DIELECTRIC INVESTIGATION ON CUO SINGLE-CRYSTALS PHASES TRANSITIONS

Two magnetic transitions have been identified in CuO by several magnet ic, thermodynamic and structural studies: at 230 K to an incommensurat e antiferromagnetic phase and at 212 K to a commensurate one. Anyway t he magnetic coordination has not been satisfactorily explained. In ord er to obtain further data on the nature of these phases, an investigat ion has been performed by means of dielectric measurements on single c rystals, in the audiofrequency range and at temperatures ranging betwe en 10 and 300 K. Two peaks are detected corresponding to the transitio n temperatures and anomalies in the a.f.m. phase at 150 and 90-110 K a re evidenced.