Provided are a structure for reducing a
SQUID superconducting loop area, and a preparation method therefor, wherein a stacked structure is formed on a
silicon substrate, and precision
etching is performed on the stacked structure, so that a 3D nano-bridge junction is formed on a sloped surface of the stacked structure and stretches across an insulating layer, such that batch preparation of the structure for reducing a
SQUID superconducting loop area can be implemented, which facilitates large-scale application of
SQUID probes. The plane of the 3D nano-bridge junction is perpendicular to the plane on which a SQUID
superconducting loop is located, such that the width of the 3D nano-bridge junction no longer affects a SQUID effective loop area, so that the thickness of the 3D nano-bridge junction can be individually regulated in order to improve SQUID performance, which significantly weakens the inhibition effect of a
magnetic field on the superconducting characteristics of the 3D nano-bridge junction. In addition, the SQUID superconducting loop having a minimum
line width of 10nm can be prepared in combination with an
electron beam
lithography technique having higher precision, significantly reducing the SQUID superconducting loop area, improving spin sensitivity, and thereby achieving higher spatial resolution during scanning
magnetic imaging.