Microstructure of Sm-Fe Films Electrodeposited in a High Static Magnetic Field

Sm-Fe alloy films were electrodeposited in a high static magnetic field with the magnetic flux is perpendicular to the electric current.The samples were prepared on Cu substance in an aqueous solution by constant voltage method.The magnetic flux density used in the experiments were 0 T,2 T and 4 T,respectively.The microstructures,preferential orientation,composition of samples were characterized by SEM(equipped with EDS),AFM and XRD,respectively.The results showed that the thickness of films increased,whereas the concentration of Sm in films ascended first and then descended with the increasing of the flux density.The crystal grains were coarsened under the magnetic fields.The morphology of grains changed from granular at 0 T,to rough at 2 T and to cauliflower like at 4 T.The AFM results confirmed the different roughness of samples.However,the external field has not influenced the orientation of samples significantly.

Electrochemical Preparation of La-Fe Alloy Films in Dimethylsulfoxide (DMSO)

The cyclic voltammetry and potential step methods were used to investigate the electrochemical behavior of Fe 2+ and La 3+ in FeCl 2 LiCl DMSO and LaCl 3 LiCl DMSO systems on Pt, Cu and Ni cathodes. The electroreduction of Fe 2+ to Fe is irreversible in one step,while the electroreduction of La 3+ to La is quasi reversible. The diffusion coefficient of La 3+ in LaCl 3 LiCl DMSO system at 298 K was 3 1×10 -6 cm 2·s -1 . The diffusion coefficient and transfer coefficient of Fe 2+ in FeCl 2 LiCl DMSO system at 298 K were 2 54×10 -6 cm 2·s -1 and 0 24, respectively. La Fe alloy films containing La from 22 7% to 37 1% (mass fraction) were prepared by potentiostatic electrolysis on Cu substrates at a deposition potential from -1 750 to -2 450 V (vs SCE). The fine La Fe alloy films were also obtained by pulse electrolysis at a pulse current densities from 2 to 6 mA·cm -2 . The surfaces of these alloy films are smooth, adhesive and uniform, and have metallic luster.

The effect of deposition temperature on the intermixing and microstructure of Fe/Ni thin film

The physical vapour deposition of Ni atoms on α-Fe（001） surface under different deposition temperatures were simulated by molecular dynamics to study the intermixing and microstructure of the interracial region. The results indicate that Ni atoms hardly penetrate into Fe substrate while Fe atoms easily diffuse into Ni deposition layers. The thickness of the intermixing region is temperature-dependent, with high temperatures yielding larger thicknesses. The deposited layers are mainly composed of amorphous phase due to the abnormal deposition behaviour of Ni and Fe. In the deposited Ni-rich phase, the relatively stable metallic compound B2 structured FeNi is found under high deposition temperature conditions.

Effect of magnetic field on segregation behavior of α-Fe particles in Cu-Fe thin film prepared by magnetron sputtering

The segregation behavior of α-Fe particles in Cu-Fe film prepared by magnetron sputtering was studied by X-ray scattering and X-ray diffraction. The results show that the roughness of the film surface increases with the sputtering time increasing. The as-sputtered films are super saturation solid solution of Cu-Fe. After annealing at 500℃, α-Fe particle can be segregated from the Cu matrix. The orientations α-Fe particles in the annealed film without magnetic field are random. But the clear texture of α-Fe particles in the annealed film with magnetic field is formed, and the 〈001〉 direction of α-Fe particles tends to be parallel to the magnetic field direction.

Magnetic properties and structure of Ni_80Fe_20/Ni_48Fe_12Cr_40 bilayer films deposited on SiO_2/Si(100) by electron beam evaporation

