Field-Free Superconducting Diode Enabled by Geometric Asymmetry and Perpendicular Magnetization
Jiaxu Li, Zijian Zhang, Shiqi Wang, Yu He, Haochang Lyu, Qiusha Wang, Bowen Dong, Daoqian Zhu, Hisakazu Matsuki, Dapeng Zhu, Guang Yang, Weisheng Zhao
Published: 2025/6/21
Abstract
The superconducting diode effect (SDE)- manifested as directional, dissipationless supercurrents - is pivotal for realizing energy-efficient superconducting logic and memory technologies. Achieving high-efficiency SDE without external magnetic fields, however, remains a fundamental challenge. Here, we report a strongly enhanced, field-free SDE in Pt/Co/Nb heterostructures, enabled by the interplay of engineered geometric asymmetry and stray fields from a perpendicularly magnetized Co layer. This configuration promotes directional vortex entry and spatially selective pinning, yielding diode efficiencies that exceed all previously reported field-free values. Temperature- and field-dependent transport measurements, supported by micromagnetic simulations, reveal that the enhanced nonreciprocity stems from three cooperative mechanisms: asymmetric vortex entry, localized magnetic pinning, and Lorentz-force imbalance. These findings establish a scalable, CMOS-compatible platform for high-performance superconducting rectifiers, offering new opportunities for cryogenic spintronics and quantum electronics.