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TT: Fachverband Tiefe Temperaturen
TT 25: Superconductivity: Supercurrent Diode Effect
TT 25.7: Vortrag
Mittwoch, 19. März 2025, 11:15–11:30, H32
Josephson diode fabricated by a focused He-Ion beam in a YBa2Cu3O7 thin film. — •Edward Goldobin, Alireza Jozani, Christoph Schmid, Reinhold Kleiner, and Dieter Koelle — Universität Tübingen, Germany
We report on the fabrication of a Josephson diode with high asymmetry and size ≈ 1 µ m2. The device is fabricated from YBa2Cu3O7 thin films by creating nano-patterns using a focused He-ion beam (He-FIB). He-FIB irradiation of different doses allows us to “write” both Josephson barriers as well as amorphous resistive walls (circuit boundaries) on a sub-micron scale [1]. We have fabricated sub-µ m Josephson junctions of in-line geometry that have rather skewed Ic(H) dependences. At the optimal value of the applied magnetic field H, the ratio of positive and negative critical current Ic reaches ≈ 7. Such a high asymmetry is key for achieving good figures of merit, e.g. a wide rectification window, large stopping forces and a high rectification efficiency [2]. The rectification of an ac current into an average dc voltage ⟨ V ⟩ was investigated experimentally by measuring rectification curves ⟨ V ⟩(Iac) at T=4.2 K. Average dc voltages as high as 212 µ V were achieved for the optimum value of the driving amplitude Iac. Further, the diode was loaded, which allowed us to measure the input and the output power and, therefore, experimentally demonstrate the efficiency, which reaches 80% in some regimes [3].
[1] B. Müller et al., Phys. Rev. Applied 11, 044082 (2019).
[2] E. Goldobin et al., Phys. Rev. E 94, 032203 (2016).
[3] C. Schmid, et al., arXiv: 2408.01521 (2024).
Keywords: Josephson diode; YBCO; He-FIB; ratchet