from the formulas of the standard theory of superconductivity.