The world’s strongest iron-based superconducting magnet has been manufactured. Machine learning using Bayesian optimization was employed to improve the superconducting properties of potassium-doped barium iron arsenide (Ba,K)Fe2As2. Two large disk-shaped samples were fabricated using common industrial processing techniques under the best conditions deduced from data- and researcher-driven methods. After magnetizing the samples, they could retain a magnetic field of 2.83 T as a quasi-permanent magnet, around 2.7 times the previous record, with decay rates less than −0.1 ppm/h, crucial for MRI scanners. The two approaches produced divergent microstructures, opening the door to redefining what makes for a superior superconducting material.
- Akiyasu Yamamoto
- Shinnosuke Tokuta
- Mark D. Ainslie