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Perovskite-type Ba 1− x Sr x Ti 0.9 Sn 0.1 O 3 ( x = 0, 0.06, 0.07, and 0.08) oxides were prepared by conventional solid-state synthesis, and their electrocaloric effect was investigated, revealing that doping by Sr reduces the Curie temperature to ambient values. The largest electrocaloric strength of 0.31 K mm kV −1 was obtained for x = 0.06 at 47 °C, significantly exceeding values displayed by other lead-free ceramics and implying that novel Sr-doped Ba 1− x Sr x Ti 0.9 Sn 0.1 O 3 ceramics are promising materials for ecofriendly refrigeration applications. [ABSTRACT FROM AUTHOR]

Highlights: [•] A novel quaternary chalcogenide KBiCu2S3 has been synthesized via a facile hydrothermal approach. [•] The critical influencing factors for the crystal growth were discussed in detail. [•] The magnetic and electrical properties of KBiCu2S3 were also studied. [•] The band gap of the compound is 1.29 eV. [•] Its photoelectric response was also characterized, which demonstrated the potential for applications in photovoltaic devices. [ABSTRACT FROM AUTHOR]

Abstract: Superconductors Ba1−x K x BiO3 and body-centered double perovskites Ba1−x K x Bi1−y Na y O3 have been selectively synthesized by a facile hydrothermal route. The appropriate ratio and adding sequence of initial reagents, alkalinity, reaction temperature and time are the critical factors that influence the crystal growth of the compounds. The purity and homogeneity of the crystals were detected by the ICP, SEM, EDX and TEM studies. Magnetic measurements show that the superconducting transition temperatures T C of Ba1−x K x BiO3 decrease from 22K (for x =0.35) to 8K (for x =0.55) with increasing the K doping level. [Copyright &y& Elsevier]

Abstract: Double-perovskite oxides R2MnNiO6 (R=Pr, Sm, and Ho) were synthesized under mild hydrothermal conditions. Crystal growths of the samples were sensitive to the alkalinity, the reaction temperature and the time. The X-ray diffraction data show that all the compounds crystallize in the monoclinic structure of space group P21/n. The purity and composition of the crystals are detected by ICP, SEM and EDX analysis. The magnetic studies for all the compounds indicated the dominance of ferromagnetic contribution and revealed a trivalent valence of both Mn and Ni with partial disorder. The T C temperature of the R2NiMnO6 series is depended on the radius of R3+ atoms, which is consistent with the previous reported. [Copyright &y& Elsevier]

Abstract: The perovskite-type oxides La0.5Sr0.5Mn1−x Fe x O3 (x =0.2–0.5) were synthesized under mild hydrothermal conditions. Crystal growths of the samples were sensitive to the Mn-containing precursor, alkalinity and the reaction temperature. All the compounds corresponded to orthorhombic structure of space group Pnma. The curves M vs. T for the compositions with x =0.2, 0.3 and 0.4 indicated the coexistence of ferro- and anti-ferromagnetic contribution. The temperature dependence ρ(T) is semiconducting for all the compounds and explained well by the variable range hopping rather than the adiabatic small polaron hopping. [Copyright &y& Elsevier]

Abstract: A series of red-emitting Eu3+-doped K2LaNb5O15 niobate phosphors with tetragonal tungsten bronze-type structure were synthesized by the solid state reaction method. The structure of new tungsten bronze-type K2EuNb5O15 was identified by Rietveld refinements to crystallize in the tetragonal space group P4bm, which is isostructural to K2LaNb5O15. The relative intensity of the emission from both 5D0→7F2 and 5D0→7F1 increases with increasing Eu3+ ion concentration. The quenching mechanism of the K2La1−x Nb5O15:xEu system was investigated in detail. The relationship between Photoluminescence properties and the TTB-type structure was discussed. The quantum efficiency of K2EuNb5O15 excited under near-UV light (399nm) is 132% of that of commercial Y2O3:Eu3+ (394nm). The results demonstrated K2EuNb5O15 phosphor as a potential candidate for white light emitting diode pumped by near-UV or blue chip. [Copyright &y& Elsevier]

Abstract: A series of red-emitting Eu3+-doped phosphors SrLa2Mg2W2O12 were successfully prepared by the solid state reaction and their luminescence properties were investigated in detail. Under 464nm light excitation, the emission intensity at 613nm increased with the Eu3+ ion concentration rising, and the quenching effect did not appear until the Eu3+ ion concentration reached 25%, and the critical distance was calculated to be 7.74Å. The emission intensity of Sr(La0.75Eu0.25)2Mg2W2O12 is approximately three times higher than that of the commercial red phosphor Y2O3:Eu3+ under the blue light, meanwhile, the quantum efficiency of Sr(La0.75Eu0.25)2Mg2W2O12 is about two times higher than that of Y2O3:Eu3+. The Commission Internationale de l′Eclairage chromaticity coordinate of Sr(La0.75Eu0.25)2Mg2W2O12 is (x=0.660, y=0.340), which is closed to the standard of NTSC (x=0.670, y=0.330). The results indicate that Sr(La1−x Eu x )2Mg2W2O12 could be a potential red phosphor in fabrication of blue chips WLEDs. [Copyright &y& Elsevier]