Effect of oxygen pressure on electrical transport properties for （110） oriented La2/3Sr1/3MnO3 films directly deposited on silicon

La2/3Sr1/3MnO3 films with(110) preferred orientation were deposited on Si(100) substrate without any buffer layer by pulsed laser deposition technique.Effect of oxygen pressure on orientation,surface morphology,and electrical transport properties were investigated.The film deposited at 10 Pa presented(110) preferred orientation with the best crystalline quality,the largest grain size,and the smallest roughness.The(110) oriented film presented higher metal-insulator transition temperature,and the lower resistivity than that of the samples without preferred orientation.     

Preparation and characterization of La0.8Sr0.04Ca0.16Co0.6Fe0.4O3-δ-La0.9Sr0.1Ga0.8Mg0.2O3 composite cathode thin film for SOFC by slurry spin coating

The La0.8Sr0.04Ca0.16Co0.6Fe0.4O3-δ(LSCCoF)and La0.9Sr0.1Ga0.8Mg0.2O3(LSGM)powders were synthesized by glycine-nitrate combustion process and conventional solid-state reaction method,respectively.The LSCCoF-LSGM composite cathode material was successfully elaborated and deposited on dense pellets of the LSGM electrolyte by means of slurry spin-crating process.The cathode films with the best surface morphology and microstructure were obtained when the operating parameters fixed as follows:the content of ethyl cellulose which acted as pore former and binder is 10 wt.%,the content of terpineol which acted as modifier is 5 wt.%,the speed of rotation rate is3200 r/min and the best post-deposition sintering temperature is 1000 ℃.     

Growth and interface of amorphous La2Hf2O7/Si thin film

Amorphous La2Hf2O7 thin films were deposited on Si(100) substrate by pulsed laser deposition (PLD) method under different con-ditions. The interfacial states of the La2Hf2O7/Si films were studied by synchrotron X-ray reflectivity (XRR) and X-ray photoelectron spec-troscopy (XPS). When grown under vacuum condition, silicate, silicide and few SiOx were formed in the interface layer. However, the Hf-silicide formation could be effectively eliminated by the ambient oxygen pressure during film growth. The result revealed that the La2Hf2O7/Si interlayer was intimately related with growth condition. Insufficient supply of oxygen would cause Hf-silicide formation at the interface and it could be most effectively controlled by the ambient oxygen pressure during film growth.     

Nanoscratch behaviors of La0.7Sr0.3MnO3＋δ thin films

The nanoscratch behaviors of La0.7Sr0.3MnO3＋δ films, which were deposited with ratio of O2/（O2＋Ar）, ranging from 4.4% to 45.6% by DC magnetron sputter, were investigated by a nanoindentation technique. The results indicated that the friction coefficient between the films and the diamond tip depended on the loading critical load. The friction coefficient was about 0.08-0.12 when the loading normal load was less than the loading critical load. The films displayed excellent elastic recovery after unloading. When the loading load was larger than the loading critical load, plastic deformation and ploughing appeared for the films. The friction coefficient was about 0.43 when the film was damaged completely. The suitable decrease in ratio of O2/（O2＋Ar） could improve the nanoscratch resistance of the films. The film deposited with O2/（O2＋Ar）=25% possessed better scratch resistance due to good elastic recovery, high nanohardness, and critical load. The loading critical load of the film was larger than 80 raN.     

