共查询到20条相似文献,搜索用时 31 毫秒
1.
The BiCoxFe1 − xO3 samples have been successfully synthesized by hydrothermal process. The resulting products were characterized by X-ray powder diffraction (XRD), energy dispersive X-ray (EDS), differential thermal analysis (DTA), and physical property measurement system (PPMS).It was found that the magnetization of the obtained products was greatly enhanced by Co substituting for Fe ions. Furthermore, the value of magnetism of BiCoxFe1 − xO3 samples can be adjusted by Fe doping concentration. DTA curve indicates the ferroelectric properties of the obtained BCFO samples are not affected by Co substitution. Therefore, it would be interesting to realize thin films with similar compositions and study their properties in the interest of device applications. 相似文献
2.
The single-layered Fe100 − xPtx films of 30 nm thick with Pt contents (x) of 35-57 at.% are deposited on heated Si (100) substrate at a temperature (Ts) of 620 °C by magnetron co-sputtering. When the Pt content in the Fe-Pt alloy film is 35 at.%, the value of in-plane coercivity (Hc//) is close to perpendicular coercivity (Hc⊥) and both values are about 800 kA/m. The FePt films exhibit perpendicular magnetic anisotropy when the Pt content increases to the values of between 45 and 51 at.%. The perpendicular coercivity, saturation magnetization (Ms) and perpendicular squareness (S⊥) for Fe54Pt46 film are as high as 1113 kA/m, 0.594 Wb/m2 and 0.96, respectively. These magnetic properties reveal its significant potential as perpendicular magnetic recording media. Upon further increasing the Pt content to 57 at.%, the coercivity of the Fe-Pt film decreases drastically to below 230 kA/m and tends to be closer to in-plane magnetic anisotropy. 相似文献
3.
Sachin S. Kulkarni Galymzhan T. Koishiyev Neelkanth G. Dhere 《Thin solid films》2009,517(7):2121-2124
This paper describes the synthesis and characterization of CuIn1 − xGaxSe2 − ySy (CIGSeS) thin-film solar cells prepared by rapid thermal processing (RTP). An efficiency of 12.78% has been achieved on ~ 2 µm thick absorber. Materials characterization of these films was done by SEM, EDS, XRD, and AES. J-V curves were obtained at different temperatures. It was found that the open circuit voltage increases as temperature decreases while the short circuit current stays constant. Dependence of the open circuit voltage and fill factor on temperature has been estimated. Bandgap value calculated from the intercept of the linear extrapolation was 1.1-1.2 eV. Capacitance-voltage analysis gave a carrier density of 4.0 × 1015 cm− 3. 相似文献
4.
Ni48Fe12Cr40(7 nm)/Ni80Fe20(40 nm) bilayer films and Ni80Fe20(40 nm) monolayer films were deposited at ambient temperature on Si(1 0 0)/SiO2 substrates by electron beam evaporation. The effect of annealing on the structure, composition, magnetization and magnetoresistance of the Ni48Fe12Cr40/Ni80Fe20 bilayer films was investigated. The structure of the Ni48Fe12Cr40/Ni80Fe20 bilayer films remains stable for annealing temperature up to 280 °C. For the as-deposited bilayer film the introducing of the Ni48Fe12Cr40 underlayer promotes both the [1 1 1] texture and grain growth in the Ni80Fe20 layer. The annealing promotes the grain growth of the Ni48Fe12Cr40/Ni80Fe20 bilayer films when the annealing temperature exceeds 280 °C. After annealing at a temperature over 280 °C, Cr atoms inside the Ni48Fe12Cr40 layer diffuse into the Ni80Fe20 layer and segregate on the surface of the Ni80Fe20 layer. The Ni48Fe12Cr40 underlayer as a seed layer can enhance the anisotropic magnetoresistance ratio of the Ni80Fe20 layer at a annealing temperature up to 280 °C compared with Ni80Fe20 monolayer film. After annealing at a temperature over 280 °C, however, the anisotropic magnetoresistance ratio of the Ni80Fe20 monolayer films exceeds that of the Ni48Fe12Cr40/Ni80Fe20 bilayer films. For all annealing temperatures, the coercivities of the Ni48Fe12Cr40/Ni80Fe20 bilayer films are smaller than those of the Ni80Fe20 monolayer films. 相似文献
5.
