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In this work, one three-dimensional periodic composite structure consisting of alumina frame and inscribed nickel spheres is proposed for designing the micron composite porous structure. The finite...

A numerical model for evaporation along with internal radiation absorption of a non-spherical droplet is presented. In this model, the VOF method is utilized to trace the interface and the radiative transfer is taken into account by using the Monte Carlo method combined with a contour based interface reconstruction algorithm. Meanwhile, the dynamic mesh technique is applied to increase the computational efficiency. The validated model is used to investigate the radiation absorption inside prolate and oblate water droplets under infrared laser irradiation, and a parametric study for the effects of droplet’s shape and size is presented. The results reveal that the shape of droplet dominates the spectral absorptance when the droplet’s optical thickness is small, but for optically thick droplets, the radiation absorption turns to be dominated by the spectral reflectivity of the irradiated surface. For a deformable droplet under asymmetrically radiative heating, the incident radiation can significantly enhance the heat transfer and evaporation processes. In addition, the assumption of uniform radiation absorption is found to be valid to optical thin droplets, whereas this assumption will underestimate the average interface temperature and evaporation rate of droplets with large optical thickness.

Experimental identification method is a fundamental means of determining the spectral properties of semitransparent materials. A series of distinctly different and independent experimental data is usually required so as to provide multiple constraints to feed the retrieval model. However, for high-transparency and low-absorption materials, directional transmittance measurements may encounter unpredictable temperature gradients due to too many outlets on the heating compartment. And the transmittance measurements in a certain direction may confront the problem of low recognition that the transmittances of samples with different acceptable and reasonable thicknesses are undistinguished. To resolve these problems, a rotating-interface method coupling with an identifying procedure was proposed in this study. The rotating-interface method can provide a means of measuring various directional transmittances without additional outlets in the heating cell. There is barely any influence on the temperature field of the sample. Applied on multilayered specimens with various layers, this method could provide more independent and distinctly different transmittances by using as few specimens as possible. And thus the enough transmittance data was used as constraints to feed the retrieval model, guaranteeing the uniqueness and stability of the result. To verify this method, a C-cut sapphire was measured for the low absorption wavelengths throughout 0.35 to 1.1 μm at temperatures ranging from 300 to 1500 K. And then an experimental identification procedure was performed to retrieve the indexes of refraction and absorption. Considering the incident and detecting solid angles, a Monte-Carlo ray-tracing (MCRT) method was used to predict the experimental transmittances. A genetic algorithm was adopted to search and to optimize the association of refractive index and absorption index, which was brought in the retrieval model of least-square to minimize the difference between the transmittances, measured and predicted. Finally, temperature and wavelength dependence of transmission properties of the C-cut sapphire up to 1500 K were obtained.

For high transparent materials, the difference among the transmittances of various slabs in different thicknesses is very slight since the index of absorption is rather small. However, the divergence of transmittances is very necessary to provide multiple independent constraints for retrieving spectral intrinsic properties from transmitted data with an acceptable accuracy. A Multi-Layer-Combination (MLC) method in which multiple sheets compose a transmitted combination is proposed to provide obviously different transmittances. In this study, the measurements on MLC slabs of C-plane sapphire were performed between 0.8 and 7.0 µm from room temperature to 1800 K. For a given total thickness, the measured results show that the stacking structure of multiple layers can obviously diminish the transmittance, but has no influence on the infrared cutoff and infrared border of high transparency. The spectral refractive indexes and absorption indices within 0.8–5 µm were extracted from transmittance data by minimizing the standard deviation between measurements and predictions. The results indicate that all the properties are wavelength dependent and temperature dependent. Spectral refractive indexes rise regularly with growing temperature and decrease slowly with increasing wavelength. For a researched temperature, the index of absorption levels off in the high transparent interval and climbs steadily in the next spectrum as the wavelength increases. In the tested temperature range of 300–1800 K, the spectral absorption indices rise gradually with increasing temperature. The absorption edge moves forward to the short wavelength infrared from about 3.5 µm at 300 K to about 2.75 µm at 1800 K.

In the pursuit of high-temperature superconductivity like that in cuprates, artificial heterostructures or interfaces have attracted tremendous interest. It has been a long-sought goal to find similar unconventional superconductivity in nickelates. However, as far as we know, this has not yet been experimentally realized. To approach this objective, we synthesized a prototypical superlattice that consists of ultrathin LaNiO3 and La0.7Sr0.3MnO3 layers. Both zero resistance and the Meissner effect are observed using resistive and magnetic measurements of the superlattice. These are experimental indicators for superconductivity in new superconductors. X-ray linear dichroism causes the NiO2 planes to develop electron-occupied x2-y2 orbital order similar to that of cuprate-based superconductors. Our findings demonstrate that artificial interface engineering is suitable for investigating novel physical phenomena, such as superconductivity.

