FINE STRUCTURE IN ELECTRON PARAMAGNETIC RESONANCE OF MN2+ IN ZINC SULFATE

The electron spin resonance of 0.01% Mn2+ in single crystals of ZnSO4 has been studied in order to investigate the crystal-field interaction, which may be representative of the single-ion anisotropy in MnSO4. The symmetry group for the zinc site, which the Mn2+ ions are assumed to occupy, is Ci. There are, in general, four inequivalent zinc sites which produce a spectrum of 320 possible lines at an arbitrary orientation. However, data have been taken with H0 in symmetry planes of the crystal so that pairs of inequivalent sites become equivalent. This results in some simplification of the spectrum and provides a method for accurate alignment of the crystal. The spectrum has been fitted to a low-symmetry spin Hamiltonian. Since crystal-field terms are large, perturbation theory could not be used, and the spin-Hamiltonian analysis of the spectrum was accomplished by computer programs that diagonalize the spin-Hamiltonian matrix. An isotropic g factor of 2.0017±0.0010 and spin-Hamiltonian parameters C20=(3.792±0.001)×10-2 cm-1, C21=(3.815±0.001)×10-2 cm-1, C22=(5.808±0.001)×10-2 cm-1 with lobe orientations λ21=152.6°and λ22=86.5°describe the room-temperature spectrum reasonably well. The inclusion of the C4q terms improves the fit. © 1969 The American Physical Society.