Ni80Fe20/Ni48Fe12Cr40 bilayer films and Ni80Fe20 monolayer films were deposited at room temperature on SiO2/Si（100） substrates by electron beam evaporation. The influence of the thickness of the Ni48Fe12Cr40 underlayer on the structure, magnetization, and magnetoresistance of the Ni80Fe20/Ni48Fe12Cr40 bilayer film was investigated. The thickness of the Ni48Fe12Cr40 layer varied from about 1 nm to 18 nm while the Ni80Fe20 layer thickness was fixed at 45 nm. For the as-deposited bilayer films the introducing of the Ni48Fe12Cr40 underlayer promotes both the （111） texture and grain growth in the Ni80Fe20 layer. The Ni48Fe12Cr40 underlayer has no significant influence on the magnetic moment of the Ni80Fe20/Ni48Fe12Cr40 bilayer film. However, the coercivity of the bilayer film changes with the thickness of the Ni48Fe12Cr40 undedayer. The optimum thickness of the Ni48Fe12Cr40 underlayer for improving the anisotropic magnetoresistance effect of the Ni80Fe20/Ni48Fe12Cr40 bilayer film is about 5 nm. With a decrease in temperature from 300 K to 81 K, the anisotropic magnetoresistance ratio of the Ni80Fe20 （45 nm）/Ni48Fe12Cr40 （5 nm） bilayer film increases linearly from 2.1% to 4.8% compared with that of the Ni80Fe20 monolayer film from 1.7% to 4.0%.

Electrodeposition of Pr-Fe alloy films in urea-dimethylsulfoxide

Cyclic voltammetry and chronoamperometry were used to investigate theelectrochemical behavior of Pr^(3+) ions in a system of 0.01 mol centre dot dm^(-3) Pr(CH_3SO_3)_3 +0.01 mol centre dot dm^(-3) FeCl_2 + 3.0 mol centre dot dm^(-3) urea + DMSO on a R electrode. Someelectrochemical parameters were measured. Potentiostatic depositions between -1.6 and -2.4 V wereapplied to deposit Pr-Fe films in urea-DMSO mixed solution. The Pr content in the alloy films was inthe range of 34.89 wt. percent to 37.15 wt. percent. The Pr-Fe alloy films are proven to beamorphous by XRD (X-ray diffraction).

Preparation and Characterization of Nanotitanium Dioxide Coating Film Doped with Fe^(3+) Ions on Porous Ceramic

The nanotitanium dioxide （TiO2） photocatalytic and porous ceramic filtering technique is one of the advanced methods to effectively treat organic wastewater. The TiO2 sol doped with Fe^3＋ ions was prepared by sol-gel processing. The influences of the process conditions of coating nanophotocatalytic material- Fe^3＋-TiO2 film on the surface of porous ceramic filter by dipping-lift method on the performance of porous ceramic filter were studied. The porous ceramic filters have two functions at the same time, filtration and photocatalytic degradation. The results of this study showed that the pH and viscosity of the sol, amount of Fe^3＋ ions doped as well as the coating times greatly affect the quality of coating film, the performance parameters and the photocatalytic activity of the porous ceramic filter. When the pH of the sol is 3-4, the viscosity is about 6 mPa.S, the amount of doped Fe^3＋ ions is about 2.0 g/L, the porous ceramic filter has been shown to have the best filtering performance and photocatalytic activity. In this condition, the porosity of porous ceramic is about 42.5%, the pore diameter is 8-10μm. The degradation of methyl-orange is 74.76% under lighting for 120 rain.

EFFECTS OF TREATMENT TEMPERATURE ON THE MICROSTRUCTURE AND MAGNETIC PROPERTIES OF Fe-N THIN FILMS

Fe-N thin films were fabricated on both 100Si and NaCl substrates by RF magnetron sputtering under low nitrogen partial pressure. The microstructure and magnetic properties of Fe-N thin films were investigated with the increase of the substrate temperature （Ts） and the annealing temperature （Ta）. It is more difficult for nitrogen atoms to enter the Fe lattice under higher Ts above 150℃. The phase evolution is visible at higher Ta above 200℃. The phase transformation of α＇＇-Fe16N2 occurred at 400℃. The change of crystal size with Ta was clearly visible from bright and dark field images. The clear high-resolution electron microscope （HREM） images of 110α, 111γ＇, 112α＇＇, and 200α＇＇ phases were observed. The interplanar distances from TEM （transmission electron microscope） and HREM match the calculated values very well. From the results of the vibrating sample magnetometer （VSM）, the good magnetic properties of Fe-N films were obtained at 150℃ of Ts and 200℃ of Ta, respectively.

