Observation of nonlinearity and asymmetry in energies of EPR transitions of 160Gd3+ in La(C2H5SO4)3 · 9D2O at low magnetic fields

The energies of EPR transitions of ¹⁶⁰Gd³⁺ in La(C₂H₅SO₄₃ · 9D₂O at 77.2 K are observed to be nonlinear functions of field at low fields. The + $\text{3}\text{2}$, + $\text{1}\text{2}$ and ?$\text{3}\text{2}$, ?$\text{1}\text{2}$ transition energies converge asymmetrically below 10 G and differ by only ≈ MHz at the lowest fields employed.