SiC granule films were fabricated onto porous glass substrate by RF-magnetron sputtering. Photoluminescence （PL） measurements show that there are light emissions at three different wavelengths. Ultraviolet emission ...SiC granule films were fabricated onto porous glass substrate by RF-magnetron sputtering. Photoluminescence （PL） measurements show that there are light emissions at three different wavelengths. Ultraviolet emission peaked at 360 nm originated from the band-band transmission of SiC nanoparticles with relatively small size. The 370 nm light emission was due to the luminescence of the nano-skeletons of porous glass that was formed during the etching of the glass substrate. The blue emission at about 460 nm was associated with the recombination of the excited electron and O-deficient defects appeared at the interface between SiC nanoparticles and the porous glass. Furthermore, the optimal PL performance was obtained when SiC deposited time was I h and the glass substrate was etched for 20 min in the annealing sample （450 ℃）.展开更多
Perovskitelike manganese oxides La_(l-x)Na_(x)MnO_(z)(x=0.075,0.100,0.165,0.200)have been fabricated using sol-gel technique.Structure analysis,temperature programmed reduction(TPR)technique and magnetic measurement h...Perovskitelike manganese oxides La_(l-x)Na_(x)MnO_(z)(x=0.075,0.100,0.165,0.200)have been fabricated using sol-gel technique.Structure analysis,temperature programmed reduction(TPR)technique and magnetic measurement have been used to study the effect of Na ion substituted amount on Mn-O distance,the oxygen content,and the magnetocaloric properties of these materials.Results show there is no clear correlation between the substituted amount and mean Mn valence,but a close relationship is observed between Tc and the bond distance of Mn-O.These materials have quite large magnetic entropy changes upon an application of a low magnetic field and can be utilized as more suitable candidates for magnetic refrigerants with wide temperature span.展开更多
基金National Science Foundation of China (10774037)Natural Science Foundation of Hebei Province (E2007000280)Foundation of Hebei Educational Committee (2006123)
文摘SiC granule films were fabricated onto porous glass substrate by RF-magnetron sputtering. Photoluminescence （PL） measurements show that there are light emissions at three different wavelengths. Ultraviolet emission peaked at 360 nm originated from the band-band transmission of SiC nanoparticles with relatively small size. The 370 nm light emission was due to the luminescence of the nano-skeletons of porous glass that was formed during the etching of the glass substrate. The blue emission at about 460 nm was associated with the recombination of the excited electron and O-deficient defects appeared at the interface between SiC nanoparticles and the porous glass. Furthermore, the optimal PL performance was obtained when SiC deposited time was I h and the glass substrate was etched for 20 min in the annealing sample （450 ℃）.
基金Supported by the National Natural Science Foundation of China under Grate No.59676021 and 85-06 Nano-materials Science。
文摘Perovskitelike manganese oxides La_(l-x)Na_(x)MnO_(z)(x=0.075,0.100,0.165,0.200)have been fabricated using sol-gel technique.Structure analysis,temperature programmed reduction(TPR)technique and magnetic measurement have been used to study the effect of Na ion substituted amount on Mn-O distance,the oxygen content,and the magnetocaloric properties of these materials.Results show there is no clear correlation between the substituted amount and mean Mn valence,but a close relationship is observed between Tc and the bond distance of Mn-O.These materials have quite large magnetic entropy changes upon an application of a low magnetic field and can be utilized as more suitable candidates for magnetic refrigerants with wide temperature span.