Reduction of Coercivity of Fe-N Soft Magnetic Film by Heat Treatment

200 nm thick Fe-N magnetic thin films were deposited on glass substrates by RF sputtering. The as-deposited films have high saturation magnetization but their coercivity is also higher than what is needed Therefore it is very important to reduce coercivity. The samples were vacuum annealed at 250℃ under 12000 A/m magnetic field. When the N content was in the range of 5-7 at. pct, the thin films consisted of α' +α' after heat treatment and had excellent soft magnetic properties of 4πMs=2.4 T, HC <80 A/m. However, the thickness of a recording head was 2μm, and Hc increased as thickness increased. In order to reduce the Hc, the sputtering power was raised from 200 W to 1000 W to reduce the grain size. 2μm Fe-N thin films were vacuum annealed under the same condition, when the N content was in the range of 5.9-8.5 at. pct, the thin films kept its excellent magnetic properties of 4πMs=2.2 T, HC <80 A/m. The properties of the films meet the need of a recording head material used in the dual-element GMR/inductive heads.

Deposition and Magnetic Properties of Fe_3O_4/Fe/Fe_3O_4 Tri-layer Films

The Fe_3O_4/Fe/Fe_3O_4 (MIM) tri-layer films (200 nm/12-93 nm/200 um) were prepared on Si(100) by DC-magnetron reactive-sputtering followed by air- or vacuum-annealing at 280-400℃ for 1.5 h, respectively. Magnetic properties and phases under different sandwich and annealing conditions were studied. In MIM structure, the incorporation of the interlayer iron does increase the magnetization measured under 8 kOe (M_8K), but reduce coercivity (H_c). The H_c of asdeposited films decreases from 354 Oe to 74 Oe; while M_8K increases from 254 to 392 emu/cc. By annealing in air, the whole MIM tri-layer film becomes γ-F_e2O_3, H_c is about 550 O_e and M_8K is around 250 emu/cc. The coercivity mechanism of as-deposited and annealed MIM trilayer films belongs to domain-wall pinning type. δM plots show that when the interlayer Fe thickness is 12 um, the Fe and Fe_3O_4 layers are decoupled in the as-deposited and annealed states; while it is coupled in the as deposited state when the Fe thickness increases to 23 um. Vacuum annealing of the MIM films leads to increase in both coercivity and magnetization, and to enhance the exchange coupling between layers.

Molecular Beam Epitaxy Growth of Tetragonal FeS Films on SrTiO3(001) Substrates

We report the successful growth of the tetragonal FeS film with one or two unit-cell （UC） thickness on SrTiO33（001） substrates by molecular beam epitaxy. Large lattice constant mismatch with the substrate leads to high density of defects in single-UC FeS, while it has been significantly reduced in the double-UC thick film due to the lattice relaxation. The scanning tunneling spectra on the surface of the FeS thin film reveal the electronic doping effect of single-UC FeS from the substrate. In addition, at the Fermi level, the energy gaps of approximately 1.5？meV are observed in the films of both thicknesses at 4.6？K and below. The absence of coherence peaks of gap spectra may be related to the preformed Cooper-pairs without phase coherence.

Optical and Magnetic Properties of Fe_2O_3/SiO_2 Nano-composite Films

Fe2O3/SiO2 nano-composite films were prepared by sol-gel technique combining heat treatment in the range of 100-900 ℃. The particle size was observed by FE-SEM. Optical properties of the films were investigated by UV-visible spectra. Structural and magnetic characteristics were investigated through FT-IR and VSM. The transparency of the Fe2O3/SiO2 nano-composite films decreased with the content of the Fe2O3. Water and organic solvent in the films were evaporated with heat treatment, so the transparency of the films was enhanced under high temperature. It is also found that the saturation magnetization （Ms） of the films increases with the temperature. As the content of the Fe2O3 increases, when the content of the Fe2O3 is around 30wt%, the Ms of the films has a maximum value.

