Mössbauer investigation of Co-doped Bismuth Ferrite prepared by the solution method

Author(s):  
Puyue Xia ◽  
Jiajun Mo ◽  
Weiyi Liu ◽  
Yanfang Xia ◽  
Min Liu

In this work, [Formula: see text] ([Formula: see text] = 0, 0.08) nanoparticles were synthesized by the solution method and their structural differences were studied. X-ray diffraction results show that the rhombohedral R3c space group and perovskite structures are detected in both samples, accompanied by an impurity phase. The (104) and (110) peaks merge when cobalt ions are doped. The decrease in lattice parameters indicates that the microstructure of the nanoparticles becomes gradually distorted. Mössbauer spectroscopy analysis at room temperature reveals an additional doublet due to the oxygen vacancies in [Formula: see text]. Hyperfine interactions, spatial spin-modulated structures and oxygen deficiencies around iron ions are also reflected in the observed spectra and variations in hyperfine parameters.

2017 ◽  
Vol 62 (2) ◽  
pp. 1231-1234
Author(s):  
R. Yu ◽  
J. Yun ◽  
Y. Kim

AbstractWe studied the coloration and phase transformation of various iron based pigment with cobalt substitution method and heat treatment. First, we synthesized well defined one dimensionβ-Fe/CoOOH nanorods using the solid solution method. Yellowishβ-Fe/CoOOH nanorods were transformed into reddish intermediate states and, finally, black CoFe2O4pigments was obtained. Divalent cobalt ions easily occupied tetrahedral sites. The prepared pigments were well characterized in terms of physical properties by using UV-vis, CIELabcolor parameter measurements, SEM (scanning electron microscopy) and XRD (powder X-ray diffraction). In addition, the magnetization property of the prepared CoFe2O4pigment was confirmed by VSM (vibrating sample magnetometer).


2021 ◽  
Author(s):  
Anna Bovkunova ◽  
Evgeniya S. Bazhina ◽  
Igor Evstifeev ◽  
Yulia V. Nelyubina ◽  
Maxim Shmelev ◽  
...  

Two series of heterometallic LnIII−CuII compounds containing a butterfly-like tetranuclear metal core were synthesized and characterized by X-ray diffraction and magnetometry. The structures of the new compounds were shown to...


2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Jiang Zhang ◽  
Zheng-Hong Huang ◽  
Yong Xu ◽  
Feiyu Kang

The iodine-doped Bi2WO6(I-BWO) photocatalyst was prepared via a hydrothermal method using potassium iodide as the source of iodine. The samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM) and selected area electron diffraction (SAED), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectroscopy (DRS), and photoluminescence (PL) spectroscopy. The photocatalytic activity of I-BWO for the degradation of rhodamine B (RhB) was higher than that of pure BWO and I2-BWO regardless of visible light (>420 nm) or ultraviolet light (<400 nm) irradiation. The results of DRS analysis showed that the I-BWO and I2-BWO catalysts had narrower band gaps. XPS analysis proved that the multivalent iodine species including I0and were coadsorbed on the defect surface of Bi2WO6in I-BWO. The enhanced PL intensity revealed that a large number of defects of oxygen vacancies were formed by the doping of iodine. The enhanced photocatalytic activity of I-BWO for degradation of RhB was caused by the synergetic effect of a small crystalline size, a narrow band gap, and plenty of oxygen vacancies.


2016 ◽  
Vol 3 (11) ◽  
pp. 1351-1362 ◽  
Author(s):  
Zhengyang Zhou ◽  
Lukáš Palatinus ◽  
Junliang Sun

The combination of PXRD and ED is applied to determine modulated structures which resist solution by more conventional methods.


Author(s):  
Anneli Wennman ◽  
Ernst H. Oliw ◽  
Saeid Karkehabadi

Lipoxygenases constitute a family of nonhaem metal enzymes with catalytic iron or, occasionally, catalytic manganese. Lipoxygenases oxidize polyunsaturated fatty acids with position specificity and stereospecificity to hydroperoxides, which contribute to inflammation and the development of cancer. Little is known about the structural differences between lipoxygenases with Fe or Mn and the metal-selection mechanism. APichia pastorisexpression system was used for the production of the manganese lipoxygenase of the take-all fungus of wheat,Gaeumannomyces graminis. The active enzyme was treated with α-mannosidase, purified to apparent homogeneity and subjected to crystal screening and X-ray diffraction. The crystals diffracted to 2.6 Å resolution and belonged to space groupC2, with unit-cell parametersa= 226.6,b= 50.6,c= 177.92 Å, β = 91.70°.


