Direct measurements of anticrossings of the electron-nuclear energy levels in LiYF4∶Ho3+ with submillimeter EPR spectroscopy

摘要: The electron paramagnetic resonance (EPR) spectra of impurity Ho3+ ions in monocrystals LiYF4∶Ho3+ (0.1 and 1%) with the natural abundance of6Li (7.42%) and7Li (92.58%) isotopes, sample7LiYF4∶Ho3+ (0.1%) isotopically pure in7Li were taken at temperature 4.2 K frequency range 165–285 GHz. Resonance transitions between crystal field sublevels (the ground non-Kramers doublet nearest excited singlet) the5I8 term detected. refined set parameters effective constant magnetic hyperfine interaction determined from detailed analysis recorded frequencies varied by 0.05 fine structure EPR lines intervals about 300 MHz observed sample can be interpreted as a result isotopic disorder Li sublattices. Direct information energy gaps anticrossing points electron-nuclear was obtained. These are induced that mixes singlet states random fields. Weak signals distorted single ion pair centers resolved. From comparison measured simulated spectra, estimates spectral dimer have been