Lead-free thick film negative temperature coefficient (NTC) thermistors based on perovskite-type BaCoIIxCoIII2xBi1 − 3xO3 (x ≤ 0.1) were prepared by mature screen-printing technology. The microstructures of the thick films sintered at 720 °C were examined by X-ray diffraction and scanning electron microscopy. The electrical properties were analyzed by measuring the resistance-temperature characteristics. For the BaBiO3 thick films, the room-temperature resistivity is 0.22 MΩ cm, while the room-temperature resistivity is sharply decreased to about 3 Ω cm by replacing of Bi with a small amount of Co. For compositions 0.02 ≤ x ≤ 0.1, the values of room-temperature resistivity (ρ23), thermistor constant (B25/85) and activation energy are in the range of 1.995-2.975 Ω cm, 1140-1234 K and 0.102-0.111 eV, respectively. 相似文献
6.
Ba(Ti1 − x,Nix)O3 ferroelectric thin films with perovskite structure are prepared on fused quartz substrates by a sol-gel process. Optical transmittance measurements indicate that Ni-doping has an obvious effect on the energy band structure of BaTiO3. It has been found that the refractive index n, extinction coefficient k, and band gap energy Eg of the films are functions of the film composition. The Eg of Ba(Ti1 − x,Nix)O3 decreases approximately linearly as the Ni content increases, which is attributed to the decline of conduction band energy level with increasing the Ni content. On the other hand, n and k both increase linearly with increasing the Ni content because of the increase of packing density. These results indicate that thin films might have potential applications in BaTiO3-based thin-film optical devices. 相似文献
7.
Zhanqiang Liu Fuqiang Huang Junkang Sun 《Materials Science and Engineering: B》2011,176(16):1313-1316
Li3 − xFe2 − xTix(PO4)3/C (x = 0-0.4) cathodes designed with Fe doped by Ti was studied. Both Li3Fe2(PO4)3/C (x = 0) and Li2.8Fe1.8Ti0.2(PO4)3/C (x = 0.2) possess two plateau potentials of Fe3+/Fe2+ couple (around 2.8 V and 2.7 V vs. Li+/Li) upon discharge observed from galvanostatic charge/discharge and cyclic voltammetry. Li2.8Fe1.8Ti0.2(PO4)3/C has higher reversibility and better capacity retention than that of the undoped Li3Fe2(PO4)3/C. A much higher specific capacity of 122.3 mAh/g was obtained at C/20 in the first cycle, approaching the theoretical capacity of 128 mAh/g, and a capacity of 100.1 mAh/g was held at C/2 after the 20th cycle. 相似文献
8.
Pb1-xBixTiO3 (x = 0.0-0.1) compounds were prepared to study the unique dopant effect of bismuth in PbTiO3. Their thermal expansions and structures were investigated by high-temperature X-ray diffraction and X-ray Rietveld method. The results indicated that Bismuth substitution evidently weakened the tetragonality of PbTiO3 solid solution, but increased the spontaneous polarization. Both the enhanced spontaneous polarization and the decreased tetragonality led to small volume shrinkage with temperature rising, where the average volumetric thermal expansion coefficient changed from − 1.99 × 10− 5/°C for pure PbTiO3 to − 0.56 × 10− 5/°C for Pb0.90Bi0.10TiO3. The Curie point of Pb1 − xBixTiO3 was slightly raised compared to PbTiO3 and permitted one to use it in a wide temperature range. 相似文献
9.
Fabrication of Mg2Si1−xGex (x = 0-1.0) was carried out using a spark plasma sintering technique initiated from melt-grown polycrystalline Mg2Si1−xGex powder. The thermoelectric properties were evaluated from RT to 873 K. The power factor of Mg2Si1−xGex with higher Ge content (x = 0.6-1.0) tends to decrease at higher temperatures, and the maximum value of about 2.2 × 10− 5 Wcm− 1K− 2 was observed at 420 K for Mg2Si and Mg2Si0.6Ge0.4. The coexistence of Si and Ge gave rise to a decrease in the thermal conductivity in the Mg2Si1−xGex. The values close to 0.02 Wcm− 1K− 1 were obtained for Mg2Si1−xGex (x = 0.4-0.6) over the temperature range from 573 to 773 K, with the minimum value being about 0.018 Wcm− 1K− 1 at 773 K for Mg2Si0.4Ge0.6. The maximum dimensionless figure of merit was estimated to be 0.67 at 750 K for samples of Mg2Si0.6Ge0.4. 相似文献
10.
Microstructural properties are found to be variant in the BaTiO3 − x films grown on SrTiO3(001) substrate under various oxygen pressures from 2 × 10− 2 Pa to 2 × 10− 5 Pa by laser molecular-beam epitaxy. Transmission electron microscopic studies reveal that the predominant defects in the films change from threading dislocations into (111) planar defects (i.e. stacking faults and nanotwins) by lowering the oxygen pressure. High density of these defects was observed in the BaTiO3 − x film prepared at the oxygen pressure of 2 × 10− 5 Pa, which shows metallic behavior. The relationships between oxygen pressure, microstructure, and electrical properties are established on the basis of oxygen deficiency. The formation of nanotwins in highly oxygen-deficient BaTiO3 − x epitaxial thin films results from accommodating excess oxygen vacancies induced by lowering oxygen pressure. 相似文献
11.
