Superconducting quantum interference phenomenon in Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ single crystals

TL;DR

This paper reports the fabrication and study of a dc-SQUID using intrinsic Josephson junctions in Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$, demonstrating quantum interference effects in high-temperature superconductor crystals.

Contribution

It introduces a novel in-plane loop layout and an in-situ endpoint detection method for precise control of junctions in the SQUID.

Findings

Observed clear periodic modulation of superconducting current with magnetic flux.

Provided unambiguous evidence of quantum interference in Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ crystals.

Demonstrated the feasibility of high-$T_c$ superconductor-based SQUIDs for quantum interference applications.

Abstract

The operational dc-SQUID based on intrinsic Josephson junctions in Bi$_2$Sr$_2$CaCu2O$_{8+\delta}$ high-$T_c$ superconductor is fabricated and studied. The novel in-plane loop layout and the developed in-situ endpoint detection method allowed an accurate control of the number of junctions in the SQUID. A clear periodic modulation of the superconducting current as a function of magnetic flux through the SQUID loop is observed. This is an unambiguous evidence for the quantum interference phenomenon in Bi$_2$Sr$_2$CaCu2O$_{8+\delta}$ single crystals.