Preparation and Characterization of Component Materials for Intermediate Temperature Solid Oxide Fuel Cell by Glycine-Nitrate Process

La1-xSrxGa1-yMgyO3-δ (LSGM) electrolyte, La1-xSrxCr1-yMnyO3-δ (LSCM) anode and La1-xSrxFe1-yMnyO3-δ (LSFM) cathode materials were all synthesized by glycine-nitrate process (GNP). The microstructure and characteristics of LSGM, LSCM and LSFM were tested via X-ray diffraction(XRD), scanning electron microcopy (SEM), A C impedance and four-probe direct current techniques. XRD shows that pure perovskite phase LSGM electrolyte and electrode (LSCM anode and LSFM cathode) materials were prepared after being sintered at 1400 ℃ for 20 h and at 1000 ℃ for 5 h, respectively. The max conductivities of LSGM (ionic conductivity), LSCM (total conductivity) and LSFM (total conductivity) materials are 0.02, 10, 16 S·cm-1 in the air below 850 ℃, respectively. The conductivity of LSCM becomes smaller when the atmosphere changes from air to pure hydrogen at the same temperature and it decreases with the temperature like metal. The porous and LSGM-based LSCM anode and LSFM cathode films were prepared by screen printing method, and the sintering temperatures for them were 1300 and 1250 ℃, respectively. LSGM and electrode (LSCM and LSFM) materials have good thermal and chemical compatibility.     

Solid state reaction synthesis and total electrical conductivity of La_(0.7)Sr_(0.3)Cr_yMn_zCo_(1-y-z)O_(3-δ)

The La0.7Sr0.3CryMnzCo(1-y-z)O3-δ samples were prepared by solid state reaction.The phases,microstructure and properties of the samples were investigated by XRD,SEM,DC four-probe method and iodometry method.The single orthorhombic phase La0.7Sr0.3CryMnzCo(1-y-z)O3-δ perovskite oxides were obtained when sintered at l350 °C for 10 h.The oxygen nonstoichiometry of the materials varied inversely with the total electronic conductivity.The sample with composition of La0.7Sr0.3Cr0.5Mn0.35 Co0.15O3-δ had the maximal total electronic conductivity and the lowest oxygen nonstoichiometry which were 22.4 S/cm and 0.040 at 850 °C,respectively.The low total electronic conductivity is related to the low relatively density of the samples directly.The activation energy of conduction changed at 550 °C,and the activation energy of conduction at high temperature(T550 °C) was higher than that at low temperature range(T550 °C).     

Nanoscratch behaviors of La_(0.7)Sr_(0.3)MnO_(3 δ) thin films

The nanoscratch behaviors of La0.7Sr0.3MnO3 δ films, which were deposited with ratio of O2/(O2 Ar), ranging from 4.4% to 45.6%, by DC magnetron sputter, were investigated by a nanoindentation technique. The results indicated that the friction coefficient between the films and the diamond tip depended on the loading critical load. The friction coefficient was about 0.08–0.12 when the loading normal load was less than the loading critical load. The films displayed excellent elastic recovery after unloading. When the loading load was larger than the loading critical load, plastic deformation and ploughing appeared for the films. The friction coefficient was about 0.43 when the film was damaged completely. The suitable decrease in ratio of O2/(O2 Ar) could improve the nanoscratch resistance of the films. The film deposited with O2/(O2 Ar)=25% possessed better scratch resistance due to good elastic recovery, high nanohardness, and critical load. The loading critical load of the film was larger than 80 mN.     

Effect of film thickness on magnetic properties of Cr/SmCo/Cr films

Cr/SmCo/Cr films with different SmCo thickness were deposited on glass substrates by magnetron sputtering,followed by an annealing process at 550 °C for 20 min.Experimental results showed that the SmCo film of 30 nm exhibited two-phase behavior in the demagnetization process,the obvious kink was observed near zero.For the SmCo film of 50 nm,the kink was invisible,and a single phase like behavior was obtained in the demagnetization process.The reversal behavior became consistent in the thicker films.Moreover,the coercivity reduced and the saturated magnetization increased obviously with the increasing thickness.X-ray diffraction results indicated that the average grain size of SmCo 5 in the thicker films were almost 30 nm,but the quantity of SmCo 5 grains increased with the increasing thickness,which enhanced the intergrain exchange coupling(IEC) of the SmCo 5 hard phases.The increase of IEC improved the magnetic properties of SmCo films with increasing thickness.     