Zn1 − xMgxO thin films of various Mg compositions were deposited on quartz substrates using inexpensive ultrasonic spray pyrolysis technique. The influence of varying Mg composition and substrate temperature on structural, electrical and optical properties of Zn1 − xMgxO films were systematically investigated. The structural transition from hexagonal to cubic phase has been observed for Mg content greater than 70 mol%. AFM images of the Zn1 − xMgxO films (x = 0.3) deposited at optimized substrate temperature clearly reveals the formation of nanorods of hexagonal Zn1 − xMgxO. The variation of the cation-anion bond length to Mg content shows that the lattice constant of the hexagonal Zn1 − xMgxO decreases with corresponding increase in Mg content, which result in structure gradually deviating from wurtzite structure. The tuning of the band gap was obtained from 3.58 to 6.16 eV with corresponding increase in Mg content. The photoluminescence results also revealed the shift in ultraviolet peak position towards the higher energy side. 相似文献
12.
The Gd2(TixZr1 − x)2O7 (x = 0, 0.25, 0.50, 0.75, 1.00) ceramics were synthesized by solid state reaction at 1650 °C for 10 h in air. The relative density and structure of Gd2(TixZr1 − x)2O7 were analyzed by the Archimedes method and X-ray diffraction. The thermal diffusivity of Gd2(TixZr1 − x)2O7 from room temperature to 1400 °C was measured by a laser-flash method. The Gd2Zr2O7 has a defect fluorite-type structure; however, Gd2(TixZr1 − x)2O7 (0.25 ≤ x ≤ 1.00) compositions exhibit an ordered pyrochlore-type structure. Gd2Zr2O7 and Gd2Ti2O7 are infinitely soluable. The thermal conductivity of Gd2(TixZr1 − x)2O7 increases with increasing Ti content under identical temperature conditions. The thermal conductivity of Gd2(TixZr1 − x)2O7 first decreases gradually with the increase of temperature below 1000 °C and then increases slightly above 1000 °C. The thermal conductivity of Gd2(TixZr1 − x)2O7 is within the range of 1.33 to 2.86 W m− 1 K− 1 from room temperature to 1400 °C. 相似文献
13.
Nanocrystalline nickel ferrite with different concentration of Ni and Zn (NixZn1 − xFe2O4 where x = 0.1, 0.3, 0.5) were synthesized using chemical co-precipitation method. The effect of doping ion concentration on physical properties like crystalline phase, crystallite size, particle size, and saturation magnetization are investigated. The X-ray diffraction pattern confirms the synthesis of single crystalline NixZn1 − xFe2O4 nanoparticles. The lattice parameter decreases with increase Ni content resulting in reduction of lattice strain. HRTEM images revealed that the as-prepared nanoparticles were crystalline with particle size distribution in 10-30 nm range. The saturation magnetization show the superparamagnetic nature of sample for x = 0.1 and x = 0.3 whereas for x = 0.5, the material is ferromagnetic. The saturation magnetization value is 23.95 emu/gm for Ni0.1Zn0.9Fe2O4 sample and it increases with increase in Ni content. 相似文献
14.
In this work, a possible way to enhance the epitaxial growth of metastable, tensile strained SixC1 − x layers by the addition of germanium is demonstrated. During ultra-high vacuum chemical vapor deposition growth, the co-mixing of germane to the SixC1 − x precursors was found to enhance the growth rate by a factor of ~ 3 compared to the growth of pure SixC1 − x. Furthermore, an increase of the amount of substitutional incorporated carbon has been observed. Selective SixGeyC1 − x − y deposition processes utilizing a cyclic deposition were developed to integrate epitaxial tensile strained layers into source and drain areas of n-channel transistors. 相似文献
15.
Itzik Shturman 《Thin solid films》2009,517(8):2767-2774
The effects of LaNiO3 (LNO) and Pt electrodes on the properties of Pb(Zrx,Ti1 − x)O3 (PZT) films were compared. Both LNO and PZT were prepared by chemical solution deposition (CSD) methods. Specifically, the microstructure of LNO and its influence on the PZT properties were studied as a function of PbO excess. Conditions to minimize the Pyrochlore phase and porosity were found. Remnant polarization, coercive field and fatigue limit were improved in the PZT/LNO films relative to the PZT/Pt films. Additionally, the PZT crystallization temperature over LNO was 500 °C, about ~ 50 °C lower than over Pt. The crystallization temperature reported here is amongst the lowest values for CSD-based PZT films. 相似文献
16.
