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arXiv · 2610.16972

High-Efficiency Field-Free Superconducting Diodes in Mo$_2$N/FePt Bilayers

Juan S. Cruz·Emilio De Biasi·Juan C. Zapata·Yeonkyu Lee·Jeehoon Kim·Nestor Haberkorn
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Abstract

Near-ideal, field-free superconducting diode behavior is demonstrated in room-temperature-grown Mo$_2$N/FePt bilayers. The response is consistent with remanent FePt stripe domains producing polarity-dependent thresholds for flux entry and vortex motion. Micromagnetic simulations reveal a periodic stray-field modulation across the stripes and asymmetric field enhancement near their ends at the bridge edges. One current polarity remains nearly dissipationless up to a sizable fraction of the estimated depairing current, whereas the opposite polarity develops dissipation at much lower current, yielding diode efficiencies up to approximately 85% in the thinner bilayer. The nonreciprocity can be continuously tuned by the in-plane magnetic preparation angle and reversibly switched by reverse-field excursions through the hysteretic reversal of the FePt layer. These results support edge-controlled flux entry and vortex motion as a route to high-efficiency superconducting diodes.

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Juan S. Cruz, Emilio De Biasi, Juan C. Zapata, Yeonkyu Lee, Jeehoon Kim, Nestor Haberkorn. 2026-10-12. High-Efficiency Field-Free Superconducting Diodes in Mo$_2$N/FePt Bilayers. https://arxiv.org/abs/2610.16972

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