Novel method for accurate g measurements in electron-spin resonance

Abstract
In high‐accuracy work, electron‐spin‐resonance (ESR) g values are generally determined by calibrating against the accurately known proton nuclear magnetic resonance (NMR). For that method—based on leakage of microwave energy out of the ESR cavity—a convenient technique is presented to obtain accurate g values without needing conscientious precalibration procedures or cumbersome constructions. As main advantages, the method allows the easy monitoring of the positioning of the ESR and NMR samples while they are mounted as close as physically realizable at all time during their simultaneous resonances. Relative accuracies on g of ≊2×106 are easily achieved for ESR signals of peak‐to‐peak width ΔBpp≲0.3 G. The method has been applied to calibrate the g value of conduction electrons of small Li particles embedded in LiF—a frequently used g marker—resulting in gLiF: Li=2.002 293±0.000 002.