衬底温度对Fe-N薄膜结构、形貌及磁性能的影响

采用直流磁控溅射方法,以Ar和N2作为放电气体,在单晶Si(100)衬底上沉积了Fe-N薄膜.采用X射线衍射仪(XRD)、X射线光电子能谱分析仪(XPS)、原子力显微镜(AFM)和超导量子干涉仪(SQUIDS)对所制备的样品进行了结构、成分、形貌和磁性能分析,研究了衬底温度对薄膜的结构、形貌和磁性能的影响.结果表明:衬底温度对Fe-N薄膜的结构有重要的影响,通过控制衬底温度可以获得单相γ′-Fe4N化合物薄膜;γ′-Fe4N具有较高的饱和磁化强度,是非常有应用前景的磁记录介质及磁头功能材料.     

Effects of ZrO2 on the structure and magnetic properties of CoPt thin films

[CoPt 1.5 ml/ZrO2 xnm]10 multilayer films were deposited on glass substrates by magnetron sputtering and then annealed in vacuum at 600℃ for 30 min. Their structures and magnetic properties were investigated as a function of ZrO2 content. The results show that the grain size and coercivity first increase and then decrease with the increase in ZrO2 content. The maximum coercivity and grain size are obtained at 37 vol.% of ZrO2. The content of ZrO2 in the film plays an important role in the separation of CoPt grains and in the reduction of intergrain exchange interaction. On the basis of the studies of angular dependent coercivity, it is found that the magnetization reversal of CoPt films with （111 ） texture is different from either the domain wall motion or the S-W type of rotation mode.     

掺杂Bi促进L10-FePt有序转变的第一性原理研究

掺杂第三元素是促进FePt有序相变和降低有序转变温度的重要方法,元素Bi可大幅度降低有序转变温度,在低温下直接合成出高有序的FePt纳米粒子,但Bi促进FePt有序的机理和有序转变中的作用仍然是一个挑战。本文针对该问题,基于第一性原理密度泛函理论研究了Bi元素对FePt的晶格常数、形成能、差分电荷密度、饱和磁化强度和有序转变温度的影响。结果表明Bi原子取代Fe原子比取代Pt原子的替位形成能更低,Bi原子更容易取代Fe原子。Bi原子取代近邻位的替位形成能要比远邻位的替位形成能更低,Bi原子倾向于在FePt晶格内聚集。Fe原子是FePt体系磁性的主要来源,Bi原子对FePt的电子结构和磁性影响很小。掺杂Bi元素后FePt的有序转变温度明显降低,其中双掺杂情况FePt体系的有序转变温度最低为623.32K。空位机制在有序转变中起主导作用,Bi元素降低了FePt的空位形成能,提高体系中Fe原子和Pt原子的空位浓度并促进Fe原子和Pt原子的扩散和迁移,从而促进FePt有序相变。     

Effect of Ni doping on the microstructure and magnetic properties of FePt films

FePtNi films with different Ni contents were deposited on glass substrates by RF magnetron sputtering, and the Llx-FePtNi films were obtained after the as-deposited samples were subjected to vacuum annealing. The magnetic properties, structures, and orientations of the Llx-FePt films with Ni doping were studied. The results show that with increasing Ni content, the (001) peak position of the FePtNi films shifts to a higher angle in comparison with FePt. which suggests that there is partial Ni substitution in the Ll0 lattice. The perpendicular coercivity decreases from 661 to 142 kA/m and magnetization decreases from 512 to 433 kA/m with increasing Ni content. In comparison with FePt films, the FePtNi films can effectively reduce the Curie temperature, which makes FePtNi fdms promising media candidates in thermally assisted recording (TAR).     

Transparent conductive Sb-doped SnO2/Ag multilayer films fabricated by magnetron sputtering for flexible electronics

The effects of an embedded silver layer and substrate temperature on the electrical and optical properties of Sb-doped SnO₂ (ATO)/silver (Ag) layered composite structures on polyethylene naphthalate substrates have been investigated. The highest conductivity of ATO/Ag multilayer films was obtained with a carrier concentration of 1.5 × 10²² cm^?3 and a resistivity of 2.4 × 10^?5 Ω cm at the optimum Ag layer thickness and substrate temperature. The photopic averaged transmittance and Haacke figure of merit are 81.7%, and 21.7 × 10^?3 Ω^?1, respectively. In addition, a conduction mechanism is proposed to elucidate the mobility variation with increased Ag thickness. We also describe the influence of substrate temperature on the structural, electrical and optical properties of the ATO/Ag multilayer films, and propose a mechanism for the changes in electrical and optical properties at different substrate temperatures.     