Transition metal doped TiO2 diluted magnetic semiconductors have attracted considerable interest due to their room temperature ferromagnetism. However, most TiO2 films are highly insulating, and thus the magnetic properties can not be controlled by tuning the carrier concentration. This will limit their application in controlling magnetization via electrical gating. Here, we deposit rutile Ti1−xVxO2 (x = 0.03 and 0.05) films with the thickness between 30 and 245 nm by the pulsed laser deposition technique, and observe an obvious room temperature ferromagnetic behavior in all films. The high resolution X-ray photoelectron spectroscopy results indicate that V substituting Ti4+ ions in the TiO2 lattice, with the +3 valence state having two unpaired d electrons, is responsible for the local spin. More importantly, the systemic investigations of transport properties for Ti1−xVxO2 films reveal that the films are n-type and have metallic conductivity with a carrier density of about 1020/cm3. Further studies suggest that the oxygen vacancies play a dual role of contributing to the metallic conductivity of the Ti1−xVxO2 films, and also providing the free electrons to mediate the long-range ferromagnetic coupling between two magnetic polarons. These findings may offer promise for gate-tunable ferromagnetism in future semiconductor spintronics.

A thermal radiative inverse method was used to determine the high-temperature spectral properties of an ultraviolet fused silica from transmittance data for wavelengths from 0.8 to 5 µm. A developed FTIR system used to measure apparent transmittances of the fused silica sample has been designed and built. In order to reduce the system error caused by detector emission and stray radiation, a measurement strategy at high temperatures was proposed. For deriving spectral transport properties from experimental transmittances, the parameter identification principle was described. The results show that spectral properties are both wavelength dependent and temperature dependent. Spectral refractive indexes rise with increasing temperature and decrease with wavelength. Three absorption peaks of spectral absorptive indices respectively at about 1.4 µm, 2.22 µm and 2.75 µm shift toward the far infrared region and vary differently with increasing temperature. In addition, three absorption bands all become broader for temperatures from 20 °C to 900 °C.

It is well acknowledged that the onset of natural convection have significant impacts on transient thermal conductivity measurement of liquids. Aiming at this drawback, a single-sided horizontal method based on the transient hot disk technique is proposed to perform more accurate measurements of liquids by suppressing natural convection during the tests. Theoretical solutions of this proposed single-sided method are deduced, and numerical simulations are applied to obtain quantified effects of natural convections. Some experiments are performed to verify the numerical settings. Water, glycol and methanol are analyzed numerically using both the traditional vertical orientation method and the single-sided horizontal method. Both temperature profiles and velocity profiles are recorded. It is found that the viscosity and the coefficient of thermal expansion of liquid samples are the key factors for the onset of natural convection. For single-sided horizontal method, the temperature boundary is 2 mm thinner and the maximum velocity is an order lower when testing water compared with the results from vertical method. Besides, the average temperature of the sensor recorded in single-sided horizontal method fits better with the standard value for all tested liquid samples. All of these analyses show that the proposed single-sided horizontal method can effectively suppress the onset of natural convection during the measurements.

We study the magnetic properties of an epitaxial growth bilayer composed of ferromagnetic La0.7Sr0.3MnO3 (LSMO) and paramagnetic LaNiO3 (LNO) on SrTiO3 (STO) substrates. We find that the stack order of the bilayer heterostructure plays a key role in the interfacial coupling strength, and the coupling at the LSMO(top)/LNO(bottom) interface is much stronger than that at the LNO(top)/LSMO(bottom). Moreover, a strong spin glass state has been observed at the LSMO/LNO interface, which is further confirmed by two facts: first, that the dependence of the irreversible temperature on the cooling magnetic field follows the Almeida-Thouless line and, second, that the relaxation of the thermal remnant magnetization can be fitted by a stretched exponential function. Interestingly, we also find an exchange bias effect at the LSMO/LNO bilayer below the spin glass freezing temperature, indicating that the exchange bias is strongly correlated with the spin glass state at its interface.

A bidirectionally weighted Monte Carlo method has been developed for radiation transfer in participating media. For every two elementary cells, the radiation exchange is expressed as the weighted c...

Artificial heterostructures based on LaNiO3 (LNO) have been widely investigated with the aim to realize the insulating antiferromagnetic state of LNO. In this work, we grew [(La0.7Sr0.3MnO3)5-(LaNiO3)n]12 superlattices on (001)-oriented SrTiO3 substrates by pulsed laser deposition and observed an unexpected exchange bias effect in field-cooled hysteresis loops. Through X-ray absorption spectroscopy and magnetic circular dichroism experiments, we found that the charge transfer at the interfacial Mn and Ni ions can induce a localized magnetic moment. A remarkable increase of exchange bias field and a transition from metal to insulator were simultaneously observed upon decreasing the thickness of the LNO layer, indicating the antiferromagnetic insulator state in 2 unit cells LNO ultrathin layers. The robust exchange bias of 745 Oe in the superlattice is caused by an interfacial localized magnetic moment and an antiferromagnetic state in the ultrathin LNO layer, pinning the ferromagnetic La0.7Sr0.3MnO3 layers...

