Ag对CoPt/Ag纳米复合膜的结构与磁性的影响

采用直流磁控溅射的方法制备了一系列(CoPt/Ag)_n多层膜，然后在不同温度下 进行了退火处理，并对其结构和磁性做了初步的表征，研究了Ag的含量以及薄膜中每一单元 厚度与总厚度对退火后薄膜的结构以及磁性能的影响.结果表明，膜厚较薄时(大约20 nm)有 利于薄膜沿(001)取向生长，Ag的加入不但能够抑制CoPt晶粒的过分长大还可以诱导薄膜的( 001)取向，使退火后的薄膜在垂直于膜面方向上的矫顽力大大增强.对于特定组分为Co ₄₀Pt₄₃Ag₁₇的薄膜，经600℃退火后已经显示了明显的(001) 取向，垂直于膜面方向上的矫顽力为5.6×10⁵ A/m，饱和磁化强度为0.65T, 并 且磁滞回线具有很好的矩形度，剩磁比(s)为0.95. 关键词： 磁记录材料 磁性薄膜 CoPt/Ag纳米复合膜     

CoPt(FePt)-C纳米复合膜的结构与磁性

用磁过滤脉冲真空电弧沉积方法制备了CoPt(FePt) C纳米复合薄膜，并在不同温度下进行了退火处理，研究了薄膜中碳的含量以及退火温度对薄膜结构与磁性能的影响.制备态薄膜经过足够高的温度退火后，x射线衍射和磁力显微镜分析发现，在碳基质中生成了面心四方相的CoPt(FePt)纳米颗粒.对于特定组分为Co24Pt31C45和Fe43Pt35C22的薄膜，矫顽力以及颗粒尺寸都随退火温度的升高而增大，当退火温度为700℃时，Co24Pt31C45薄膜的矫顽力为21×105A/m，晶粒尺寸为17nm;当退火温度为650℃时，Fe43Pt35C22相应值分别为28×105A/m和105nm. 关键词： 磁记录材料 磁性薄膜 CoPt FePt纳米复合薄膜     

垂直取向FePt/Ag纳米颗粒薄膜的结构和磁性

用磁控溅射法在单晶MgO(100)基片上制备了［FePt 2 nm/Ag dnm］₁₀多层膜， 经真空热处理后，得到具有高矫顽力的垂直取向L1₀-FePt/Ag颗粒膜.x射线衍射结 果表明，在250 ℃的热基片上溅射，当Ag层厚度d=3—11 nm时，FePt颗粒具有很好的［001］取向，随着Ag层厚度的增加，FePt颗粒尺寸减小.［FePt 2 nm/Ag 9 nm］₁₀经过6 00 ℃真空热处理15 min后，颗粒大小仅约8 nm，垂直矫顽力达到692 kA/m.这种无磁耦合作用的颗粒膜，适合用作超高密度的垂直磁记录介质. 关键词： 磁控溅射 垂直磁记录 纳米颗粒膜 0-FePt/Ag')" href="#">L1₀-FePt/Ag     

Ag和Ti底层对[Fe/Pt]n多层膜有序化的影响

利用磁控溅射的方法，在热玻璃基片上制备了以Ag，Ti，Cu，Cr，Pt和Ta为底层的［Fe/Pt］_n多层膜，后经不同温度真空热处理，得到L1₀有序结构的FePt 薄膜（L1₀-FePt）.实验结果表明，以Ag和Ti为底层，通过采用基片加温，同时 利用［Fe/Pt］_n多层膜结构，可以促进FePt薄膜的有序化过程，使FePt-L1_０有序化温度从500℃降低到350℃.在较高的温度下退火，以Ag为底层对薄膜的磁性 能影响较小，而以Ti为底层在高于500℃退火后，矫顽力明显下降.在400℃退火20min后，以 Ag和Ti为底层的样品平行膜面的矫顽力分别达到597kA/m和645kA/m，剩磁比分别达到0.81和 0.94，为将来FePt-L1_０有序相合金薄膜用于未来超高密度磁记录介质打下基础. 关键词： ０-FePt薄膜')" href="#">L1_０-FePt薄膜 有序化温度 底层 多层膜结构     

