Nondestructive high-resolution solid-state NMR of rotating thin films at the magic-angle

Area of Science:

• Materials Science
• Analytical Chemistry
• Solid-State Physics

Background:

• Nuclear Magnetic Resonance (NMR) is a powerful technique for atomic-level structural analysis.
• Traditional NMR methods can be destructive or unsuitable for analyzing thin-film materials.
• There is a need for nondestructive NMR techniques to study thin films in their native state.

Purpose of the Study:

• To introduce a novel nondestructive magic-angle spinning (MAS) NMR approach for thin films.
• To demonstrate the feasibility of this method for analyzing thin-film composition and structure.
• To enable in situ and ex situ studies of thin-film devices.

Main Methods:

• A new scheme for nondestructive MAS NMR was developed.
• Disk-shaped samples (7 mm and 12 mm) were stably spun at 14.2 and 7 kHz.
• NMR signals were detected using an additional coil integrated with a conventional MAS system.
• 7Li MAS NMR experiments were performed on a 200 nm LiCoO2 thin film.

Main Results:

• Stable spinning of thin-film samples was achieved at relevant speeds.
• The method successfully characterized a 200 nm LiCoO2 thin film.
• Ex situ experiments demonstrated the ability to trace conformational changes upon annealing.
• The nondestructive nature of the technique was validated.

Conclusions:

• The developed nondestructive MAS NMR approach is effective for thin-film analysis.
• This method facilitates ex situ studies, tracking material changes over time.
• The technique holds promise for in situ MAS NMR studies of thin-film devices.