High‐Temperature Superconducting SQUIDs: From Principles and Fabrication to Applications ‐ A Comprehensive Review

ABSTRACT Superconducting quantum interference devices (SQUIDs), as the most sensitive solid‐state magnetic sensors currently available, play a crucial role in both fundamental science and industrial applications. This review systematically examines the research progress in high‐temperature superconducting (HTS) SQUID magnetometers and gradiometers and their possible applications of SQUIDs. By detailing the working principles of DC and RF SQUIDs and reviewing advancements in critical system components—such as sensing elements, cryogenics, and readout electronics—this work lays a solid theoretical and structural foundation for ultra‐sensitive magnetic sensing. Furthermore, by describing the properties of various HTS Josephson junctions, their flexibility, and critical points, we aim at highlighting the uniqueness of certain features and the possibility of tuning a variety of physical processes in these junctions. Additionally, it comprehensively summarizes innovative applications in biomedical imaging, geophysical exploration, and industrial non‐destructive testing. The innovation of this review lies in constructing a developmental framework for HTS SQUID technology from a complete chain perspective of principles‐devices‐fabrication processes‐applications, providing systematic technical references for researchers in related fields, which has important guiding significance for promoting the practical application of quantum sensing technology.