Benchtop High-MAS NMR for Paramagnetic Materials

We report a compact benchtop solid-state NMR platform that achieves 50 kHz magic-angle
spinning (MAS) in a 1.4 T permanent magnet with an 18 mm bore, enabling high-speed MAS
under extremely space-constrained conditions. The probe architecture leverages field–bore
orthogonality for convenient magic-angle alignment and is demonstrated with miniaturized
1.8 mm rotors (≈5 mm length) at stable high-speed operation. As a demanding test case,
we measure 7Li MAS NMR of the paramagnetic layered cathode oxide LiNi0.5Mn0.5O2,
where hyperfine interactions produce very large paramagnetic shifts spanning the several-
thousand-ppm regime. Overall, the results establish a path toward portable, cost-effective
high-MAS NMR in compact permanent-magnet geometries.