EPR Study of the Two-Dimensional Quantum System Cu(en)(H₂O)₂SO₄

The angular dependence of electron paramagnetic resonance spectra of Cu(en)(H₂O)₂SO₄ single crystals was studied in the X-band frequency range at temperatures 4 and 300 K. Analysis of the linewidth at 300 K revealed nice agreement with the angular variation of the g-factor. This coincidence is the manifestation of the symmetric and antisymmetric exchange coupling, as main broadening mechanisms in Cu(en)(H₂O)₂SO₄ at high temperatures. The radical change of the angular dependence of the linewidth observed at 4 K can be ascribed to dipolar coupling.