C50H92Cl2N12Ni2O14, monoclinic, C2/c (no. 15), a = 25.731(5) Å, b = 9.940(2) Å, c = 26.574(5) Å, β = 114.825(4)°, V = 6169(2) Å3, Z = 4, R gt(F) = 0.0675, wR ref(F 2) = 0.2209, T = 173(2) K.

Hydrogen generation via solar water splitting using a semiconductor photo-electrode has been extensively explored owing to its contribution to the development of renewable energy. Although pure ZnO has many advantages, its wide band-gap limits its use in solar photoelectric applications. Recently, significant advancements have been made in the photoelectrochemical applications due to the development of multi-component heterostructures. In this study, CdO/ZnO/Ag heterostructure films are fabricated via pulsed laser deposition, and their structure, morphology, and photoelectric properties are intensively investigated. The results indicate that the CdO/ZnO/Ag heterostructure thin film exhibits a wide absorption range from ultraviolet to visible light and an enhanced absorption intensity. The photocurrent density of the heterostructure film reaches 0.25 μA/cm2, which is 4.2 times higher than that of pure ZnO film under visible light irradiation. The increased visible light photocurrent response is mainly attributed to the localized surface plasmon effect of Ag nanoparticles. The band structure of CdO/ZnO promotes the transfer of electrons to CdO, which decreases the recombination of electron-hole pairs at the CdO/ZnO interface and increases the photocurrent. A possible mechanism is proposed here to interpret the enhancement of the photoelectric response.

Noble metal nanoparticles (NPs) have received enormous attention since it displays uniquely optical and electronic properties. In this work, we study localized surface plasmon resonances (LSPR) at different thicknesses and substrate temperatures of Ag NPs films grown by Laser Molecule Beam Epitaxy (LMBE). The LSPR wavelength can be largely tuned in the visible light range of 470 nm to 770 nm. The surface morphology is characterized by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The average size of Ag NPs increased with the thickness increased which leading to the LSPR band broaden and wavelength red-shift. As the substrate temperature is increased from RT to 200 °C, the Ag NPs size distribution becomes homogeneous and particle shape changes from oblate spheroid to sphere, the LSPR band displays sharp, blue-shift and significantly symmetric. Obviously, the morphology of Ag NPs films is important for tuning absorption position. We obtain the cubic crystal structure of Ag NPs with a (1 1 1) main diffraction peak from the X-ray diffraction (XRD) spectra. The high resolution TEM (HR-TEM) and selected area electron diffraction (SAED) prove that Ag NPs is polycrystal structure. The Ag NPs films with large range absorption in visible light region can composite with semiconductor to apply in various optical or photoelectric devices.

Interface engineering is a promising method to trigger emergent magnetic order in oxide heterostructures. Here, we report on the electrical and magnetic properties of short-periodic superlattices (SLs) (SrIrO3)n/(SrRuO3)n (n = 1–5) epitaxially grown on the (001)-oriented SrTiO3 substrate. Intriguingly, (SrIrO3)n/(SrRuO3)n superlattices show itinerant ferromagnetism with recovered Curie temperature and magnetic moment in spite of both individual components being antiferromagnetic insulators in ultrathin films ( n ⩽ 3). Moreover, perpendicular magnetic anisotropy (PMA) is observed and can be tuned by the layer thickness n in the superlattices. Enhanced PMA as high as 1.6 × 10 6 erg/cm3 is obtained in the n = 1 superlattice, which is considerably higher compared to that in n = 4 and 5 SLs. Our systematic thickness-dependent studies reveal that the (SrIrO3)/(SrRuO3) interface plays a crucial role in both electrical and magnetic properties. These results indicate n as a knob to tune the PMA of superlattices, paving a way to design functional materials in transition metal oxides.

It is well known that grain-refinement has a positive impact on the mechanical properties of WC-Co cemented carbide. The effect of VC inhibitor and microwave on density, microstructure and mechanical properties of the sintered WC–12wt%Co alloy was investigated in the present study. The ball milled WC-12wt%Co-xVC composites were compressed and fabricated by using microwave sintering method. The experimental results indicate that the microwave sintering cycle was significantly shorter to that of vacuum processing, and the density of bulk alloys increased with VC inhibitor contents and microwave sintering temperatures. Moreover, the microstructure observation of the sintered samples suggests that VC inhibitor had prominent inhibitory action on WC grains in microwave exposure, and the WC average grain size of alloy with 0.7wt%VC inhibitor was 0.43μm when the sintering temperature reached 1420°C. It is also evident that WC-12wt% alloys with an appropriate proportion of VC inhibitor exhibited higher hardness (92.1HRA) and better transverse rupture strength (2380MPa). And finally the mechanism of inhibitory effects on WC grains under microwave irradiation was discussed.

