Field cooling memory effect in Bi2212 and Bi2223 single crystals

TL;DR

This paper demonstrates a surprising memory effect in the Josephson vortex system of Bi2212 and Bi2223 superconductors, observed via microwave power absorption after field cooling, indicating persistent vortex configurations.

Contribution

It reveals a novel memory effect in highly anisotropic superconductors' Josephson vortices, despite their low viscosity, using microwave absorption measurements.

Findings

Memory effect observed in microwave power absorption signals.

Effect persists across a wide range of magnetic fields from 0.15T to 1.7T.

Memory effect is independent of the deviation from the cooling magnetic field.

Abstract

A memory effect in the Josephson vortex system created by magnetic field in the highly anisotropic superconductors Bi2212 and Bi2223 is demonstrated using microwave power absorption. This surprising effect appears despite a very low viscosity of Josephson vortices compared to Abrikosov vortices. The superconductor is field cooled in DC magnetic field H_{m} oriented parallel to the CuO planes through the critical temperature T_{c} down to 4K, with subsequent reduction of the field to zero and again above H_{m}. Large microwave power absorption signal is observed at a magnetic field just above the cooling field clearly indicating a memory effect. The dependence of the signal on deviation of magnetic field from H_{m} is the same for a wide range of H_{m} from 0.15T to 1.7T.