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A new sol-foam-gel method was developed to fabricate La-doped BiFeO3 muttiferroic materials. It was demonstrated that a gradual increase in the content of La-doped into BiFeO3 results in its structure changing from rhombohedral to orthorhombic. A study of other property changes indicates that La-doping in BiFeO3 enhances its ferromagnetism and ferroelectricity. A temperature-dependent magnetization study suggests that the magnetic property of La-doped BiFeO3 samples varied from antiferromagnetic to ferromagnetic as the content of La-doped into BiFeO3 increased from 0 to 20%. Unique temperature-dependent zero field cooling (ZFC) and field cooling (FC) magnetization behaviors were observed in 15% La-doped BiFeO3 -- its ZFC temperature-dependent magnetization being ferromagnetic and its FC temperature- dependent magnetization being antiferromagnetic. A possible mechanism of such an interesting M-T behavior is discussed. 相似文献
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By employing scanning probe microscopy,conductive path and local oxygen-vacancy dynamics have been investigated in crosshatched La0.7Sr0.3MnO3 thin films grown onto flat and vicinal LaAlO3(001) single crystal substrates.Consistent with prior studies,the crosshatch topography was observed first by dynamical force microscopy as the epi-stain started to release with increasing film thickness.Second,by using conductive atomic force microscopy(CAFM),conduct... 相似文献
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Two new one-dimensional chains extended by alternate benzenedicarboxylate(BDC) and 4-(2,6-di(pyrazin-2-yl)pyridin-4-yl)benzoate(L~-) connectors, {[Cu(L)(BDC)_(0.5)]·3.5 H_2 O}_n (1) and {[Zn(L)(BDC)_(0.5)] ·H_2 O}_n (2), were solvothermally synthesized. Complex 1 is in triclinic system, space group P1 with a = 9.6456(14), b = 11.1160(16), c = 12.0414(18) ?, α = 106.266(3), β = 92.277(3), γ =108.104(3)°, V = 1166.6(3) ?~3, D_c = 1.603 g·cm~(-3), Mr = 563.00, Z = 2, F(000) = 578, μ = 0.996 mm~(-1), the final R = 0.0575 and wR = 0.1386 for 3704 observed reflections with I 2σ(I). Complex 2 crystallizes in monoclinic, space group C2/c with a = 28.607(5), b = 8.9767(16), c = 19.705(4) ?, β = 125.396(3)°, V = 4125.0(13) ?~3, D_c = 1.674 g·cm~(-3), Mr = 519.79, Z = 8, F(000) = 2120, μ = 1.242 mm~(-1), the final R = 0.0487 and w R = 0.0907 for 2944 observed reflections with I 2σ(I). Resulting from the narrower band gap and broader response to visible light, the CuII-chain exhibits better photocatalytic performance towards the degradation of rhodamine B and methylene blue than those of ZnII-chain. 相似文献
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采用一种新的溶液生长法结合多步包覆法在自制的不同粒径SiO2单分散亚微球表面包覆不同厚度的β-FeOOH涂层,得到单分散β-FeOOH/SiO2核壳结构亚微球.实验结果表明,SiO2核心颗粒尺寸对表面涂层的形态和包覆均匀性有很大影响.当SiO2核心颗粒的平均粒径为250 nm左右时,β-FeOOH表面涂层均匀,颗粒间团聚较少,一次包覆后涂层厚度约为35 nm.涂层中β-FeOOH纳米棒的尺寸随着所选SiO2核心颗粒粒径的增大而相应增大.经多次包覆能够显著提高涂层的厚度,3次包覆后β-FeOOH表面涂层厚约100 nm.β-FeOOH/SiO2核壳结构亚微球与质量分数5%的NaOH溶液反应后,于600℃焙烧2 h得到了单分散α-Fe2O3空心微球.单分散α-Fe2O3空心亚微球表层是由α-Fe2O3纳米棒搭建而成的三维网络结构,α-Fe2O3纳米棒的尺寸与核壳结构中β-FeOOH纳米棒的尺寸基本一致. 相似文献