Stable discharging of pure nitrogen can be maintained even at atmospheric pressure when alternative pulsed voltage is applied between two parallel plate electrodes. We evaluated the nitrogen plasma generated by an alternative pulsed voltage system. The excited nitrogen species in a pure nitrogen plasma was evaluated using optical emission spectroscopy. In the discharging space, the largest peak detected corresponded to the N2 second positive system. Additionally, the emission peaks from the excited nitrogen atom were detected at a pressure of as high as 45Torr. In the downstream space, we detected emission peaks from the N2 Herman’s infrared system as well as the N2 second positive system. The N2 (AΣu+3) state is considered to be the origin of the N2 Herman’s infrared system. The emission intensities from the N2 second positive system and the N2 Herman’s infrared system increase with increasing nitrogen gas pressure, whereas the emission intensity from the N2+ first negative system decreases.

No abstract

We have investigated the surface magnetism of 5 at% Co-doped rutile TiO 2 (110) using magnetization-induced optical second harmonic generation (MSHG) in the longitudinal Kerr configuration with the incident beam angle of 4• . MSHG is observed at both 2 ω = 2.33 eV and 2 ω = 4.20 eV. MSH intensity showed a hysteresis as a function of the external magnetic field for the second harmonic photon energy of 2 ω = 4.20 eV at which the absorption length limits the MSHG origin to the surface layer of 10 nm due to the TiO 2 bulk. Since 5 at% Co: TiO 2 (110) is judged to have no metallic Co near the top surface by XPS, the hysteresis is attributed to a carrier-induced ferromagnetism at the surface of this material.

No abstract

No abstract