2011 ◽  
Vol 675-677 ◽  
pp. 1025-1029
Author(s):  
Hui Zhang ◽  
Xiao Meng Lü ◽  
Jian Lin Ding ◽  
Ji Min Xie ◽  
Chang Hao Yan

Using Y2O3, Mn(CH3COO)2·4H2O as raw materials and glacial acetic acid as solvents, YMnxFe1-xO3 precursors (x= 0, 0.05, 0.1, 0.3, 0.5) have been prepared under 80°C water bath conditions. Perovskite YMnxFe1-xO3 samples were achieved after calcination over 900 °C for 4 h. Structure of the samples was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Ultraviolet obvious diffuse reflection(UV-vis DRS), and Field-emission scanning electron microscopy (FESEM). Photocatalytic activity of the samples was also investigated. Results showed that all the samples with stable perovskite structure had high light absorption in visible-light region, suggesting good visible light harvesting. SEM image showed that the samples were sponge-like and porous agglomerates. Photodecoloration activity of 100 mL Rhodamine B (10 mg/L) was 16~56 % under illumination for 150 min. Oxygen vacancies of the perovskite may explain the high activity of x = 0.1 sample.


1989 ◽  
Vol 4 (3) ◽  
pp. 152-155 ◽  
Author(s):  
T.C. Huang ◽  
J.B. Torrance ◽  
A.I. Nazzal ◽  
Y. Tokura

AbstractRoom temperature crystalline structures of La2-xSrxCuO4 samples with uncommonly high hole concentrations (p) up to p=0.4, annealed under 1 and 100 bars of oxygen pressure have been analyzed by X-ray diffraction. Results show that the x=0 sample with p=0.09 and superconducting below 20K is orthorhombic at room temperature. The orthorhombic distortion at 300K decreases with increasing x and becomes tetragonal when x reaches 0.08. This orthorhombic-to-tetragonal phase transformation is consistent with previous work. Samples with x≥0.28 and p≥0.31 remain tetragonal but are nonsuperconducting down to 5K. Lattice dimension anomalies have also been observed and are correlated with the sudden appearance of oxygen vacancies, as seen by the hole concentration measurements. Initially, the value of the lattice dimension a decreases and c increases monotonically with increasing x. A sudden increase in a and decrease in c begins when x reaches 0.28 for samples prepared under 1 bar of oxygen indicating a sudden loss of oxygen from the structure. This sudden reversal in lattice dimensions a and c is not present in samples annealed under 100 bars of oxygen pressure suggesting essentially no oxygen vacancies. The increase in c with x of the La2-xSrxCuO4 samples with no oxygen vacancies can be attributed mainly to the result of substituting smaller La+3 ions by larger Sr+2 ions. A study of the variation of c with the hole concentration reveals that the c lattice dimension drops sharply with no change in the hole concentration when oxygen is continuously removed from the lattice caused by an increase of the Sr content in La2-xSrxCuO4.


2009 ◽  
Vol 08 (03) ◽  
pp. 285-287 ◽  
Author(s):  
M. ESKANDARI ◽  
V. AHMADI ◽  
Sh. AHMADI

In this study, ZnO nanowires are synthesized via ZnO nanorods at low temperature by using zinc acetate dehydrate and polyvinylpyrrolidone as precursor and capping, respectively. We use chemical solution method for synthesis of ZnO nanowires. Samples are characterized by means of scanning electron microscopy and X-ray diffraction. First, the nanorods are prepared at 300°C temperature, and then they are put into the furnace under air atmosphere at 450°C for 2 h. It is observed that nanowires with 20 nm diameter are produced. Photoluminescence spectra of nanorods and nanowires are compared. It shows that intensity of ultraviolet peak in the nanowires decreases but in contrast the intensity of green emission part increases. This is because, the surface effects such as oxygen vacancies increase in the structures of ZnO .


2008 ◽  
Vol 63 (5) ◽  
pp. 543-547 ◽  
Author(s):  
Inés Viera ◽  
Laura Domínguez ◽  
Javier Ellena ◽  
María H. Torre

This work reports the synthesis and characterization of a new copper complex with nadolol, a betablocker aminoalcohol. The stoichiometry found was Na[Cu(nadololate)(CO3)] · H2O. Electronic and vibrational spectroscopy analysis was performed, and the crystal structure of Na[Cu(nadololate)-(CO3)] · H2O was determined by X-ray diffraction.


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