退火温度对ZnTe薄膜结构和性能的影响

采用脉冲激光沉积法(PLD)在玻璃衬底上通过室温溅射和原位退火制备了ZnTe薄膜。通过X射线衍射(XRD)、原子力显微镜(AFM)、紫外-可见分光光度计和荧光分光光度计等研究了退火温度对薄膜结构和性能的影响。结果表明:薄膜具有明显的<110>择优生长特征。随着退火温度的升高,薄膜结晶质量逐渐提高,晶粒长大,透过率增加;但过高的退火温度降低了晶体的结晶质量和透过率。当退火温度为280℃时,ZnTe薄膜具有最好的结晶质量,平均透过率达到90%左右。     

Effect of annealing temperature on structure and electrochemical properties of LiCoO2 cathode thin films

LiCoO2 thin films, which can be used as a cathode material in microbatteries, were deposited using radio frequency (r.f.) magnetron sputtering system from a LiCoO2 target and in an O2+Ar atmosphere.The films were characterized by various methods such as XRD, SEM and AFM.The LiCoO2 films were annealed in air at 300, 500, 700 and 800 ℃ respectively.The effect of the annealing temperature on the structure, the surface morphology and the electrochemical properties of the films were investigated.The LiCoO2 thin film deposited at room temperature is amorphous and has smaller grain size.With increasing of annealing temperature, the crystallinity of the films is promoted.When the annealing temperature increases to 700 ℃, the films have a perfect crystalline LiCoO2 phase.The LiCoO2 thin film without annealing has no discharge plateau and small discharge capacity (about 27 μAh·cm-2μm).The discharge capacity increases with the increasing of annealing temperature and reaches 47 μAh·cm-2μm for the film annealed with 700 ℃, which also shows the typical discharge plateau of 3.9 V.The cycle performance of LiCoO2 thin films of as grown and annealed at different temperatures were studied.In the case of the film without thermal treatment, the capacity fading is much faster than that of the film annealed at different temperature, showing about 40% capacity loss only after 25 cycles.However, in the case of the film annealed at 700 ℃, the capacity reaches to steady state gradually and maintained constantly with cycling.After 25 times cycling, the discharge capacity of the film annealed at 700 ℃ decreases to about 36.9 μAh·cm-2·μm, only 0.8% capacity loss per cycle.     

Effect of Cu additive on the structure and magnetic properties of (CoPt)1-xCux films

CoPt thin films with various Cu contents varying from 0 vol.% to 21.5 vol.% were deposited on glass substrates by magnetron sputtering. The effects of Cu additive on the structural and magnetic properties and the ordering temperature of CoPt films were investigated in detail. The results show that the Cu in CoPt films plays an important role in promoting the ordering parameter S and reducing the ordering tempera-ture of CoPt films. A nearly perfect (001) texture was obtained in a CoPt film doped with 15.3 vol.% Cu. Besides, the preferred orientation of the CoPt film can be changed by annealing temperature. The perpendicular growth of the CoPt film is favored at a high annealing tempera-ture.     

Exchange biasing in SFMO/SFWO double perovskite multilayer thin films

In the present study, we have studied the exchange bias interaction in ferromagnetic Sr₂FeMoO₆ (SFMO)/antiferromagnetic Sr₂FeWO₆ (SFWO) multilayer thin films deposited on single crystal LaAlO₃ substrates using KrF pulsed laser deposition technique. XRD pattern revealed that SFMO, SFWO and their multilayer thin films were highly oriented along the c-axis. The microstructure studied by atomic force microscopy was found to be uniform, fine, dense and homogenous in nature. The observed magnetization-temperature curves showed Neel temperature T_N ∼ 37 K for SFWO and Curie temperature T_C > 320 K for SFMO thin films. For multilayer, the field cooled magnetization-field curve was shifted horizontally and the direction of the horizontal shift is opposite to that of H_FC, indicating an exchange bias effect. Exchange bias field H_E was found to decrease with increase in temperature and approached to zero at blocking temperature.     

Antimicrobial properties of diamond-like carbon-silver-platinum nanocomposite thin films

Silver and platinum were incorporated within diamond-like carbon (DLC) thin films using a multicomponent target pulsed laser deposition process. Transmission electron microscopy of the DLC-silver and DLC-platinum composite films reveals that these films self-assemble into particulate nanocomposite structures that possess a high fraction of sp ³-hybridized carbon atoms. Nanoindentation testing of DLC-silver nanocomposite films demonstrates that these films possess hardness and Young’s modulus values of approximately 35 and 350 GPa, respectively. DLC-silver-platinum films demonstrated exceptional antimicrobial properties against Staphylococcus and Pseudomonas aeruginosa bacteria. This paper was presented at the International Symposium on Manufacturing, Properties, and Applications of Nanocrystalline Materials sponsored by the ASM International Nanotechnology Task Force and TMS Powder Materials Committee on October 18–20, 2004 in Columbus, OH.     