磁控溅射方法制备垂直取向FePt/BN颗粒膜

用磁控溅射在热单晶MgO(100)基片上制备了［FePt/BN］多层膜，经真空热处理后，得到具有垂直取向L1₀-FePt/BN颗粒膜.X射线衍射结果和磁性测量的结果表明，［FePt(2nm)/BN(0.5nm)］₁₀和［FePt(1nm)/BN(0.25nm)］₂₀多层膜经700℃热处理1h后，均具有较好的(001)取向.［FePt(1nm)/BN(0.25nm)］₂₀垂直矫顽力达到522kA/m，剩磁比达到0.99，开关场分布S达到0.94，FePt晶粒平均尺寸约15—20nm，适合用于将来超高密度的垂直磁记录介质. 关键词： 磁控溅射 垂直磁记录 0-FePt/BN纳米颗粒膜')" href="#">L1₀-FePt/BN纳米颗粒膜     

氧化钒薄膜微观结构的研究

采用直流磁控反应溅射在Si(100)衬底上溅射得到(001)取向的V₂O₅薄膜.x射线衍射(XRD)、扫描电镜(SEM)和傅里叶变换红外光谱(FTIR)的结果表明，氧分压影响薄膜的成分和生长取向，在氧分压0.4Pa时溅射得到(001)取向的纳米V₂O₅薄膜，即沿c轴垂直衬底方向取向生长的薄膜.V₂O₅薄膜经过真空退火得到(001)取向的VO₂薄膜，晶体颗 关键词： 微观结构 氧化钒薄膜 择优取向 直流磁控溅射     

VO$lt;sub$gt;2$lt;/sub$gt;/AZO复合薄膜的制备及其光电特性研究

采用直流磁控溅射和后退火氧化的方法在掺铝氧化锌(AZO)导电玻璃上制备了二氧化钒(VO₂)薄膜,研究了不同的退火温度、退火时间对VO₂/AZO复合薄膜制备的影响,并对复合薄膜的结构、组分、光电特性进行了测试与分析. 结果表明,导电玻璃上的AZO没有改变VO₂的取向生长,但明显改变了VO₂薄膜的表面形貌特征. 与用相同工艺和条件在普通玻璃基底上制备的VO₂薄膜相比,VO₂/AZO复合薄膜的相变温度降低约25 ℃,热滞回线宽度收窄至6 ℃,相变前后可见光透过率均在50%以上,1500 nm处红外透过率约为55%和21%,电阻率变化达3 个数量级. 该复合薄膜表面平滑致密,制备工艺简单,性能稳定,可应用于新型光电器件. 关键词： 2')" href="#">VO₂ AZO 热致相变 光电特性     

真空退火对Ni80Fe20/Cu多层膜微结构的影响

用直流磁控溅射法在Si(001)衬底上制备了以Ta为缓冲层、含有15周期的Ni₈₀Fe₂₀（4nm)/Cu(6nm)多层膜.样品分别在150,250,350℃进行了真空退火处理.用低角和高角X射线衍射法研究了多层膜的微结构.结果表明,所有样品均有较好的[111] 取向,而且随退火温度或时间的增加,[111]取向程度变得更高.超晶格周期、平均面间距在退火后略有减小,表明多层膜结构在退火后变得更为致密.多层膜界面粗糙度随退火温度或时间的增加而增大,平均相关长度随退火温度或时间的增加而减小,分析认为这是由于Ni₈₀Fe₂₀/Cu界面存在严重的互扩散所导致的.模拟Ni₈₀Fe₂₀/Cu多层膜高角X射线衍射谱,发现在Ni₈₀Fe₂₀/Cu蜀面有非常厚的混合层存在,而且混合层厚度随退火温度或时间的增加而增大.模拟结果还表明,随退火温度或时间的增加,Ni₈₀Fe₂₀层面间距几乎保持不变,Cu层面间距则随退火温度的增加而略有减小. 关键词：     

