Polarization states of ZnO-based thin films probed by magnetic circular dichroism spectroscopy

ZnO films grown on a glass substrate through the magnetron sputtering were subjected to ion implantation of Ni+ and Ag+with different irradiation doses. The resulting ZnO: Ag and ZnO: Ni films were studied using optical and magneto-optical spectroscopy. Magnetic circular dichroism (MCD) spectra for the samples were analyzed along with MCD spectra for nickel and silver nanoparticles (NPs). The MCD data for Co-doped ZnO films was also considered. It has been found that MCD spectrum shape reflects different polarization states of charge carriers in the samples, as well as their magnetic behavior. In addition, it has been established that MCD spectroscopy can serve as a tool for the detection of Ni and Ag nanoparticles in matrices of ZnO: Ni and ZnO: Ag solid solutions. The general pattern of the MCD spectra observed for doped ZnO films in various magnetic and polarized states is expected to apply to other dilute oxides.