The properties of Co2+in zinc tungstate. I. The EPR spectrum and its interpretation

Measurements of electron paramagnetic resonance were made at 9.3 GHz and at liquid helium temperatures. The EPR spectrum was well represented by a spin hamiltonian of the form H=gx beta HxSx+gy beta HySy+gz beta HzSz+AxSxIx+AySyIy+AzSzIz+B(SxIz+SzIx) with gx=2.390+or-0.007, gy=3.41+or-0.02, gz=6.77+or-0.01, Ax=70+or-10 MHz, Ay=210+or-8 MHz, Az=900+or-5 MHz, mod B mod =30+or-5 MHz. The y axis coincides with the twofold b axis of the crystal and the x and z axes are the principal axes of the g tensor. These parameters reproduce the observed spectrum at all angles at which observations were made, within the experimental error of 5G. The value of B corresponds to a difference of approximately 1/4 degrees between the directions of the x axes of the g and A tensors. A theoretical analysis of the data is given and it is found that any Jahn-Teller effects are unimportant.