Under H 2 atmosphere, the green strips were prepared from Al–5.8Zn–1.63Mg–2.22Cu–0.12Zr (mass fraction, %) powders by the semi-solid rolling process with a relative density from 76.1% to 88.0%. The role of temperature on microstructure and mechanical properties was investigated. With increasing rolling temperature from 580 to 610 °C, the disappearance of primary powder boundary and isolated pores, inter-diffusion of species and the change of grain boundary were accelerated. Moreover, the mechanism of microstructure evolution changes from the densification dominant regime to the coarsening dominant regime; the amount of η (MgZn 2 ) phase decreased and more Al 2 Cu particles precipitated at grain boundaries. The optimum temperature for semi-solid rolling of Al–5.8Zn–1.63Mg–2.22Cu–0.12Zr powders was determined. The liquid fraction in the range of 53% to 67% corresponds with a high density level of green strips. The present experimental analysis suggests that semi-solid powder rolling can be optimized to manufacture strips with high mechanical properties.

This paper mainly investigates the transient conjugate heat transfer characteristic that the high speed airflow invades into the gap–cavity–gap structure. For this purpose, a simplified and effective quasi-steady approach in order to improve the numerical computational efficiency in multi-domain transient conjugate problems is presented. In this quasi-steady approach the pretty difference of the characteristic time step between the fluid and solid domains is utilized, so the computational expense can be reduced by alternating the solution sequence between coupled convection/conduction analysis and conduction analysis. The control factors to impact on the accuracy of this quasi-steady state method are analyzed further, by analyzing the process that high speed airflow aerodynamically heats the solid cylinder. Based on this quasi-steady approach, the computational fluid dynamics model combined convection, conduction and surface thermal radiation is established. Then, the transient conjugate heat transfer for the gap–cavity–gap structure is discussed. The computational results and the experimental data are compared with each other and the relative errors between them are summarized. After that, during the transient process, the features of the temperature contour inside the structure are discussed. Finally, from viewpoint of initial pressure difference between high speed airflow outside the structure and the cavity, the transient conjugate heat transfer characteristics of this structure are analyzed.

We have grown room temperature ferromagnetic Fe, and Fe,Cu-codoped In 2 O 3 films on sapphire substrates by pulsed laser deposition. The magnetization of the Fe-doped In 2 O 3 films was independent of the thickness and the observed ferromagnetism was almost homogeneous. The addition of Cu caused the films to exhibit obvious thickness dependent magnetization and the ferromagnetism became inhomogeneous. The temperature dependence of the magnetization, X-ray absorption fine structure and magnetic circular dichroism data, clearly established the presence of Fe metal clusters in Fe,Cu-codoped In 2 O 3 films, which contribute to the inhomogeneous ferromagnetism.

The structural and magnetic properties of (Mn, Fe)-codoped ZnO powders as well as thin films were investigated. The X-ray diffraction and magnetic measurements indicated that the higher sintering temperature facilitates more Mn and Fe incorporation into ZnO. Magnetic measurements indicated that the powder sintered in air at 800 °C showed paramagnetic, but it exhibited obvious room temperature ferromagnetism after vacuum annealing at 600 °C. The results revealed that magnetic clusters were the major contributors to the observed ferromagnetism in vacuum-annealed Zn0.98Mn0.01Fe0.01O powder. Interestingly, the room temperature ferromagnetism was also observed in the Zn0.98Mn0.01Fe0.01O film deposited via pulsed laser deposition from the air-sintered paramagnetic target, but the secondary phases in the film were not detected from X-ray diffraction, transmission electron microscopy, and zero-field cooling and field cooling. Apparently, the magnetic natures of powders and films come from different origins.

An absorption-mode Fourier transform ion cyclotron resonance (FT-ICR) mass spectrum exhibits two types of baseline distortion: a slow periodic oscillation even where no signal peaks are present, and additional distortion near signal peaks and proportional to signal magnitude. These distortions interfere with automated peak-picking, unless the baseline systematic variation is much less than baseline rms random noise. We previously showed that the slow oscillation is removed by low-pass filtering. Here, we present a fast, robust, and automated algorithm that flattens the absorption-mode spectral baseline, even in the vicinity of signal peaks. The method begins by defining baseline data values, followed by linear interpolation to generate baseline data values between the defined values, then boxcar smoothing to generate a final baseline spectrum, and final subtraction of that baseline from the original spectrum to yield a baseline-flattened absorption-mode spectrum. We apply the algorithm to a crude oil spectrum (with 8000 peaks) and to a ribonuclease A protein spectrum (with multiply-charged ion isotopic distributions). We identify many more peaks (crude oil) without loss of mass accuracy, and obtain more accurate isotopic distributions (RNase A).