高温退火处理下SiNx薄膜组成及键合结构变化

采用等离子增强化学气相沉积法, 以氨气和硅烷为反应气体, p型单晶硅为衬底, 低温下(200 ℃)制备了非化学计量比氮化硅(SiN_x)薄膜. 在N₂氛围中, 于500–1100 ℃范围内对薄膜进行热退火处理. 室温下分别使用Fourier变换红外吸收(FTIR)光谱技术和X射线光电子能谱(XPS)技术测量未退火以及退火处理后SiN_x薄膜的Si–N, Si–H, N–H键键合结构和Si 2p, N 1s电子结合能以及薄膜内N和Si原子含量比值R的变化. 详细讨论了不同温度退火处理下SiN_x薄膜的FTIR和XPS光谱演化同薄膜内Si, N, H原子间键合方式变化之间的关系. 通过分析FTIR和XPS光谱发现退火温度低于800 ℃时, SiN_x薄膜内Si–H和N–H键断裂后主要形成Si–N键; 当退火温度高于800 ℃时薄膜内Si–H和N–H键断裂利于N元素逸出和Si纳米粒子的形成; 当退火温度达到1100 ℃时N₂与SiN_x薄膜产生化学反应导致薄膜内N和Si原子含量比值R增加. 这些结果有助于控制高温下SiN_x薄膜可能产生的化学反应和优化SiN_x薄膜内的Si纳米粒子制备参数. 关键词： x薄膜')" href="#">SiN_x薄膜 Fourier变换红外吸收光谱 X射线光电子能谱 键合结构     

用于红外激光防护的高开关率VO2薄膜

采用反应离子束溅射和后退火处理技术在石英玻璃基底上制备了具有纳米粒子的二氧化钒(VO₂)薄膜. 该薄膜具有半导体-金属相变特性,在3 μm处的开关率达到76.6%。 热致相变实验结果给出了准确的最佳退火温度为465 ℃. 仿真、热致相变和光致相变实验都显示VO₂薄膜在红外波段具有很高的光学开关特性. 光电池防护实验结果显示VO₂薄膜将硅光电池的抗干扰能力提升了2.6倍, 证明了VO₂在激光防护中的适用性. 采用连续可调节系统研究得到VO₂在室温条件下的相变阈值功率密度为4.35 W/cm², 损伤阈值功率密度为404 W/cm²。 低相变阈值和高损伤阈值都进一步证明VO₂薄膜适用于激光防护系统。本实验制备的VO₂薄膜在光开关、光电存储器、智能窗等方面也具有广泛的应用价值.     

Structure and magnetic properties of CoPtCu:Ag nanocomposite films with (001) texture

Nanocomposite (001) textured CoPtCu:Ag films consisting of well separated L1₀ structure CoPtCu nanoparticles have been prepared using a CoPt/Cu/Ag multilayer precursor on SiO₂/Si(100) substrate by magnetron sputtering and subsequent vacuum thermal annealing. With a Cu concentration of 6–10% and Ag of 10–20% in atomic ratio, the films start ordering at an annealing temperature of 450 °C, which is roughly lower by 150 °C than that needed for most CoPt-based films especially with (001) texture. The perpendicular coercivities for the film are in the range from 5 kOe to 7 kOe after annealing at 500 °C in vacuum. The (001) texture for the film is partially due to the formation of an Ag underlayer after annealing, the decreasing of the ordering temperature is most-likely related to the formation of CoPtCu alloy nanoparticles in the film. PACS 75.30.Gw; 75.50.Kj; 75.70.Ak     

Microstructures and magnetic properties of CoPt-TiO2 nanocomposite films prepared by annealing CoPt/TiO2 multilayers

CoPt-TiO₂ nanocomposite films were synthesized by rapid thermal annealing of CoPt/TiO₂ multilayers. The effects of annealing temperature, annealing time, Ag addition and TiO₂ volume fraction on the microstructures and magnetic properties of the CoPt-TiO₂ nanocomposite films were studied. Results showed that the ordering degree of CoPt and coercivity of CoPt-TiO₂ nanocomposites increased with annealing temperature. Increasing annealing time and Ag addition were able to increase the ordering degree and coercivity of CoPt. However, complete L1₀-ordering of CoPt at 550 °C annealing was not realized by increasing annealing time up to 30 min and Ag addition up to 30 vol.%. Increasing TiO₂ volume fraction at 700 °C annealing did not lead to the change of ordering of CoPt. However, the grain structure of the films changed slightly when TiO₂ volume fraction was larger than 56%. The coercivity of the film decreased slightly with the addition of TiO₂.     

