The lossless current-carrying capacity of a superconductor is limited by its critical current density (J_c). A key to enhance J_c towards real-life applications is engineering defect structures to optimize the pinning landscape. For iron-based superconductors considered as candidate materials for high-field applications, high J_c values have been achieved by various techniques to introduce artificial pinning centres. Here we report extraordinary vortex pinning properties in CaKFe₄As₄ (CaK1144) arising from the inherent defect structure. Scanning transmission electron microscopy revealed the existence of nanoscale intergrowths of the CaFe₂As₂ phase, which is unique to CaK1144 formed as a line compound. The J_c properties in CaK1144 are found to be distinct from other iron-based superconductors characterized by a significant anisotropy with respect to the magnetic field orientation as well as a remarkable pinning mechanism significantly enhanced with increasing temperature. We propose a comprehensive explanation of the J_c properties based on the unique intergrowths acting as pinning centres.

超导体的无损载流能力受到其临界电流密度（J _c）的限制。提高J _c走向实际应用的关键是设计缺陷结构以优化钉扎环境。对于被认为是用于高场应用的候选材料的铁基超导体，通过引入人工钉扎中心的各种技术已经获得了很高的J _c值。在这里，我们报告了由于固有缺陷结构而在CaKFe ₄ As ₄（CaK1144）中产生的异常涡旋钉扎特性。扫描透射电子显微镜显示CaFe ₂ As的纳米级共生体的存在₂相，对于形成为线化合物的CaK1144而言是唯一的。发现CaK1144中的J _c特性与其他铁基超导体不同，这些超导体的特征是在磁场方向方面具有显着的各向异性以及随温度升高而显着增强的显着的钉扎机制。我们基于作为钉扎中心的独特共生物，提出了J _c性质的综合解释。