Electron paramagnetic resonance linewidth of CuCl2.2H2O near the Néel temperature

The electron paramagnetic resonance linewidth and the resonance field of the single absorption line of CuCl2.2H2O is studied immediately above the Néel temperature TN at 9600 MHz. It is found that the width of the line, which has a Lorentzian shape, increases slightly, down to 4.8 K. The linewidth dependence of the temperature below 4.8 K is found to be proportional to (T−TN)-0.58±0.07 for each of the magnetic axes. In the temperature region below T−TN≈ 0.02 TN the shape of the resonance line begins to deviate from the Lorentz type and becomes asymmetrical. The results are connected with short-range ordering and critical broadening above and below 4.8 K, respectively.