Investigation on the magnetomechanical behavior of trilayered GM actuator

In this article, it was suggested a TbFe/Co/Dy trilayered GM （Giant Magnetostrictive） film type actuator and investigated the magnetomechanical characteristics of the actuator for micro application. The trilayered films were fabricated at different thickness ratios to get an optimized structure. TbFe had positive GM properties, and cobalt, dysprosium layers made the magnetostriction property of composite film increase in low magnetic field. To fabricate the Si based microactuator with trilayered film, micromachining processes including RIE （Reactive Ion Etching） and selective DC magnetron sputtering techniques were combined. The deposited film thicknesses were measured by X-ray diffraction （XRD）. As a result, the magnetization of the film on the fabricated actuator was observed to characterize the magnetic properties of the TbFe/Co/Dy film using VSM （Vibrating Sample Magnetometer）. The magnetostriction of the actuator was determined by measuring the differences of curvature of the film coated silicon substrates using the optical cantilever method, and the deflections were also estimated under the external magnetic field lower than 0.5T for micro-system applications.     

Structure and Waveguide Properties of Sol-Gel Derived Gd2O3 Films

Pure and rare earth doped gadolinium oxide (Gd2O3) waveguide films were prepared by a simple sol-gel process and dip-coating method. Structure of Gd2O3 films annealed at different temperature was investigated by X-ray diffraction and transmission electron microscopy. Oriented growth of (400) face of Gd2O3 has been observed when the films were deposited on amorphous substrate. The refractive index and thickness of films were determined by m-lines spectroscopy. The laser beam (λ= 632.8 nm) was coupled into the film by a prism coupler and the propagation length is about 3.5 cm. Luminescence properties of europium ions doped films were measured by waveguide fluorescence spectroscopy, which shows disordered environment for Eu^3 at 400℃.     

Research on Performance of ZnS：TbF3 Thin Film Electroluminescence Device

The electroluminescence of ZnS doped with terbium fluoride thin films prepared by radio frequency magnetron sputtering method was reported. The characteristics of the ZnS : TbF3 thin film electroluminescence devices, such as film characteristics of the ZnS:Tb active layer, substrate temperatures during magnetron sputtering and Tb concentration of the active layer, were systematically investigated. The results show that annealing can evidently improve the luminescence performance of the luminescence device.     

Band offsets between amorphous LaeHf2O7 and silicon

Amorphous La2Hf2O7 films were grown on Si(100) by pulsed laser deposition method. The valence and conduction band offsets between amorphous La2Hf2O7 film and silicon were determined by using synchrotron radiation photoemission spectroscopy. The energy band gap of amorphous La2Hf2O7 film was measured from the energy-loss spectra of O 1s photoelectrons. The band gap of amorphous La2Hf2O7 film was determined to be 5.4±0.2 eV. The valence and the conduction-band offsets of amorphous La2Hf2O7 film to Si were obtained to be 2.7±0.2 and 1.6±0.2 eV, respectively. These results indicated that the amorphous La2Hf2O7 film could be one promising candidate for high-k gate dielectrics.     

Humidity sensing properties of La^3＋ and K^＋ co-doped Ti0.9Sn0.1O2 thin films

The humidity sensing properties of La3+ and K+ co-doped Ti0.9Sn0.1O2 thin films were investigated. The humidity sensitive thin films were prepared by sol-gel method on alumina substrates. The sensing behaviors of thin films were inspected at different sintering temperatures by constructing a humidity-impedance measuring system. It was found that the addition of rare earth ion La3+ and alkali ion K+ was beneficial for improving the humidity sensitive properties of the samples and La0.003K0.5Ti0.9Sn0.1O2 sintered at 500 ℃ for 4 h showed the best humidity sensing properties. The impedance of this thin film decreased from 109 to 104 Ω with excellent linearity in the humidity range of 11%-95%. Narrow hysteresis loop, prominent stability and high sensitivity were obtained. The effects of dopant con-tent and doping mechanism on humidity sensitivity were also discussed in terms of segregation of rare earth ions at grain boundaries and granularity of crystalline and influence of K+ on the decrease in the intrinsic resistance of the materials, and increase in the number of wa-ter adsorption sites.     

