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Abstract: The critical properties of the spinel vanadate MnV1.95Al0.05O4 have been investigated by the Kouvel–Fisher method, and critical isotherm analysis. Reliable critical exponents β=0.492(3), γ=0.969(1) and δ=2.951(4) are obtained. Based on these critical exponents, the magnetization-field–temperature data around T C collapse into two independent curves obeying the single scaling equation M(H,ε)=ε β f ±(H/ε β+γ ). Moreover, the critical exponents are confirmed by the field dependence of the magnetic entropy change relation with n=1+(β+1)/(β+γ). The critical behavior of MnV1.95Al0.05O4 agrees with the prediction of the mean-field model with long range interaction. Compared with MnV2O4, the different critical behavior of MnV1.95Al0.05O4 might be because the doped Al ions destroy the collective frustration interaction between V ions. The ferromagnetism of MnV1.95Al0.05O4 is mainly related to the long range ferromagnetic interaction of Mn ions. [Copyright &y& Elsevier]

Abstract: GaN epitaxial layers and nitride-based light-emitting diodes (LEDs) structures with a conventional single low-temperature (LT) GaN buffer layer and multiple Mg x N y /GaN buffer layers were prepared by metalorganic chemical vapor deposition. It was found that crystal quality of the GaN epilayer prepared on multiple Mg x N y /GaN buffer layers was significantly better than that prepared with conventional low-temperature GaN nucleation layer. With the multiple Mg x N y /GaN buffer layers, it was also found that 20mA LED output power can be enhanced by 12%, as compared to the conventional LED. Such an enhancement in output power could be attributed to the reduction of threading dislocation induced nonradiative recombination centers using 12-pairs Mg x N y /GaN buffer layers. [Copyright &y& Elsevier]

Abstract: Unintentionally doped GaN with conventional single low-temperature (LT) AlN buffer layer and with double Mg x N y /AlN buffer layers both were prepared. It was found that we could reduce defect density and thus improve crystal quality of the GaN by using double Mg x N y /AlN buffer layers. GaN with double Mg x N y /AlN buffer layers reveals an asymmetrical reflection (102) and (002) with a smaller full-width at half-maximum (FWHM), and a higher mobility, lower background concentration and lower etching pit density (EPD) than the GaN with the LT-AlN buffer layer. [Copyright &y& Elsevier]

Abstract: Indium nitride (InN) dots grown on sapphires by metal organic chemical vapor deposition (MOCVD) with an In0.08Ga0.92N intermediate layer were demonstrated. Inserting an In0.08Ga0.92N layer between InN and GaN reduced the average size of InN dots, increased the density of InN dots, and prevented the formation of polycrystalline InN or metallic indium. Furthermore, blue shift of the photoluminescence spectrum of InN dots can be identified when inserting an In0.08Ga0.92N intermediate layer, likely because the InN dots with an In0.08Ga0.92N intermediate layer are markedly smaller than InN dots without an In0.08Ga0.92N intermediate layer, indicating the size quantization effect in the dots. [Copyright &y& Elsevier]

Abstract: Serotonin transport abnormalities are implicated in neuropsychiatric disorders. [123I]ADAM ([123I]-2-([2-({dimethylamino}methyl)phenyl]thio)-5-iodophenylamine) is a novel radiotracer that targets serotonin transporters. We assessed the toxicity of [123I]ADAM (18.5MBq) administered in early- and late-phases (8 and 14 day postfertilization, respectively) of pregnancy. The mortality, clinical status, and gross necropsy were measured in pregnant rats, and the fertility index was measured in rat offspring (weight, clinical observations). We found no dosing-related clinical signs. In conclusion, [123I]ADAM was not toxic in an animal pregnancy model. [Copyright &y& Elsevier]

Abstract: Layered misfit cobaltite Bi2Ca2.4Co2O y has been synthesized by a sol–gel method. This compound exhibits large thermoelectric (TE) power (S 300K∼170μVK−1), low resistivity (ρ 300K∼42mΩcm) and relatively small thermal conductivity (κ 300K∼2.8WK−1 m−1) at room temperature. Furthermore, the resistivity of this compound displays a metallic behavior above T ⁎∼150K with a semiconducting behavior below this temperature. This abnormal behavior in resistivity is analogous to those observed in Sr and Ba based misfit cobaltites. The observed features of the TE have been discussed based on the narrow band model. [Copyright &y& Elsevier]

Abstract: Cr-doped CuAlO2 thin films were deposited on sapphire substrates by chemical solution deposition. The polycrystalline phase structure of CuAl1−xCrxO2 (x=0–0.015) thin films was confirmed using an X-ray diffractometer in grazing incidence mode. All specimens are phase-pure. Optical–electrical property measurements show that with increasing Cr amount, electrical resistivity decreases from x=0 to 0.01, followed by an increase of x=0.015. This implies that two mechanisms affecting conductivity coexist and compete with each other. The predominance of the mechanisms changes with the increase in the Cr content. The detailed investigation on the transmittance in the ultraviolet region suggests that Cr doping can modify the structure of the top of valence band (VB) because Cr 3d states contribute to VB. Finally, 1% Cr doping can realize the best optimization of optical–electrical property with respect to transparent conducting oxide thin films. [Copyright &y& Elsevier]

Abstract: Mg-doped CuAlO2 thin films are prepared by the chemical solution method. The XRD results show that the solid solubility of Mg species on Al sites in CuAlO2 lattice is lower than 2at.%. When less than 2at.% of Mg is added to the CuAlO2 film, the surface roughness of the films was reduced with Mg substitution. Moreover, the c-axis orientation of the films improves because the in-plane fusion between CuAlO2 crystallites is hindered. Optical and electrical measurements show that substituting Al3+ in the films with Mg2+ increases both their transmittance in the visible region and their optical band gaps. As well, their electrical conductivity is enhanced. At 300K, the conductivity of the 1at.% Mg-doped sample is up to 5.2×10−3 S/cm. Thus, Mg-doped CuAlO2 films may have potential applications as transparent conductive oxides. [ABSTRACT FROM AUTHOR]

Abstract: Single phase CuAlO2 thin films were first successfully prepared on (0001) sapphire substrates by chemical solution deposition method. Additionally, in order to improve the transmittance and conductivity of single phase CuAlO2 thin films, effects of citric acid as additive on phase structure, morphology and optical–electrical property of CuAlO2 thin films were investigated. Appropriate contents of citric acid do not inhibit the formation of single phase CuAlO2 thin films, and are also in favor of improvement of transmittance. Excessive citric acid not only introduces secondary phases, but also deteriorates the quality of the film surface. The mean transmittance in visible region is approximately 50% in the film prepared with 5unit contents of citric acid and its direct and indirect optical band gaps are 3.24eV and 1.8eV, respectively. The films with or without citric acid behave like semiconductors. The resistivity and the activation energy of the film prepared with 5unit contents of citric acid are evaluated as 2.5×102 Ωcm at 290K and 300.5meV, respectively. [Copyright &y& Elsevier]