Effect of ion doping on CuO magnetism

We have investigated the magnetism of 0.5 at. % Fe3+-doped CuO samples by M ossbauer spectroscopy and magnetization studies. The Curie-Weiss-type behav ior observed for low-field-magnetization measurements at temperatures highe r than 220 K is interpreted as an uncompensation of moments enhanced by the doping. The results are compared with 1.2 at. % Zn2+-doped CuO magnetizati on results and previous ones for samples doped with divalent ions. Trivalen t ion doping produces an increase in the susceptibility with a peak at T-N. The magnetic coupling of Fe2+ ions to the magnetic lattice is found to be about four times stronger than that of Fe3+. (C) 2000 American Institute of Physics. [S0021-8979(00)29708-9].