Sign and magnitude of spin Hamiltonian parameters for Mn^2<b>+</b> impurities in calcite. A multi- and low-frequency EPR study

Abstract

L-, S-, and X-band powder EPR spectra and an L-band single-crystal spectrum of Mn2+ impurities in calcite were analysed by the fitting of full spectral traces to a theoretical model. This analysis gives as parameters the traditional spin Hamiltonian parameters reflecting the three-fold symmetry of the cation lattice site as well as parameters determining the band shape and width of the resonances. The three frequencies give a consistent description of the system. For this spin system it is shown that the relative sign of the axial zero-field splitting parameter Dand the hyperfine coupling constant A may be safely determined at the L-band.