Magnetic, Thermal and Luminescence Properties in Room-Temperature Nanosecond Electron-Irradiated Nanopowders of Silicon and Cerium Oxides.

By means of pulsed electron beam evaporation in vacuum of targets non-magnetic, in bulk state, SiO₂ and CeO₂ oxides, magnetic nanopowders (NPs) with a high specific surface were produced. The NPs were subsequently irradiated in air by electrons with energy of 700 keV, using a URT-1 accelerator for 15 and 30 minutes. The magnetic, thermal, and pulsed cathodeluminescence (PCL) characteristics of NPs were measured before and after irradiation. It was established that the electron irradiation non-monotonically changes the magnetization of the pristine samples. To the contrary, a clear correlation between the intensity of PCL and the irradiation doses is found in the oxides. There was a decrease in the intensity of PCL after irradiation. Luminescent and thermal properties reflect the transformation of structural defects in NPs more strongly after the exposure to a pulsed electron beam in comparison with corresponding changes of the NPs magnetic response. [ABSTRACT FROM AUTHOR]