Mn/Ga noncompensated codoped ZnO films were prepared on c-cut sapphire substrates via pulsed laser deposition. The structural, magnetic, transport, and optical properties of the films were then investigated. Addition of the Ga donor increases the electron concentration and enhances the magnetization in these films because of the net negative charge of the special noncompensated codoping, which can adjust the carrier concentration as well as the magnetic moment. Moreover, the Fermi level moves into the conduction band because of the increase in electron concentration, which results in an increase in the optical band gap value, from 3.28 eV for the undoped ZnO film to 3.61 eV for the (Mn,Ga)-codoped ZnO film.

(In1−xNix)2O3 (x = 0.03 and 0.06) powders were prepared by a solid-state reaction and a vacuum annealing process. The air-sintered samples initially showed paramagnetism, and then exhibited obvious room temperature ferromagnetism after vacuum annealing. The ferromagnetic signal almost disappeared after air annealing and reappeared after vacuum annealing. Hence, the ferromagnetism can be switched “on” and “off” by alternate air and vacuum annealing. X-ray diffraction, high-resolution transmission electron microscopy, and field-cooled/zero-field-cooled measurements were performed. These analyses confirmed that there was no detectable trace of Ni or Ni oxide secondary phase in vacuum-annealed (In1−xNix)2O3 samples, and that the Ni ions were incorporated into the indium oxide lattice (substituting the In3+ ions). No ferromagnetic signal emerged from pure In2O3 powders regardless of undergoing vacuum or air annealing. These results revealed that oxygen vacancy and local spin are two factors that indispensably affect the ferromagnetic properties of the Ni-doped In2O3 system.

A novel azobenzene optically polymer (P-DA) was synthesized based on the azo chromophore molecule, chiral reagent L(-)-tartaric acid, acryloyl chloride and methacrylate. The P-DA was characterized by FT-IR, UV-Vis spectroscopy, 1H NMR, DSC and TGA. The P-DA had high thermal stability up to its glass-transition temperature (Tg) of 110 oC and 5 % heat weight loss temperature of 199 oC. The UV-induced trans/cis photoisomerization and reflex-isomerization behaviors were investigated. The results indicated that the P-DA solution could undergo photochromism after irradiated by 365 nm UV light. The optical parameters: refractive index (n), the dielectric constant (ε) and thermal volume expansion coefficient (β) of P-DA were obtained. The thermo-optic coefficients are one order of magnitude larger than those of the inorganic materials, such as SiO2 (1.1×10−5 oC -1 and LiNbO3 (4×10−5 oC -1) and was larger than the organic material such as polystyrene (-1.23×10-4 oC -1) and PMMA (-1.20×10-4 oC -1). The conclusion had a little significance to develop optical communication.

Nonlinear optical (NLO) polyimide and a series of polyimide/silica nanohybrids were synthesized from 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), NLO molecule 4-(4’- nitrophenyl-2-yl) phenyl-1,3-diamine, coupling agent and TEOS via sol-gel method. The TEOS content in the hybrids was varied from 0 to 22.5 wt%. The prepared hybrids were characterized by FT-IR, Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), Scanning Electron Microscopy (SEM) and Transmission Electron Microscope (TEM). The glass transition temperature (Tg) and the decomposition temperature (Td) at 5 % mass loss were in the range 232~365 °C and 335~475 °C, respectively. The results showed that the prepared materials had excellent thermal stabilities. The electro-optic coefficients (γ33) at 832 nm were in the range of 19-34 pm/V and the values remained well. The experimental results indicate that the prepared thin films have good candidate for electro-optical applications.

A novel polyelectrolyte (PLJY) was synthesized based on the azobenzene chromophore containing functional groups (-C=C-) and α-methacrylic acid by radical polymerization. The PLJY was characterized by FT-IR and UV-vis spectroscopy. The thermal property was characterized using the differential scanning calorimeter (DSC). The glass transition temperatures (Tg) was 179.1 oC and showed that the PLJY had excellent thermal stability. Influences of pH values on the UV-Vis absorption spectra of PLJY were studied and polyelectrolyte solution had good pH-sensitivity and H-aggregation behavior. The photoresponsive and thermochromism behaviors were investigated for the azo polyelectrolyte PLJY solution or film. By 256 nm excitation wavelength, the PLJY solution or film appeared photo responsive behavior. At high temperature, the PLJY solution had thermochromic behavior. These results showed that the polyelectrolyte had potential applications in optical information storage and optical switch.