Study on Properties of LSGM Electrolyte Made by Tape Casting Method and Applications in SOFC

Solid oxide fuel cell is attracting more attention in recent years for its lower pollution emission and high energy convert efficiency. La0.9Sr0.1Ga0.8Mg0.2O3-δ is a new kind of electrolyte for intermediate temperature SOFC. In this paper, La0.9Sr0.1Ga0.8Mg0.2O3-δ (LSGM) was prepared by solid state reaction method and formed by tape casting process to make a planar electrolyte. The appropriate amount of the dispersive was obtained by viscosity test. The densities of sintered samples increase with the increasing sintering temperature. It was found that the relative density of electrolyte can approach the value of 95% by the isostatic pressing treatment of the green tape. The average thermal expansion coefficient of the LSGM is 11.4×10-6/℃ at temperature range (200～1200 ℃). Measurements of the current-voltage and power-current characteristics of the H2-Air cell show that the open-circuit voltage is 1.067 V at 800 ℃, peak current density is 0.56 A·cm-2 and the maximum power output is 0.147 W·cm-2.     

Electrical Properties and Microwave Synthesis of Mixed Rare Earth Oxide Ln0.7Sr0.3-xCaxCo0.9Fe0.1O3-δ

In order to lower the raw materials cost and develop a novel cathode materials for intermediate temperature solid oxide fuel cell(ITSOFC), using mixed rare earth replacing the expensive pure La2O3 as the raw materials, the powders of Ln0.7Sr0.3-xCaxCo0.9Fe0.1O3-δ (Ln=the mixed rare earth, x=0.05, 0.10, 0.15) for the applications as the cathode materials were prepared by microwave sintering process. The crystal structure and the particles morphology of the obtained powders were characterized by XRD and SEM, the electrical conductivity of all samples sintered at 1200 ℃ for 3 h was also measured as the function of the temperature from 100 to 800 ℃ by DC four-probe method in air. The experimental results show that due to the influence of mixed rare earth the powders of Ln0.7Sr0.3-xCaxCo0.9Fe0.1O3-δ synthesized at 1200 ℃ for 0.5 h with the mean particle size of 1～20 μm was of perovskite and cubic fluorite phase as well a little SrO phase, the electrical conductivity of the samples decreases with the adding Ca2+ content, and are all higher than 100 S·cm-1 from 500 to 700 ℃ when x≤0.10. Ln0.7Sr0.3-xCaxCo0.9Fe0.1O3-δ. Can meet the demand of the electrical properties for the cathode materials in ITSOFC.     

Characterization of Micro and Nano-Scaled Co/Ni Bi-Layered Films Electrodeposited Under Influence of Magnetic Field:Effects on Structure and Morphology

In this study,the possibility of obtaining micro and nano-scaled Co/Ni bi-layered films by use of the electrochemical method was investigated.The electrodeposition process was performed with presence and absence of a uniform external magnetic field up to 1T to examine its influence on structure and morphology of the obtained thin films.Afterwards,each sample was annealed under high magnetic field with strength up to 12 T at 623 K,what allowed compare and determine the changes in morphology and structure,before and after heat treatment.The Co/Ni bi-layered thin films were deposited onto an indium-doped tin oxide(ITO)-coated conducting glass substrate from sulfate baths with boric acid as an additive.The results show drastic changes in the morphology between macro and nano-scaled films which were strongly affected by an introduction of the magnetic field to the electrodeposition process.The annealing process allowed to determine the nucleus transition and showed that under the high temperature treatment it is possible to control the growth mode as well as the phase composition changes.     

