J. Magn. Reson. http://doi.org/cc98 (2017)

The scientific history of nuclear magnetic resonance (NMR) has, in good part, been shaped by the ability to produce ever-stronger and yet exquisitely homogeneous magnetic fields. Higher fields typically mean improved sensitivity and resolution, but they also facilitate the emergence of new physical phenomena. Zhehong Gan and colleagues now describe a magnet design that enabled them to perform high-resolution NMR at 35.2 tesla — a field 50% stronger than that state-of-the-art equipment can produce in comparable quality.

Modern NMR systems are based on superconducting magnets, but at high field strength the materials involved have low current densities, limiting the achievable fields to around 23.5 T. Alternatively, resistive NMR magnets producing fields of up to 41 T are available, but their fields are usually too unstable for high-resolution NMR.

Gan et al., working at the National High Magnetic Field Laboratory in Florida, have now constructed a hybrid device in which resistive and superconducting coils are connected in series. With their novel design they produced fields exceeding 35 T with a stability within 0.2 ppm — enough to acquire high-resolution spectra of solid and dissolved samples.