磁控溅射沉积W-Ti薄膜的结构与性能

采用复合靶磁控共溅射方法在p型(100)单晶硅衬底上制备了不同Ti含量的W-Ti薄膜,并与纯W和纯Ti薄膜作对比。采用XRD、SEM、AFM、显微硬度计和四探针电阻仪对薄膜的结构、成分及性能进行分析表征。结果表明,W-Ti薄膜呈细晶粒多晶结构,Ti含量较低时,W-Ti薄膜呈体心立方相结构,存在W基W(Ti)固溶体。Ti含量较高时,还出现hcp富Ti相。W-Ti薄膜的显微硬度随Ti含量的增加先增后减,而电阻率则随Ti含量的增加而增大。W-Ti薄膜显微硬度均高于纯Ti薄膜,电阻率则高于纯W而低于纯Ti薄膜。     

Microstructure and magnetic properties of NiZn ferrite thin films prepared by sol-gel method

Ti^4＋ substitution for Fe^3＋ in Ni0.5Zn0.5Fe2O4 （NZF） ferrite thin films were realized by sol-gel method and annealing at 600℃for 30 min in the air. Crystal structure and lattice constant determination was performed by X-ray diffractometer （XRD）. Surface microstructure was observed by scanning electron microscope （SEM） and atomic force microscope （AFM）, and the magnetic properties were measured by vibrating sample magnetometer （VSM）. XRD analyses of the samples show that Ni0.5＋xZn0.5TixFe2-2xO4 （NZTF） films with x varing from 0 to 0.15 in steps of 0.05 are composed of single phase with spinel structure. And the lattice parameter, particle size and the diffraction intensity of the films increase with substitution of Ti as the result of the larger radius ions entering the lattice. SEM and AFM show homogeneous grain size of each sample, but there is a few differences in grain size with different Ti-substitution contents. As the nonmagnetic Ti^4＋ substitutes Fe^3＋, both the saturation magnetization and coercivity decrease.     

Effects of Ag layers on the microstructure and magnetic properties of CoPt/BN multilayer films

Ag/[BN/CoPt]5/Ag and [BN/Ag/CoPt]5/Ag thin films were deposited on glass substrates by magnetron sputtering and then annealed in vacuum at 600 ℃ for 30 min.The structures and magnetic properties of CoPt/BN multilayer films were investigated as a function of Ag layer thickness.It was found that the face-centered tetragonal (fct) (001) texture of CoPt was improved greatly by introducing the Ag toplayer or sublayer together with an Ag underlayer.Good (001)-oriented growth,low intergrain interactions as well as...     

Effect of nitrogen pressure on structure and optical properties of pulsed laser deposited BCN thin films

Amorphous boron carbon nitride (BCN) thin films were deposited on Si (100) and quartz substrates by laser ablation of a boron carbide (B₄C) target in nitrogen atmosphere. The effects of the nitrogen pre ssure (p_N2) on the film deposition rate, composition, structure and optical properties were investigated. The film deposition rate was measured by a surface profiler, which increased from 3.4 to 6.25 nm/min at elevated p_N2. Structure and composition of the films were investigated by X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared (FTIR) spectroscopy. FTIR and XPS analyses indicated that the as-deposited BCN films contained B-C, N-C and B-N chemical bonds, implying the formation of ternary BCN compounds. The nitrogen content in the films increased gradually and then saturated up to ∼ 26 at.% at 10 Pa p_N2. The optical band gap (E_g) increased from 3.78 to 3.92 eV with increasing p_N2 from 2 to 15 Pa. The evolution of E_g is in accordance with the change of film compositions and bonding states.     

