A series of Y2.985Al5–xGaxO12:0.015Ce(YAGG:Ce,x=0,1,2,3,4,5)transparent ceramics were prepared via a solid-state reaction method.Two-step sintering technique was proved to be an effective approach to prepare function...A series of Y2.985Al5–xGaxO12:0.015Ce(YAGG:Ce,x=0,1,2,3,4,5)transparent ceramics were prepared via a solid-state reaction method.Two-step sintering technique was proved to be an effective approach to prepare functional ceramics with high Ga concentration,and Y3Ga5O12(YGG)transparent ceramic was successfully prepared for the first time.According to the variation of Al/Ga ratio,regulation of band structure and luminescence properties of YAGG:Ce transparent ceramics were effectively investigated.When Ga substitutes Al sites,the tetrahedral site is more favorable compared to the octahedral site for Ga to occupy according to the first-principle calculation.A continuous blue shift of the emission from 565 to 515 nm was achieved as Ga was gradually introduced into Y3Al5O12:Ce matrix.High quality green light was obtained by coupling the YAGG:Ce ceramics with commercial blue InGaN chips.Transparent luminescence ceramics accomplished in this work can be quite prospective for high power LED application.展开更多
以采用水热法制备的BaTiO_3粉体作为原料,利用普通烧结法和两步烧结法制备出晶粒尺寸为0.25~10.15μm的BaTiO_3陶瓷,研究了晶粒尺寸效应对BaTiO_3陶瓷的介电、压电以及铁电性能的影响。结果表明:BaTiO_3陶瓷的四方相含量随着陶瓷晶粒尺...以采用水热法制备的BaTiO_3粉体作为原料,利用普通烧结法和两步烧结法制备出晶粒尺寸为0.25~10.15μm的BaTiO_3陶瓷,研究了晶粒尺寸效应对BaTiO_3陶瓷的介电、压电以及铁电性能的影响。结果表明:BaTiO_3陶瓷的四方相含量随着陶瓷晶粒尺寸的增大而增加;当晶粒尺寸在1μm以上时,室温相对介电常数(e￠)和压电系数(d33)随着晶粒尺寸的减小而增大,并在晶粒尺寸为1.12μm时分别达到最大值5628和279 p C/N,然后两者随着晶粒尺寸的进一步减小而迅速下降。BaTiO_3陶瓷的剩余极化强度Pr随晶粒尺寸的增大而提高,而矫顽场Ec却呈现出相反的趋势。晶粒尺寸对介电性能和压电性能的影响是由于90°电畴尺寸和晶界数量的变化。晶粒的晶体场和晶粒表面钉扎作用的变化影响了电畴,进而改变电滞回线。展开更多
基金Acknowledgements The authors would like to thank the National Science Foundation of China （60807036）, the Leading Foundation of Shanghai （08JC1417200）, and the Laboratory of Rare Earths Functional Materials of Shanghai （07dz22303） for supporting the research.
基金supported by the National Key R & D Program of China (2016YFC0101800)National Natural Science Foundation of China (51672286, U1832159, 51772185)Science and Technology Major Project of Ningbo Municipality (2017C110028)
文摘A series of Y2.985Al5–xGaxO12:0.015Ce(YAGG:Ce,x=0,1,2,3,4,5)transparent ceramics were prepared via a solid-state reaction method.Two-step sintering technique was proved to be an effective approach to prepare functional ceramics with high Ga concentration,and Y3Ga5O12(YGG)transparent ceramic was successfully prepared for the first time.According to the variation of Al/Ga ratio,regulation of band structure and luminescence properties of YAGG:Ce transparent ceramics were effectively investigated.When Ga substitutes Al sites,the tetrahedral site is more favorable compared to the octahedral site for Ga to occupy according to the first-principle calculation.A continuous blue shift of the emission from 565 to 515 nm was achieved as Ga was gradually introduced into Y3Al5O12:Ce matrix.High quality green light was obtained by coupling the YAGG:Ce ceramics with commercial blue InGaN chips.Transparent luminescence ceramics accomplished in this work can be quite prospective for high power LED application.
文摘以采用水热法制备的BaTiO_3粉体作为原料,利用普通烧结法和两步烧结法制备出晶粒尺寸为0.25~10.15μm的BaTiO_3陶瓷,研究了晶粒尺寸效应对BaTiO_3陶瓷的介电、压电以及铁电性能的影响。结果表明:BaTiO_3陶瓷的四方相含量随着陶瓷晶粒尺寸的增大而增加;当晶粒尺寸在1μm以上时,室温相对介电常数(e￠)和压电系数(d33)随着晶粒尺寸的减小而增大,并在晶粒尺寸为1.12μm时分别达到最大值5628和279 p C/N,然后两者随着晶粒尺寸的进一步减小而迅速下降。BaTiO_3陶瓷的剩余极化强度Pr随晶粒尺寸的增大而提高,而矫顽场Ec却呈现出相反的趋势。晶粒尺寸对介电性能和压电性能的影响是由于90°电畴尺寸和晶界数量的变化。晶粒的晶体场和晶粒表面钉扎作用的变化影响了电畴,进而改变电滞回线。