The optical and electrical properties of vapour phase grown crystals of diluted magnetic semiconductor Zn1 − xCrxTe were investigated for 0 ≤ x ≤ 0.005. The diffuse reflectance spectra exhibited an increase in the fundamental absorption edge (E0) with composition x and were also dominated by a broad absorption band around 5200 cm− 1 arising from 5T2 → 5E transition. The 5T2 and 5E levels originate from the crystal field splitting of the 5D free ion in the ground state. The electrical resistivity measurements revealed semiconducting behaviour of the samples with p-type conductivity in the temperature range of 200-450 K. 相似文献
17.
Transparent semiconductor thin films of Zn1 − xTixO (0 ≦ x ≦ 0.12) were deposited on alkali-free glass substrates by the sol-gel method. The effects of Ti addition on the crystallization, microstructure, optical properties and resistivity of ZnO thin films were investigated. The as-coated films were preheated at 300 °C, and then annealed at 500 °C in air ambiance. X-ray diffraction results showed all polycrystalline Zn1 − xTixO thin films with preferred orientation along the (002) plane. Ti incorporated within the ZnO thin films not only decreased surface roughness but also increased optical transmittance and electrical resistivity. In the present study, the Zn0.88Ti0.12O film exhibited the best properties, namely an average transmittance of 91.0% (an increase of ~ 12% over the pure ZnO film) and an RMS roughness value of 1.04 nm. 相似文献
18.
We have investigated the structural properties of Si1 − xGex nanocrystals formed in an amorphous SiO2 matrix by magnetron sputtering deposition. The influence of deposition parameters on nanocrystal size, shape, arrangement and internal structure was examined by X-ray diffraction, Raman spectroscopy, grazing incidence small angle X-ray scattering, and high resolution transmission electron microscopy. We found conditions for the formation of spherical Si1 − xGex nanocrystals with average sizes between 3 and 13 nm, uniformly distributed in the matrix. In addition we have shown the influence of deposition parameters on average nanocrystal size and Ge content x. 相似文献
19.
Interfacial reactions and electrical properties of RF sputter deposited HfTaOx high-k gate dielectric films on Si1 − xGex (x = 19%) are investigated. X-ray photoelectron spectroscopic analyses indicate an interfacial layer containing GeOx, Hf silicate, SiOx (layer of Hf-Si-Ge-O) formation during deposition of HfTaOx. No evidence of Ta-silicate or Ta incorporation was found at the interface. The crystallization temperature of HfTaOx film is found to increase significantly after annealing beyond 500 °C (for 5 min) along with the incorporation of Ta. HfTaOx films (with 18% Ta) remain amorphous up to about 500 °C anneal. Electrical characterization of post deposition annealed (in oxygen at 600 °C) samples showed; capacitance equivalent thickness of ~ 4.3-5.7 nm, hysteresis of 0.5-0.8 V, and interface state density = 1.2-3.8 × 1012 cm− 2 eV− 1. The valence and conduction band offsets were determined from X-ray photoelectron spectroscopy spectra after careful analyses of the experimental data and removal of binding energy shift induced by differential charging phenomena occurring during X-ray photoelectron spectroscopic measurements. The valence and conduction band offsets were found to be 2.45 ± 0.05 and 2.31 ± 0.05 eV, respectively, and a band gap of 5.8 ± 05 eV was found for annealed samples. 相似文献
20.
Cd(1 − x)ZnxS thin films have been grown on glass substrates by the spray pyrolysis method using CdCl2 (0.05 M), ZnCl2 (0.05 M) and H2NCSNH2 (0.05 M) solutions and a substrate temperature of 260 °C. The energy band gap, which depends on the mole fraction × in the spray solution used for preparing the Cd(1 − x)ZnxS thin films, was determined. The energy band gaps of CdS and ZnS were determined from absorbance measurements in the visible range as 2.445 eV and 3.75 eV, respectively, using Tauc theory. On the other hand, the values calculated using Elliott-Toyozawa theory were 2.486 eV and 3.87 eV, respectively. The exciton binding energies of Cd0.8Zn0.2S and ZnS determined using Elliott-Toyozawa theory were 38 meV and 40 meV, respectively. X-ray diffraction results showed that the Cd(1 − x)ZnxS thin films formed were polycrystalline with hexagonal grain structure. Atomic force microscopy studies showed that the surface roughness of the Cd(1 − x)ZnxS thin films was about 50 nm. Grain sizes of the Cd(1 − x)ZnxS thin films varied between 100 and 760 nm. 相似文献