Corrosion behavior of amorphous/nanocrystalline Al-Cr-Fe film deposited by double glow plasmas technique

In order to improve the corrosion resistance of AZ31 magnesium alloy,the amorphous/nanocrystal Al-Cr-Fe film has been successfully prepared on AZ31 magnesium alloy by double glow plasma tech-nology.The amorphous/nanocrystalline consists of two different regions,i.e.,an amorphous layer on outmost surface and an underlying lamellar nanocrystalline layer with a grain size of less than 10 nm.The corrosion behavior of amorphous/nanocrystalline Al-Cr-Fe film in 3.5% NaCl solution is investi-gated using an electrochemical polarization measurement.Compared with the AZ31 magnesium alloy,the amorphous/nanocrystalline Al-Cr-Fe film exhibits more positive corrosion potentials and lower corrosion current densities than that of AZ31 magnesium alloy.XPS measurement reveals that the passive film formed on the Al-Cr-Fe film after the anodic polarization tests is strongly enriched in Cr2O3,Fe2O3 and Al2O3 at outer surface of the film and in the inner layer consists of Cr2O3,FeO and Al2O3.

MICROWAVE PERMEABILITY SPECTRA OF SPUTTERED Fe-Co-B SOFT MAGNETIC THIN FILMS

Permeability characteristics of sputtered soft magnetic Fe40Co40B20 thin films are investigated in the range of O. 5 to 5 GHz by a shortened microstrip transmission line perturbation method. Excellent microwave permeability is achieved at 0.4 Pa argon pressure： fr is 3.32 GHz, the real and imaginary part of permeability at 0.5 GHz are 104 and 61, respectively. In addition, the thickness effect on permeability is also studied. The minimum damping can be achieved at the thinnest film. Different sources contributed to in-plane anisotropy are discussed briefly. The deviation between the peak frequency of the imaginary part and the zero-crossing frequency of the real part of permeability is also presented.

Tunable in-plane spin orientation in Fe/Si(557) film by step-induced competing magnetic anisotropies

the spin-reorientation transition from out-of-plane to in-plane in Fe/Si film is widely reported, the tuning of in-plane spin orientation is not yet well developed. Here, we report the thickness-, temperature- and Cu-adsorptioninduced in-plane spin-reorientation transition processes in Fe/Si （557） film, which can be attributed to the coexistence of two competing step-induced uniaxial magnetic anisotropies, i.e., surface magnetic anisotropy with magnetization easy axis perpendicular to the step and volume magnetic anisotropy with magnetization easy axis parallel to the step. For Fe film thickness smaller than 32 monolayer （ML）, the magnitudes of two effects under various temperatures are extracted from the thickness dependence of uniaxial magnetic anisotropy. For Fe film thickness larger than 32 ML, the deviation of experimental results from fitting results is understood by the strain-relief-induced reduction of volume magnetic anisotropy. Additionally, the surface and volume magnetic anisotropies are both greatly reduced after covering Cu capping layer on Fe/Si （557） film while no significant influence of NaC1 capping layer on step-induced magnetic anisotropies is observed. The experimental results reported here provide various practical methods for manipulating in-plane spin orientation of Fe/Si films and improve the understanding of step-induced magnetic anisotropies.

Preparation of Fe_(3)O_(4) Film by in-situ Oxidative Hydrolysis on Chitosan

The Fe3O4 films were prepared by in-situ oxidative hydrolysis on chitosan. The structures and characteristics of the prepared Fe3O4 films were investigated by X-ray diffractometry （XRD）, scanning electron microscopy （SEM）, atom force microscopy （AFM）, vibrating sample magnetometry （VSM） and thermogravimetric-differentia thermal analysis （TG-DTA）. The results show that, （1） the as-synthesized Fe3O4 films are pure Fe3O4 with cubic inverse spinel structure; （2） the network structured film can be obtained at lower temperature, and the compact particle film at higher temperature; （3） the prepared Fe3O4 films are super-paramagnetic, and the saturation magnetization is improved with increasing the reaction temperature, which is 49.03 emu/g at 80℃; （4） the temperature of phase transformation from Fe3O4 to a-Fe2O3 is about 495℃. Besides, the formation mechanism of Fe3O4 film was also proposed.

