Superconductivity Shock: Iron Displays Quantum Characteristics Due to Vanadium Junction
An extraordinary event has been recorded where an electric current passing through a junction of vanadium and iron generates surprisingly loud static. This noise, significantly more intense than expected, reveals iron acting like a superconductor despite its inherent nature as a ferromagnet. A study published in Nature Communications validates long-held beliefs regarding the ability of superconductivity to transcend barriers and evoke quantum behavior in unexpected materials.
Researchers assessed electrical variations, referred to as shot noise, in devices comprised of vanadium situated apart from iron by a thin layer of magnesium oxide. The noise pattern disclosed electrons traversing in large, synchronized clusters inside the iron, mirroring the behavior typically observed when two superconductors establish a Josephson junction.
Josephson junctions function as essential components for quantum computers. Traditionally, they require two superconductors placed opposite each other across a barrier, synchronizing electron pairs despite their distance. The detection of junction-like activity with a single superconductor could greatly streamline quantum hardware designs, as highlighted by advancements acknowledged in the 2025 Nobel Prize in Physics.
Ferromagnetism Intersects with Superconductivity
Normally, iron should not show superconductivity. As a ferromagnet, it aligns electron spins in the same direction, while superconductors depend on electron pairs with counteracting spins, typically resulting in mutual cancellation. Astonishingly, vanadium succeeds in prompting iron to create same-spin electron pairs, establishing an unusual superconducting state alongside its magnetism. Researchers propose that spin-orbit coupling at the magnesium oxide midpoint may account for this atypical pairing.
Igor Žutić, SUNY Distinguished Professor at the University at Buffalo, elucidates this phenomenon with a metaphor: “A standard Josephson junction with two superconductors resembles two military battalions marching in unison on opposite banks of a river. In our experiment, there was merely one battalion — yet it’s as if its marching compelled citizens on the opposite side to form a militia and commence marching to the beat of an alternative drum.”
The researchers discerned this by examining shot noise, an unavoidable electrical jitter caused by electrons arriving in bursts instead of smoothly. In typical metals, electrons primarily arrive individually, whereas in superconductors, they travel in pairs. The noise detected in these iron junctions signifies coordinated group movement indicative of superconducting synchronization. The substantial intensity of this noise implies strong superconducting behavior triggered in the iron layer.
Clearing the Path for Quantum Hardware
The association between same-spin electron pairing and topological superconductivity could protect quantum information from environmental disruptions. Conventional quantum computers frequently lose data when electron spins are affected by external magnetic fields or thermal fluctuations. Topological strategies aim to encode information into knot-like configurations that are resistant to such disruptions.
Whether these iron junctions attain full topological protection remains uncertain. The team is still theorizing how the same-spin pairs became resilient enough to replicate Josephson junction behavior. However, the encouraging factor is the commercial availability of the involved materials. Iron and magnesium oxide are already in use in mainstream technologies like magnetic hard drives and random-access memory.
This international research collaboration features contributions from the Autonomous University of Madrid, where experiments were conducted in Farkhad Aliev’s laboratory, alongside teams from Comillas Pontifical University, the University of Lorraine, Babeș-Bolyai University, and the Eastern Institute for Advanced Study, with financial support from the U.S. Department of Energy’s Office of Science Basic Energy Sciences.
Žutić highlights the practical ramifications: “We have introduced a superconducting angle to commercially viable devices.” The current challenge is understanding how iron maintains its induced superconducting state and whether analogous effects can be engineered into other material combinations.