Effects of (HoxIn1-x)1.9Sn0.1O3 matrix on magnetization of dispersed Fe3O4 nanocrystals

Solid solutions (HoxIn1−x)1.9Sn0.1O3 with x = 0–0.3 were synthesized to employ as dispersion matrix for oleic acid coated Fe3O4 nanocrystals (NCs). The x = 0.05 matrix exhibited a resistance minimum at a non-zero temperature in each temperature dependent resistivity with magnetic fields of 0 and 1 T, and a negative magnetoresistance. The sample of oleic acid coated Fe3O4 NCs dispersed in the x = 0.05 matrix showed enhanced spontaneous magnetization as the factor of ≈1.3 relative to as-synthesized oleic acid coated Fe3O4 NCs

Synthesis and Magnetic Properties of Fergusonite Structured La(NbVMn)O4

The authors have synthesized fergusonite-structured La(Nb0·71V0·04Mn0·25)O4 samples. The samples, consisting of La3+, Nb5+, V5+, Mn4+ and oxygen ions, demonstrated temperature-dependent magnetization that increased with lowering the temperature below ≈200 K, and almost saturated below ≈100 K. At 75 K, the field-dependent magnetization demonstrated sigmoidal curve and reached 3 μB/Mn at 1 T. Such a magnetic behavior can be ascribed to exchange interaction between Mn4+Nb2O11 nanoclusters. The Mn4+ substitution for the V5+ sites of the crystal resulted also in the occupied state above the valence band maximum

The contrasting effect of the Ta/Nb ratio in (111)-layered B-site deficient hexagonal perovskite Ba5Nb4-xTaxO15 crystals on visible-light-induced photocatalytic water oxidation activity of their oxynitride derivatives

Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.The effect of the Ta/Nb ratio in the (111)-layered B-site deficient hexagonal perovskite Ba5Nb4-xTaxO15 (0 <= x <= 4) crystals grown by a KCl flux method on visible-light-induced photocatalytic water oxidation activity of their oxynitride derivatives BaNb1-xTaxO2N (0 <= x <= 1) was investigated. The Rietveld refinement of X-ray data revealed that all Ba5Nb4-xTaxO15 samples were well crystallized in the space group P (3) over bar m1 (no. 164). Phase-pure BaNb1-xTaxO2N (0 <= x <= 1) porous structures were obtained by nitridation of the flux-grown oxide crystals at 950 degrees C for 20, 25, 30, 35, and 40 h, respectively. The absorption edge of BaNb1-xTaxO2N (0 <= x <= 1) was slightly shifted from 720 to 690 nm with the increasing Ta/Nb ratio. The O-2 evolution rate gradually progressed and reached the highest value (127.24 mu mol in the first 2 h) with the Ta content up to 50 mol% but decreased at 75 and 100 mol% presumably due to the reduced specific surface area and high density of structural defects, such as grain boundaries acting as recombination centers, originated from high-temperature nitridation for prolonged periods. Transient absorption spectroscopy provided evidence for the effect of the Ta/Nb ratio on the behavior and energy states of photogenerated charge carriers, indicating a direct correlation with photocatalytic water oxidation activity of BaNb1-xTaxO2N