Schematic diagram showing the coils for the magnets. (Image Credit: Science Advances (2026). DOI: 10.1126/sciadv.adz5826.)
High-field magnets, especially those for Nuclear Magnetic Resonance (NMR) or particle accelerators, are massive, sometimes building-sized. Now, powerful magnets are shrinking. ETH Zurich engineers developed small magnets that can be carried in our hands and are comparable to the strongest ones we see today.
They created two types---one generates magnetic fields of 38 tesla and the other 42 tesla. These have a 63-millimeter outer diameter and a 3.1 mm bore. Currently, the strongest magnet is at the Florida-based National High Magnetic Field Laboratory. It runs on 20 MW and achieves 45.5 tesla.
Large resistive magnets that require megawatts of power and generate 42 tesla are composed of metal and wound around a cylinder. These also need complex cooling systems. With that in mind, the team put huge amounts of magnetic power in a small, compact space. To achieve this, they used high-temperature superconductors (HTS) tape that conducts significant amounts of energy without resistance once it reaches low temperatures.
They wrapped flat Rare Earth Barium Copper Oxide (REBCO) tape around disk-shaped pancake coils before placing them on top of each other. This allowed the magnetic field to be confined in a compact space while using less tape than standard designs. Joints that generate heat and waste power are normally used for linking magnets. The team avoided using that method by wrapping the tape in a complete loop, which also allowed electrical flow with minimal energy loss. Without tape insulation between turns, the coils were densely packed.
They experimented with both prototype magnets. Supplying them with over 1,000 A of current enabled them to generate 38 and 42 tesla. The ETH Zurich engineers are aiming to deploy this technology to NMR. Magnets like these could pave the way to tabletop systems instead of the massive machines used in facilities.
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