Ultrahigh-frequency NMR of Tm3+ ions in single crystals of thulium ethylsulfate in high magnetic fields

Abstract

Resonant transitions predicted earlier between low-lying electron-nuclear sublevels of the Tm3+ ground state were observed at frequencies up to 700 MHz in a dielectric Van Vleck paramagnet—thulium ethylsulfate single crystal. It is shown that, due to the distortion of the 4f-electron shell of a rare-earth ion in an applied magnetic field, the parameters of electron-nuclear interaction become field-dependent.