Techniques such as nuclear magnetic resonance require strong magnetic fields. Credit: Sakkmesterke/SPL Physicists have made an ultra-powerful magnet that fits in the palm of a hand1. Access Nature and 54 other Nature Portfolio journals Get Nature+, our best-value online-access subscription $32.99 / 30 days cancel any time Subscribe to this journal Receive 51 print issues and online access $199.00 per year only $3.90 per issue Rent or buy this article Prices vary by article type from$1.95 to$39.95 Prices may be subject to local taxes which are calculated during checkout doi: https://doi.org/10.1038/d41586-026-00851-y Gao, C. et al. Sci. Adv. 12, eadz5826 (2026).…