Synthesis and magnetic properties of zinc oxide:copper doped with magnetic impurities.

摘要

In this thesis we studied the magnetic properties of ZnO doped with magnetic impurities. Then the effects of adding the Copper to these samples were studied at different concentration of Cu.;The magnetization measurements were made for a series Zn0.9-x Fe0.1CuxO and Zn0.95-x Fe0.05Cu xO. At 4.2 K it is found that adding Cu concentration not only increases the magnetization but also results on the appearance of the hysteresis loop at Cu (0.01). Also, it is found from Arrott plot technique that all these samples have spontaneous magnetic moment at this temperature (4.2 K). Then, the molecular filed factor coefficients (gammam) and effective Fe-Fe exchange interactions (2J1/kB) at a specific value of applied magnetic field of 2 T also were calculated. We found that the coefficient (gammam) and the exchange interactions (2J1/k B) are positive meaning ferromagnetic exchange interaction present in these samples and these parameters increase when the concentration of Cu increases.;For Zn0.85-xCo.15CuxO samples from magnetization measurements it is found that increasing Cu concentration results on decreasing the magnetization at 4.26 K. Then, the presence of spontaneous magnetic moment for these samples was studied by Arrott plot technique. It is found that all samples don't have spontaneous magnetic moment. Finally, the molecular filed factor coefficients (gammam) and effective Co-Co exchange interactions (2J1/kB) at a specific value of applied magnetic field of 2 T also were calculated. We found that the coefficients (gammam) and the exchange interactions (2J1/kB) are negative meaning antiferromagnetic exchange interaction present in these samples and we found that the negative values of these parameters increase when the concentration of Cu increases.