Ultraviolet-shielding and conductive double functional films coated on glass substrates by sol-gel process

Ultraviolet-shielding and conductive double functional films were composed of CeO2-TiO2 film and SnO2:Sb film deposited on glass substrates using sol-gel process.Ce(NO3)3·6H2O and Ti(C4H9O4),SnCl4 and SbCl3 were used as precursors of the two different functional films respectively.The CeO2-TiO2 films were deposited on glass substrates by sol-gel dip coating method,and then the SnO2:Sb films with different thickness were deposited on the pre-coated CeO2-TiO2 thin film glass substrates,finally,the substrates coated with double functional films were annealed at different temperatures.The optical and electrical properties of the CeO2-TiO2 films and the double films were measured by UV-Vis spectrometer and four probe resistance measuring instrument.The crystal structures and surface morphology of the films were characterized using XRD and optical microscope,respectively.The obtained results show that the ultraviolet-shielding rate of the glass substrates with CeO2-TiO2 films is not less than 90%,and transmittance in visible lights can reach 65%.With the thickness of the SnO2:Sb film increasing,its conductivity became better,and the surface resistance is about 260 Ω/ when the SnO2:Sb films were deposited 11 cycles of the dip on the pre-coated CeO2-TiO2 glass.The ultraviolet-shielding rate of the glass substrates with double functional films is higher than 97%,and the peak transmittance in the visible lights is 72%.Additionally,with increasing the heat treatment time,the Na+ of the glass substrates diffuses into the films,resulting in the particle size of SnO2 crystal smaller.     

气体辅助法陶瓷薄膜的制备

Ceramics （alumina） coating on sevaral materials has been successfully achieved at room temperature by gas - assisted deposition （ GAD） technique. In the GAD process the alumina powder was accelerated by jet flow with velocity of - 1000 m/s and impaeted to a substrate, thereby a fiat and dense film was deposited up to 10 μm on the substrate without arty additional heating. The crystal structttre of the alumina in an obtained GAD films seemed as amorphous like. The crystalline phase was recovered by post nnnenling at 1 300 ℃ , however, the matrix resulted in a hollow structure.     

Microstructure and variable emittance property of annealed La-Sr-Mn-O films

The La-Sr-Mn-O films were deposited on Si(100) substrates by DC magnetron sputtering and followed by air annealing at 973 K for 1 h.The microstructure and temperature dependence of total hemispherical emittance ( H) of the annealed La-Sr-Mn-O films prepared at various processing parameters were investigated.The results indicated the films deposited at lower sputtering pressure and lower O2/(O2+Ar) volume proportion (RO) were present in rhombohedral perovskite structure and the length of Mn-O bond was shorter.The metal-insulator transition temperature (TMI) was higher.All of the annealed films showed the unique feature of variable emittance based on metal-insulator transition.The films showed low emittance at low temperature but high emittance at high temperature.Moreover,the H significantly changed in the vicinity of TMI.The variability of total hemispherical emittance (Δε) and the temperature range with obvious emittance change could be adjusted by changing the processing parameters.The Δεcould be 0.45 andΔε/ε355 ( 355 is the εH at 355K) exceeded 50% for the annealed La-Sr-Mn-O films.Therefore,the annealed La-Sr-Mn-O films showed much potential for thermal control applications as smart thermochro-mic variable emittance materials.     

Effect of Zn Doping on Transport Properties of La2/3 Sr1/3 Mn1 - x Znx O3 Films

La2/3 Sr1/3 Mn1-x ZnxO3films （x =0.05, 0.1,0.3, and 0.5） were prepared using magnetron sputtering method, and the effect of Zn doping on transport properties of the films was studied. An analysis of X-ray diffraction showed that the main phase of the bulk target was orthorhombic and the films had better epitaxial character. It was found that the films with x =0.05 and x =0.1 exhibited typical insulator-metal transition. No transition of the films with x≥0.3 was observed and the dominant transport was variable-range hopping due to observable secondary phase ZnO. These could be attributed to the Zn doping effect on manganites.