Co:BaTiO3/Si(100)纳米复合薄膜制备、微结构及其紫外光电子能谱研究

采用脉冲激光气相沉积(PLD)方法,在Si(100)晶面上制备了Co:BaTiO₃纳米复合薄膜.采用X射线衍射(XRD)结合透射电镜(TEM)方法研究了两种厚度Co:BaTiO₃纳米复合薄膜的晶体结构,当薄膜厚度约为30 nm时,薄膜为单一择优取向;当薄膜厚度约为100nm时,薄膜呈多晶结构.原子力显微镜(AFM)分析表明,当膜厚为30nm时,薄膜呈现明显的方形晶粒.采用紫外光电子能谱(UPS)研究了Co的价态和Co:BaTiO₃纳米复合薄 关键词： 3')" href="#">BaTiO₃ 纳米复合薄膜 紫外光电子能谱     

Co:BaTiO3/Si(100)纳米复合薄膜制备、微结构及其紫外光电子能谱研究

采用脉冲激光气相沉积(PLD)方法，在Si(100)晶面上制备了Co:BaTiO₃纳米复合薄膜.采用X射线衍射(XRD)结合透射电镜(TEM)方法研究了两种厚度Co:BaTiO₃纳米复合薄膜的晶体结构，当薄膜厚度约为30 nm时，薄膜为单一择优取向；当薄膜厚度约为100nm时，薄膜呈多晶结构.原子力显微镜(AFM)分析表明，当膜厚为30nm时，薄膜呈现明显的方形晶粒.采用紫外光电子能谱(UPS)研究了Co的价态和Co:BaTiO₃纳米复合薄     

Co:BaTiO3纳米复合薄膜的制备及其结构

用脉冲激光沉积技术(PLD)在MgO(100)基底上生长了嵌埋Co纳米晶的BaTiO3复合薄膜. 分别利用x射线衍射(XRD)、原子力显微镜(AFM)以及拉曼光谱(Raman)对薄膜的微观结构、表面 形貌进行了表征. 结果表明该薄膜为c轴取向的四方晶体结构，薄膜表面均匀、致密、 具有原子尺度的光滑性，其均方根表面粗糙度(RMS)达到015nmCo以纳米晶形式嵌埋BaTi O3基体中，呈单分散性均匀分布，其粒径随激光脉冲数的增加而增大. Co：BaTiO3纳米 复合薄膜拉曼峰的强度随钴纳米晶粒径的增加明显减弱，但是峰的宽度逐渐增加. 关键词： Co：BaTiO3 纳米复合薄膜 脉冲激光沉积     

Fabrication and electrical characterisation of Zr-substituted BaTiO3 thin films

Thin films of zirconium-substituted barium titanate were deposited by chemical solution deposition on platinum-coated silicon substrates at a temperature of 700 °C. The films showed a polycrystalline perovskite structure. The grain size was found to decrease with increase of Zr substitution. The effect of Zr substitution on the dielectric constant and the leakage was studied. It was found that with increasing Zr content the phase transition becomes diffuse and relaxor-like. The dielectric constant was also found to decrease with increasing amounts of Zr after an initial increase. The hysteresis loops became thinner and the remanent polarisation was found to decrease. The leakage behaviour was explained by Schottky theory. The barrier heights of the different films were calculated and found to vary between 1.12 eV and 1.19 eV. PACS 68.55.-a; 81.20.Fw; 77.84.Dy     

Microstructure of Ag/BaTiO3 films grown on MgO(100) substrate under external electric field

By applying an electric field parallel to the substrate surface, highly ordered Ag nanoparticles were homogeneously embedded in BaTiO₃ (BTO) films grown on a MgO(100) substrate. Transmission electron microscopy studies show that the BTO film is [100]-oriented. The general crystallographic orientation relationships between the composite film and MgO substrate are [100]_BTO//[100]_Ag//[100]_MgO and (010)_BTO//(010)_Ag//(010)_MgO. However, in films grown without an external electric field, Ag particles grow with random orientations and the BTO matrix is polycrystalline. Thus, electric fields are thought to meliorate the quality of the films by changing the growth orientation. In addition, the BTO matrix and Ag particles were found to be multiply twinned from studies on cross-sectional specimens. The contribution is discussed of Ag particles with ordered growth orientation and the large amount of BTO microtwins with higher dielectric constant to the improved optical properties of the as-prepared composite films.     

Structure and magnetization of (100) FeCr and FeV films deposited on Pd/Cu/Si(100)

(100) oriented FeCr and FeV films, 1000 Å thick, have been deposited on (100)Si using (100)Pd/Cu seed layers. Three compositions are made for each alloy, 75/25, 50/50 and 25/75, all show lattice spacings corresponding to a body-centered cubic structure. Magnetic measurement shows composition dependent magnetization: both FeCr and FeV with compositions of 75/25 and 50/50 are ferromagnetic, but not the ones with the composition of 25/75. In-plane magnetization along different crystalline axes shows the same crystalline anistropy as that of bulk Fe crystal for both 75/25 structures, with a higher magnetization along the [100] edge than the [110] one. For the 50/50 structures, the [100] edge shows a smaller magnetization at low fields than the [110] one, but exceeds the latter at higher field. The measured magnetizations are less than those from linearly diluted Fe lattices. The correlation between the structures and magnetic properties is discussed.     

Magnetic excitations in (SiO2)Co nano-composite films: Brillouin light scattering study

Behaviour of magnetic excitations in the Damon-Eshbach (DE) and backward volume (BV) geometries in nano-composite (SiO₂)_100−xCo_x (50% at<x<80% at) films has been studied by Brillouin light scattering (BLS). It has been shown that it is the structure of Stokes/anti-Stokes BLS lines in the DE geometry that allows reliable identification of dipole-exchange spin waves (SW) and numerical estimation of the value of the effective exchange constant A_eff of a super-ferromagnetic nano-granular sample (x=80% at).     

金属纳米团簇复合薄膜Au/BaTiO3与Fe/BaTiO3的PLD制备及其光吸收特征

用脉冲激光沉积技术制备了掺杂纳米金属颗粒Au或Fe的BaTiO3复合薄膜.用透射电子显微镜和x射线光电子能谱表征了金属颗粒的形态和化学态.330-800nm范围的吸收谱研究表明,掺Au颗粒的BaTiO3薄膜在580nm附近有一个明显的共振吸收峰,而掺Fe颗粒的BaTiO3薄膜没有这样的吸收峰.用Mie散射理论对结果进行了分析.