Structure and Magnetic Properties of the γ’-Fe4N Films on Cu Underlayers

The γ＇-Fe4N films on Cu underlayers are deposited on the glass and Si substrates by dc magnetron reactive sputtering. The effects of Cu underlayer on the structure, morphology and magnetic properties of the γ＇-Fe4N films are studied. The single-phase γ＇-Fe4N films with Cu underlayers on the glass substrate are obtained, while the mixture of Fe and γ＇-Fe4N is observed on the Si substrate. In comparison with the films without Cu underlayers, the grains of the films with Cu underlayers exhibit a non-uniform size distribution and give rise to a rougher surface. The magnetic measurements indicate that the γ＇-Fe4N films show a good soft ferromagnetic behavior. The enhanced coercivity in the films with Cu underlayers is observed due to the deterioration of the crystallographic structure as well as the rougher surface.

STUDY ON CO-ELECTRODEPOSITION OF Bi-Fe ALLOY FILMS IN ORGANIC BATH

The cyclic voltametry and potentiostatic electrolysis was used to investigate the preparation of Bi-Fe alloy films in LiClO4-DMSO (dimethylsulfoxide) system. The effects of several factors including the potential of deposition, current density and concentration of iron and bismuth in the solution on the Fe content in the alloy deposits were studied. Experimental results indicated that the amorphous alloy films of Bi-Fe containing Fe 4.40wt%-33.67wt% could be prepared by controlling the system composition and deposition conditions. They were gray, uniform, metallic luster and adhered firmly to the copper substrates analyzed by EDS, SEM and XRD. After heat treatment of crystallization at 270℃ for 1h, the crystal phase of Bi-Fe can be found in XRD patterns.

Reactively sputtered Fe_3 O_4 -based films for spintronics

Half metallic polycrystalline, epitaxial Fe3O4 films and Fe3O4 -based heterostructures for spintronics were fabricated by DC reactive magnetron sputtering. Large tunneling magnetoresistance was found in the polycrystalline Fe3O4 films and attributed to the insulating grain boundaries. The pinning effect of the moments at the grain boundaries leads to a significant exchange bias. Frozen interfacial/surface moments induce weak saturation of the high-field magnetoresistance. The films show a moment rotation related butterfly-shaped magnetoresistance. It was found that in the films, natural growth defects, antiphase boundaries, and magnetocrystalline anisotropy play important roles in high-order anisotropic magnetoresistance. Spin injection from Fe3O4 films to semiconductive Si and ZnO was measured to be 45% and 28.5%, respectively. The positive magnetoresistance in the Fe3O4 -based heterostructures is considered to be caused by a shift of the Fe3O4 e g ↑ band near the interface. Enhanced magnetization was observed in Fe3O4 /BiFeO 3 heterostructures experimentally and further proved by first principle calculations. The enhanced magnetization can be explained by spin moments of the thin BiFeO 3 layer substantially reversing into a ferromagnetic arrangement under a strong coupling that is principally induced by electronic orbital reconstruction at the interface.

Oxidation Resistance of Fe-13Cr Alloy with Micro-Laminated (ZrO_2-Y_2O_3)/(Al_2O_3-Y_2O_3) Films

The micro-laminated （ZrO2-Y2O3）/（Al2O3-Y2O3） composite films were prepared on the surface of Fe-13Cr alloy by an electrochemical process and a sintering process alternately. High-resolution field emission scanning electron microscopy （FE-SEM） was used to characterize the laminated films, indicating that the micro-laminated （ZrO2-Y2O3）] （Al2O3-Y2O3） films have nano-structures. SEM, EDS and mass gain measurement were adopted to study the oxidation resistance of films on Fe-13Cr alloy. It is proved that such micro-laminated films are more effective than ZrO2-Y2O3 or Al2O3-Y2O3 films to resist the oxidation of the alloy, and the oxidation resistance is increased with increasing layers in micro-laminated films. These beneficial effects can be contributed to the mechanism, by which such micro-laminated （ZrOE- YEO3）/（Al2O3-Y2O3） composite film combines all the beneficial effects and overcomes all the disadvantages of both ZrOE- Y2O3 film and Al2O3-Y2O3 film during oxidation of alloy.