Antiferro- to ferromagnetic transition in HfFe6Ge6-type solid solution YMn6Ge6-xGax (0.25

Photoluminescence (PL) and PL excitation spectra from Eu3+ implanted thermal growth SiO2 thin films have been investigated at room temperature. After annealing at 1000?C in N2, the red light emission from Eu ions doped SiO2 film, corresponding to the 5D0_7FJ transition of Eu3+, was observed. With increasing the annealing temperature (Ta) to 1200?C, a strong blue light emission band centered at around 450 nm appears. The conversion of Eu3+ to Eu2+ is discussed.