Low-temperature deposition of L10 FePt films for ultra-high density magnetic recording

A method based on strain-induced phase transformation was used to lower the ordering temperature of FePt films. The strain resulted from the lattice mismatch between the FePt film and the substrate or underlayer favored the ordering. The relationships between the lattice mismatch, the ordering of FePt film, and the corresponding magnetic anisotropic constant were investigated. A critical lattice mismatch near 6.33% was believed to be most suitable for improving the chemical ordering of the FePt films. CrX (X=Ru, Mo, W, Ti) alloys with (2 0 0) texture was used to control the easy axis and ordering temperature of FePt films on glass substrate. Large uniaxial anisotropy constant K_u?1×10⁷ erg/cm³, good magnetic squareness (∼1) and FePt(0 0 1) texture (rocking curve −5°) were obtained at the temperature T_s?250 °C when using CrRu underlayer. The diffusion from overlying layers of Ag and Cu and an inserted Ag pinning layer were effective in reducing the exchange decoupling and changing the magnetization reversal. The media noise was effectively reduced and the SNR was remarkably enhanced when a 2 nm Ag was inserted.     

Structure and magnetic properties of annealed metastable FeAg/Pt films

FeAg and FeAg/Pt films were prepared by dc magnetron sputtering at room temperature. The effects of Ag volume fraction in FeAg films and postannealing temperature and time on structure and magnetic properties of FeAg and FeAg/Pt films have been investigated. The results show that the as-deposited FeAg films are metastable. After annealing at 300°C, the phase separation of metastable FeAg films happened and the highest coercivity is obtained in Fe₅₀Ag₅₀/Pt film. With increasing annealing temperature, the ordering and the magnetic properties of the Fe₅₀Ag₅₀/Pt films were improved. When the Fe₅₀Ag₅₀/Pt films are annealed at 600°C for different annealing times, a long annealing time enhances the ordering of the metastable Fe₅₀Ag₅₀/Pt films and affects the orientation development. When the films are annealed for a long time, the grain size and the magnetic domain size also increase, which lead to an increase of correlation length due to the growth of FePt grains.     

Microstructure and magnetic properties of FePt:Ag nanocomposite films on SiO2/Si(1 0 0)

FePt:Ag nanocomposite films were prepared by pulsed filtered vacuum arc deposition system and subsequent rapid thermal annealing on SiO₂/Si(1 0 0) substrates. The microstructure and magnetic properties were investigated. A strong dependence of coercivity and ordering of the face-central tetragonal structure on both Ag concentration and annealing temperature was observed. With Ag concentration of 22% in atomic ratio, the coercivity got to 6.0 kOe with a grain size of 6.7 nm when annealing temperature was 400 °C.     

Cu掺杂对FexPt1－x薄膜有序化的影响

利用磁控溅射制备了薄膜厚度为50nm的系列(Fe_xPt_1-x)_100-yCu_y(x=0.46—0.56,y=0,0.04,0.12) 样品.利用直流共溅射方法精确控制Fe和Pt的原子比.实验结果表明，当x>0.52时，样品中添加Cu不能促进FePt的有序化，但是对于FePt化学原子定比或富Pt的样品，添加Cu可以促进FePt有序化，而且随着Fe含量的减少，需要更多的Cu添加才能实现较低温度下FePt薄膜的有序化.实验结果表明，原子比(FeCu)/Pt达到1.1—1.2的范围时，即可实现较低温度的有序化. 关键词： 0-FePt有序相')" href="#">L1₀-FePt有序相 磁控溅射 有序度 Cu掺杂