Three types of Na+-mediated hybrid transition metal−alkali complexes possessing special architectures with molecular formulas of [Na(H2O)3(μ-L)Mn](MnL)(ClO4)3·9H2O·(2H3O+) (2), [Na5Mn2(μ-L)2](ClO4)5(H2O)6 (3) and [Na(NiL)2](ClO4)2·5H2O(3H3O+) (4) (H3L = 1,4,7-triazacyclononane-N,N′,N′′-tripropionic acid) were self-assembled from a reaction system containing transition metal, alkali metal and H3L, and were isolated under different crystallization conditions. In these complexes, [ML] units were connected by Na+ ions to form varied 2D layer structures. Na+ ions act as templates for inducing the organization of [ML] moieties into respective special architectures in different fashions. As a comparison, a mononuclear complex [MnL]2[Mn(H2O)6](ClO4)3·8H2O (1) has been isolated without Na+ ions in the reaction system. This fact proved that sodium ions play a vital role in the assembly procedure. These four complexes have been characterized by elemental analysis, IR, UV spectroscopy and single-crystal X-ray diffrac...

(In1−xFex)2O3 (x = 0.02, 0.05, 0.2) powders were prepared by a solid state reaction method and a vacuum annealing process. A systematic study was done on the structural and magnetic properties of (In1−xFex)2O3 powders as a function of Fe concentration and annealing temperature. The X-ray diffraction and high-resolution transmission electron microscopy results confirmed that there were not any Fe or Fe oxide secondary phases in vacuum-annealed (In1−xFex)2O3 samples and the Fe element was incorporated into the indium oxide lattice by substituting the position of indium atoms. The X-ray photoelectron spectroscopy revealed that both Fe2+ and Fe3+ ions existed in the samples. Magnetic measurements indicated that all samples were ferromagnetic with the magnetic moment of 0.49–1.73 μB/Fe and the Curie temperature around 783 K. The appearance of ferromagnetism was attributed to the ferromagnetic coupling of Fe2+ and Fe3+ ions via an electron trapped in a bridging oxygen vacancy.

A series of Zn 1− x Co x O thin films with the atomic fraction, x , in the range of 0.03–0.10 were deposited on glass substrates at room temperature by magnetron co-sputtering technique and subsequently coupled with the post-annealing treatment for half hour at different temperatures (350 °C and 500 °C) under vacuum. A systematic study was done on the structural, optical and magnetic properties of Zn 1− x Co x O thin films as a function of Co concentration and annealing temperature. X-ray diffraction and UV–vis spectroscopy results indicated that there are not any secondary phases and Co 2+ substituted for Zn 2+ of ZnO host. Magnetic hysteresis loops were observed at room temperature, indicating that both the as-deposited samples and the annealed ones exhibit the room temperature ferromagnetism. It was also found that the magnetic saturation moment per Co atom decreases with increasing Co concentration, while the post-annealing treatment can enhance the magnetic moment of the films effectively.

The effects of Ag layers with different locations and thicknesses on the structural and magnetic property of SiO2/FePt multilayer films were investigated. The non-magnetic Ag layer plays an important role in inducing (001) orientation and ordering of FePt grains, as well as the SiO2-doping reducing the grain size and the magnetic exchange coupling between grains. When the 10 nm Ag layer is moved from the bottom to the top of the SiO2/FePt multilayer film, the coercivity gradually decreases; the largest difference between the out-of-plane coercivity and the in-plane one is obtained in the sample of [SiO2(2 nm)/FePt(3 nm)]3/Ag(10 nm)/[SiO2(2 nm)/FePt(3 nm)]2. Furthermore, the location of Ag layers was fixed and the thickness was changed. The XRD curves suggest that the intensity of the (001) peak becomes the strongest with the addition of 10 nm Ag layers.

Ordered [C/CoPt/Ag] 5 thin films with (001) preferred orientation have been deposited onto glass substrates by magnetron sputtering. The effects of the Ag layer on the structural and magnetic properties of the [C/CoPt/Ag] 5 films were investigated. We have found that the presence of C sublayer together with the suitable thickness of Ag sublayer can provide a driving force for the chemical ordering of the L 1 0 CoPt phase, as well as give an opportunity for the (001)-oriented growth of CoPt grains. It was found that the structural and magnetic properties of CoPt films are strongly related to the strain arising from the misfit between Ag and CoPt layers as well as the C atom diffusion. These three element composite films with a high (001)-oriented growth, a strong perpendicular magnetic anisotropy, and a weak intergrain interactions can satisfy the requirements for ultra-high-density perpendicular recording medium.

CoPt/Ag and [C/CoPt]n/Ag thin films have been prepared onto the glass substrates by magnetron sputtering. We investigated the evolution of texture and magnetic properties of CoPt/Ag and [C/CoPt]n/Ag films. The results show that C-doping plays an important role in improving (0 0 1) texture, improving the order parameter S, reducing the intergrain interactions, and making the magnetization reversal mechanism more close to Stoner–Wolfarth rotational mechanism. The growth mechanism of (0 0 1) texture also seems to be related strongly to the films thickness. Our results show that the highly (0 0 1)-oriented films with ordered fct phase have a significant potential for the perpendicular media of extremely high-density recording.