Soft magnetic properties of (Ni50Fe50)SiO2 granular thin films for high frequency application

series of (Ni50Fe50)x(SiO2)(1-x) films with different volume fraction x was fabricated by magnetron co-sputtering technique. The microstructure, magnetic and electrical properties were investigated systematically by using X-ray diffraction, transmission electronic microscope, vibrating sample magnetometer and the traditional four point measurement method of resistivity. The results show that the samples consist of nano-scaled Ni50Fe50metallic particles with fcc structure uniformly embedded in amorphous insulating SiO2 matrix, and the particle size decreases with the decrease of x . The rapid change of coercivity with x is observed, and a minimum value 160 A·m-1 of Hc was obtained for the sample of x =0.83 with film thickness of 180 nm, which can be contributed to the exchange coupling between nano-scaled Ni50Fe50 particles. At the frequency lower than 1 GHz, the real part μ' of complex permeability keeps about 110 and the image part μ" is less than 15. Besides, this film exhibits high resistivity ρ=263 μΩ·cm, high saturation magnetization 4π Ms=1.25 T, high in-plane magnetic anisotropy field Hk=6.37 kA·m-1 , and the ferromagnetic resonance (FMR) frequency is estimated to be 2.8 GHz. Therefore, this film can be used in high frequency devices operating over 2 GHz.     

Modifying factor for determining broadband complex permeability of magnetic thin films

A new method of the modifying factor for determining the broadband complex permeability of magnetic thin films, was proposed. Based on the measurement technology of shot-end microstrip line and the new modify factor, a series of FeCo-based magnetic thin films deposited on the oxidized silicon substrates and with an in-plane uniaxial anisotropy were measured in the frequency range of 0.5-5 GHz. The results fit well with the Landau-Lifchitz-Gilbert theory in a broad frequency range.     

热解温度对镧、锰共掺杂铁酸铋薄膜铁电性能的影响(英文)

在不同热解温度下,采用溶胶-凝胶法在Pt/Ti/SiO2/Si衬底上制备镧、锰共掺杂铁酸铋铁电薄膜Bi0.9La0.1Fe0.95Mn0.05O3(BLFMO)。利用热失重仪(TGA)分析BLFMO原粉的质量损失,用 X 射线衍射仪(XRD)和原子力显微镜(AFM)分析 BLFMO 薄膜的晶体结构和表面形貌。在热解温度为420℃时,得到BLMFO薄膜的剩余极化值为21.2μC/cm2,矫顽场为99 kV/cm,漏电流密度为7.1×10-3 A/cm2,说明薄膜在此热解温度下具有较好的铁电性能。     

Effect of substrate temperature on microstructures and dielectric properties of compositionally graded BST thin films

Compositionally graded Ba1-xSrxTiO3 （BST） （x = 0-0.3） thin films were prepared on Pt/Ti/SiO2/Si substrate at different substrate temperatures ranging from 550 ℃ to 650 ℃ by radio-frequency （rf） magnetron sputtering. The effect of substrate temperature on the preferential orientation, microstructures and dielectric properties of compositionally graded BST thin films was investigated by X-ray diffraction, scanning electron microscopy and dielectric frequency spectra, respectively. As the temperature increases, the preferential orientation evolves in the order： randomly orientation→ （111） → highly oriented （111） （α（111）= 60.2%）. The surface roughness of the graded BST thin films varies with the substrate temperatures. No visible internal interface in the compositionally graded thin films can be observed in the cross-sectional SEM images. The graded BST thin films deposited at 650 ℃ possess the highest dielectric constant and dielectric loss, which are 408 and 0.013, respectively.     

The effect of nitrogen pressure on cathodic arc deposited NbN thin films

NbN thin films were deposited on non-standard grade high speed steel (HSS) (79.90 wt.% Fe, 0.71 wt.% C, 6.09 wt.% W, 4.52 wt.% Mo, 3.95 wt.% Cr, 1.82 wt.% Co, 1.75 wt.% V and a hardness of 65 HRC) using cathodic arc deposition at 0.125, 0.5, 1.0 and 1.5 Pa nitrogen pressures (P_N2), with a bias voltage of − 150 V. X-ray diffraction (XRD), Scanning Electron Microscope (SEM), Nanoindentation and Rockwell C analysis were used to characterize the thin films in order to identify the NbN phases and to investigate the influence of P_N2 on mechanical properties. Hexagonal β-Nb₂N, ε-NbN and δ′-NbN_0.95 are identified in XRD analysis. Hardness values derived by nanoindentation technique are 20 GPa for β-Nb₂N, ε-NbN and 40 GPa for δ'-NbN_0.95. Due to the complexity of phase system special attention was focused on identification of NbN phases by deconvolating the XRD peaks especially at 0.5 Pa in which both ε-NbN and β-Nb₂N were found. Rockwell C analysis revealed that the film adhesion is found to be poor at lower P_N2, due to the brittle nature of β-Nb₂N.     

L10-FePt纳米颗粒的合成、结构与磁性

首先概述了L10-FePt纳米颗粒的普遍制备方法,然后重点总结了降低其相转变温度和直接合成这两个方面的典型实验方法,并回顾了L10-FePt纳米颗粒结构、磁性能与自组装方面的最新研究进展。