Preparation of BiFeO3 thin films by pulsed laser deposition method

BiFeO3 （BFO） thin films were prepared on Pt（111）/TiO2/SiO2/Si（100） substrates by the pulsed-laser deposition （PLD） technique at a low temperature of 450℃. The XRD results indicate that the BFO thin films are of perovskite structure with the presence of small amount of second phases. The oxygen pressures have great effect on the crystalline structures and dielectric properties of BFO thin films. The dielectric constant of the BFO thin films decreases with increasing oxygen pressures, achieving 186, 171 and 160 at the frequency of 104 Hz for the oxygen pressures of 0.666, 1.333 and 13.332 Pa, respectively. The BFO thin films prepared at the oxygen pressure of 0.666 Pa reveal a saturated hysteresis loop with the remanent polarization of 7.5 ℃/cm^2 and the coercive field of 176 kV/cm.     

Effect of （Ba＋Sr）/Ti ratio on dielectric and tunable properties of Ba0.6Sr0.4TiO3 thin film prepared by sol-gel method

Ba0.6Sr0.4TiO3 （BST） thin films were fabricated on Pt coated Si （100） substrates by sol-gel techniques with molar ratio of （Ba＋Sr） to Ti changing from 0.76 to 1.33. The effect of （Ba＋Sr）/Ti ratio deviating from the stoichiometry on microstructure, grain growth, dielectric and tunable properties of BST thin films were investigated. TiO2 and （Ba,Sr）RTiO4 were found as a second phase at the ratios of 0.76 and 1.33, respectively. The variation of the ratio reveals more significant effect on the grain size in B-site rich samples than that in A-site rich samples. The dissipation factor decreases rapidly from 0.1 to 0.01 at 1 MHz with decreasing （Ba＋Sr）/Ti ratio. The tunability increases with decreasing ratio from 1.33 to 1.05, and then decreases with decreasing ratio from 1.05 to 0.76. The film with （Ba＋Sr）/Ti ratio of 1.05 has a maximum tunability of 32% and a dissipation factor of 0.03 at 1 MHz.     

溶胶—凝胶法合成了PZT—TiNi复合膜

以醋酸铅、异丙醇锆和钛酸正丁酯为先驱物,利用溶胶－凝胶在ＴｉＮｉ形状记忆合金箔基片上成功合成了ＰＺＴ铁电陶瓷薄膜,并研究了ＰＺＴ薄膜的晶化过程,结果表明,所得ＰＺＴ薄膜属钙钛矿结构无裂纹,与ＴｉＮｉ合金基结合牢固。     

PZT—NiTi铁电—铁弹多层膜的制备及表征

用溶胶－凝胶法制备了ＰＺＴ压电薄膜,研制了Ａｕ／ＰＺＴ／ＰＴ／ＴｉＯ２／ＮｉＴｉ／Ｓｉ（１００）多层膜结构,用ＸＲＤ,ＡＦＭ,ＴＥＭ－ＥＤＸ和ＳＡＤ技术考察了薄膜的表面形貌,相结构演化,以及面的元素分布特性。结果表明：ＰＺＴ膜与ＮｉＴｉ合金膜的结合良好,稳定;ＰＴ层的引入,使无定型ＰＺＴ薄膜在５５０℃退火后,转变为钙钛矿结构,降低了晶化温度,并有效地抑制焦碌石相的形成;ＮｉＴｉ薄膜结晶良好;ＴｉＯ     

Bi(GaxFe1-x)O3-PbTiO3高温压电陶瓷的结构和介电性能

采用传统固相反应法制备了0.4Bi(GaxFe1-x)O3-0.6PbTiOa (BGF-PT) (x=0.05,0.25,0.40,质量分数)陶瓷.BGF-PT呈四方相钙钛矿结构,四方畸变度c/a比约为1.09.当x(Ga) =25％时,BGF-PT陶瓷的晶粒分布均匀,Fe元素在局部区域无明显富集,该组分陶瓷在室温下具有最优的介电性能,居里温度为572℃.BGF-PT陶瓷在较低温度和高温下的载流子分别为电子和氧空位.Ga元素的引入抑制了电子电导和氧空位离子电导,降低了BGF-PT陶瓷的交流电导率.