The highly (001) oriented triple system of [CoPt/C] n /Ag films was deposited on glass substrates by DC and RF magnetron sputtering. After annealing at 600°C for 30 min, thin films become magnetically hard with coercivities in the range of 160–875 kA/m because of high anisotropy associated with the L1 0 ordered phase. C doping plays an important role in improving (001) texture and reducing the intergrain interactions. The oriented growth of CoPt films was influenced strongly by the number of repetitions ( n ) of CoPt/C. By controlling the C content and the number of repetitions ( n ) of CoPt/C, nearly perfect (001) orientation can be obtained in the [CoPt 3 nm /C 3 nm ] 5 /Ag 50 nm .

FexPt100−x(30 nm) and [FexPt100−x(3 nm)/ZrO2]10 (x = 37, 48, 57, 63, 69) films with different ZrO2 content were prepared by RF magnetron sputtering technique, then were annealed at 550 °C for 30 min. This work investigates the effect of ZrO2 doping on the microstructural evolution, magnetic properties, grain size, as well as the ordering kinetics of FePt alloy films. The as-deposited films behaved a disordered state, and the ordered L10 structure was obtained by post-annealing. The magnetic properties of the films are changed from soft magnetism to hard magnetism after annealing. The variation of the largest coercivities of [FexPt100−x/ZrO2]10 films with the Fe atomic percentage, x and differing amounts of ZrO2 content reveals that as we increase the ZrO2 content we must correspondingly increase the amount of Fe. This phenomenon suggests that the Zr or O atoms of ZrO2 preferentially react with the Fe atoms of FePt alloy to form compounds. In addition, introducing the nonmagnetic ZrO2 can reduce the intergrain exchange interactions of the FePt/ZrO2 films, and the interactions are decreased as the ZrO2 content increases, the dipole interactions are observed in FePt/ZrO2 films as the ZrO2 content is more than 15%.

Transition metal salts of heteropolyacids have been prepared taking into account the strong acidic and cation exchanging properties of the solid heteropolyacids. The exchange between protons and the transition metal cation is carried out by stirring a suspension of the hydrated heteropolyacid in a solution of the metal acetylacetonate complex in toluene. The exchange occurs on the surface of the solid particles and diffusion of protons and metal cations into the hydrated lattice leads to the substitution of all the protons. The method can be utilized in order to prepare supported vanadyl and copper molybdophosphates from supported heteropolyacids and they have been studied in the catalysis of the oxidative dehydrogenation of isobutyric acid. The effect of vanadyl counter-ions on the catalytic behavior is the same as observed with bulk catalysts but, on the contrary, copper supported molybdophosphate shows an acid catalytic activity not observed with bulk catalysts.

Graft polymerization of acrylic acid (AA) onto poly( l -lactide) (PLLA) film by UV irradiation was carried out to develop surfaces for N-methylene phosphonic chitosan (NMPC) immobilization. The properties of modified films were discussed by colorimetric method, attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), contact angles, atomic force microscopy (AFM) and osteoblast incubation. The results showed that AA solution concentration and irradiation time had effect on the graft carboxyl densities. Comparing the ATR-FTIR images, two new peaks at 1561 cm−1 and 1632 cm−1 proved that NMPC was immobilized on the film surface successfully. The water contact-angles were decreased from 90 ± 5° to 37 ± 5° after modification. The AFM images indicated that the surface of the combined film was rougher than that of untreated film. The grafted film provided an excellent substrate for the growth of osteoblast.

The novel triple system of [CoPt/C]n/Ag films were deposited on the glass substrates using RF magnetron sputtering. The X-ray diffraction results show that the oriented growth of CoPt films was strongly influenced by the thickness of Ag underlayer and C content. In this triple system where Ag underlayer can not only induce phase transition from FCC to FCT of CoPt film, but also induce the (0 0 1)-oriented growth and C-doping also plays an important role in the improving (0 0 1) texture and reducing the intergrain interactions. A nearly perfect (0 0 1) texture and a high perpendicular magnetic anisotropy can be obtained in the [CoPt (3 nm)/C (3 nm)]5/Ag (10 nm) film.

The combined roles of oxygen vacancy and electron doping in mediating local and nonlocal magnetic ordering of Fe doped in In${}_{2}$O${}_{3}$ and Co doped in ZnO have been investigated within first-principles density functional theory. We first show theoretically that two magnetic dopants can be stabilized energetically around an oxygen vacancy, and are ferromagnetically coupled to form a local magnetic polaron. Furthermore, electron doping plays the elegant dual role of further enhancing the ferromagnetic stability of a local polaron, and more crucially, mediating the nonlocal magnetic coupling between two polarons. Finally, we provide experimental evidence supporting these strong predictions.

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.

