DIPOLAR FIELDS IN A LOW-DIMENSIONAL PARAMAGNET - CU(L-LEUCINE)2

A strong temperature variation in the gyromagnetic factor of the electron paramagnetic resonance line of bis(L-leucinato) copper (II) has been observed in single-crystal samples between 2 and 300 K. In order to characterize the magnetic properties and to evaluate the importance of short-range order effects we have also measured the magnetic susceptibility on powder samples. Thc data on the g-shift are interpreted as the combined effect of the dipole-dipole inter-action between copper ions, and the spin polarization induced by the applied magnetic field when the temperature is lowered. The layered distribution of the Cu ions in the crystal lattice makes this effect non-negligible and determines the quasi-two-dimensional behaviour of the shift.