Field-free Josephson diode with controllable efficiency using magnetic tunnel barrier
Abstract
Josephson diodes (JDs) offer a promising route towards realizing dissipation-less rectification at low temperatures. To be practically viable, a JD must operate at zero magnetic fields, exhibit high operating frequencies and efficiency, and possess tunability and scalability. In this study, we propose and experimentally demonstrate a straightforward mechanism that encompasses all these crucial features. Our approach involves utilizing an asymmetric Josephson junction with a magnetic weak link to attain a diode effect in the switching current. We substantiate this concept experimentally through the fabrication of mesa-type sputter-deposited tri-layered ferromagnetic long NbN/GdN/NbN Josephson junctions (JJs) in cross geometry. A robust zero-field diode effect is observed with an efficiency boost of up to 40% achievable through modification of the micromagnetic structure of the barrier. Notably, these diodes maintain high efficiency across a wide temperature range, from the lowest temperatures up to at least 4.2K, and exhibit an operating frequency of nearly 28GHz.
Keywords
Cite
@article{arxiv.2312.04650,
title = {Field-free Josephson diode with controllable efficiency using magnetic tunnel barrier},
author = {Pramod K. Sharma and Sagnik Banerjee and Biswajit Dutta and Vansh Singhal and Pushpak Banerjee and Hridis K. Pal and Avradeep Pal},
journal= {arXiv preprint arXiv:2312.04650},
year = {2026}
}