The trivacant heteropolyanion A-α[PMo9O31(OH2)3]3− spontaneously dimerizes in acetonitrile to form the Dawson complex [P2Mo18O62]6−. A rapid new quantitative preparation of the sodium salt of this Dawson complex is described. In addition, the structure of TBA5[HP2Mo18O62] is given and the featuring data compared with the isomorphous sodium salt (space group C2/c).

A system for the investigation of the magnetic properties of materials under high pressure is fabricated based on diamond anvil cell (DAC) technology. The system is designed with an improved coil arranged around the diamond of a non-magnetic DAC. Using this system, the magnetic transition of ferromagnetic (Fe) sample under increasing pressure can be observed. We successfully obtain the evolution of magnetic properties as a function of applied pressure reaching 26.9 GPa in the Fe sample. A magnetic transition is observed at approximately 13 GPa, which is consistent with the theoretical prediction.

In the title compound, [Cu(N3)2(C27H33N3)], the copper(II) atom is coordinated by five N atoms from the 1,4,7-tribenzyl-1,4,7-triaza­cyclo­nonane ligand and the azide ions in a slightly distorted square-pyramidal geometry.

Fe/Sn-codoped In2O3 powders and films are prepared by a vacuum annealing process and a pulsed laser deposition technique, respectively. The structural and magnetic properties of the samples are investigated. The obvious room-temperature ferromagnetism is observed in both (In0.92Fe0.05Sn0.03)(2)O-3 powders and films, but their magnetic behaviors are very different. The ferromagnetism of the vacuum-annealed powders is partially due to precipitated Fe3O4 impurity. By contrast, the ferromagnetism of the films is intrinsic and does not originate from any magnetic impurity, as confirmed by the extensive x-ray absorption spectroscopy and magnetization studies.

The magnetic and transport properties of a single layer of La0.7Ca0.3MnO3 are compared with one topped with magnetic nanodots formed from oxides of iron. Remarkably enhanced magnetization and metal-insulator transition temperature were observed for the decorated film capped with In2O3. The saturation magnetization increased by ∼35%, and the metal-insulator transition temperature increased from 75 K to 145 K at zero field. However, no enhancement was observed for either the La0.7Ca0.3MnO3 film with uncapped magnetic dots or the bilayer formed from La0.7Ca0.3MnO3 and In2O3.

Fe-doped In2O3 thin films are deposited on sapphire substrates using pulsed laser ablation. The effects of Fe concentration and oxygen partial pressure on the structure, magnetism and transport properties of (In1−xFex)2O3 films are studied systematically. A detailed analysis of the structural properties suggests the substitution of Fe dopant ions with mixture valences and rules out the presence of clusters and secondary phases as the source of ferromagnetism. Systematic investigations of transport properties for (In1−xFex)2O3 films with a wide range of carrier densities reveal that they occur in both metallic and insulating regimes. The insulating films exhibit variable range hopping at low temperatures and show temperature dependent ferromagnetism, which can be explained by bound magnetic polarons mechanism. For the metallic films, the carrier densities play a crucial role in their robust ferromagnetism and the resistivity and magnetization are independent of temperature; the carrier-mediated exchange me...

By the full-potential linearized augmented plane wave method (FP-LAPW), we investigate the electronic structures and optical properties of Fe-doped SnO2 system, including the density of states (DOS), band structure, dielectric function and other optical spectra. The calculation indicates that the Fe doped materials are all direct transition semiconductors with half-metallic property. With the increase of Fe-doping concentration, the Fermi level goes into valence band gradually, and the band gap reduces with the coupling of Fe atoms increasing. Moreover, impurity can change the property of the bond formation to some extent, and make it have metallic bond characteristic. Furthermore, we find that the optical spectrum (such as absorption spectrum), extinction coefficient, etc are blue shifted, corresponding to the imaginary part of dielectric function. The peaks are related to the transition of electrons, which indicates internal relationship between the electronic structures and optical properties theoretically.

Mn and Cr-doped In2O3 films with Sn codoping were deposited on sapphire substrate by pulsed laser deposition. The ferromagnetism of Mn-doped In2O3 films shows reversible behavior, which can be switched between “on” and “off” states by controlling the carrier density via varying Sn concentration. The enhanced ferromagnetism in Cr-doped In2O3 films is observed due to the significant increase in the carrier density with Sn doping, and the saturation magnetization can reach 2.10 μB/Cr. Most importantly, both of the experiment results reveal that the carrier density and the net spin are two crucial factors for producing and tuning ferromagnetism.

In the title complex, [(C4H9)(4)N](2)[ZnBr4], the Zn-II ion is coordinated by four Br atoms, forming a slightly distorted tetrahedral geometry. The Zn-Br bonds range from 2.3986 (11) to 2.4162 (11) angstrom and the Br-Zn-Br angles range from 106.59 (4) to 112.84 (4)degrees. One of the cations is disordered essentially equally over two orientations.