Infrared and Electronic Spectra of Rare Earth Perovskites: Ortho-Chromites, -Manganites and -Ferrites

1970 ◽  
Vol 24 (4) ◽  
pp. 436-445 ◽  
Author(s):  
G. V. Subba Rao ◽  
C. N. R. Rao ◽  
J. R. Ferraro
Keyword(s):  
Magnetic Properties ◽  
Rare Earth ◽  
Transition Metal ◽  
Ir Spectra ◽  
Electronic Spectra ◽  
Transition Metal Ions ◽  
Rare Earth Ions ◽  
Electronic Transitions ◽  
Rare Earth Ion ◽  
The Rare Earth

The electronic and ir spectra of rare earth perovskites of the general formula LnZO3, where Ln is the rare earth ion or yttrium and Z is Cr, Mn, or Fe, have been studied in detail. The results have been discussed in terms of crystallography, magnetic properties, covalency of Ln—O and Z—O bonds, and Goodenough's one electron energy diagrams. In all these compounds the rare earth ions do not markedly affect the electronic transitions of the transition metal ions; the 3 d electrons clearly exhibit localized behavior. Both the electronic and ir spectra of the LnZO3 perovskites are comparable to the spectra of the corresponding transition metal sesquioxides, Z2O3.

Temperature dependence of the magnetic properties of the rare-earth-transition-metal intermetallic Lu2Fe14C

1991 ◽  
Vol 96 (1-3) ◽  
pp. 219-222 ◽  
Author(s):  
Zhang Zhi-dong ◽  
X.K. Sun ◽  
Zhao Zhi-gang ◽  
Y.C. Chuang ◽  
F.R. de Boer
Keyword(s):  
Magnetic Properties ◽  
Rare Earth ◽  
Transition Metal ◽  
Temperature Dependence ◽  
The Rare Earth

Modified TiO2Structures with Enhanced Photoluminescence and Photocatalytic Activity

2021 ◽  
Vol 13 (2) ◽  
pp. 331-341
Author(s):  
Jinqi Wang ◽  
Guopeng Li ◽  
Wei Wang ◽  
Fuxia Li ◽  
Chuankai Yang ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Rare Earth ◽  
Photocatalytic Degradation ◽  
Environmental Remediation ◽  
Rare Earth Ions ◽  
Shell Structures ◽  
Rare Earth Complex ◽  
Core Shell ◽  
Rare Earth Ion ◽  
The Rare Earth

Photocatalytic degradation of pollutants has attracted much attention because it can effectively solve the problem of environmental pollution. SiO2@Eu(TTA)3phen@TiO2 core-shell structures were successfully synthesized for the first time by a solvothermal method involving ultrasound assistance which can optimize the rare earth complex dispersibility and achieve strong emission intensity. SiO2@Eu3+@TiO2 core-shell structures were also successfully synthesized by a similar method. Photocatalytic activity analysis showed that the photocatalytic activity factor not only depended on the rare earth ion content, but also related to the structure and size of the TiO2 nanoparticles. Photocatalytic activity increased first and then decreased with the quantity of rare earth ions. Photocatalytic activity was also superior for hollow structures compared to solid structure. Photocatalytic activity of SiO2@TiO2 particles increased with the particle size, until the size increased to 450 nm. Rare earth ions content as well as particle structures and sizes affected efficiency for the photocatalytic degradation of methyl orange. Outstanding photocatalytic activity provides the composite particles with improved potential to purify aquatic contaminants and to meet the demands of future environmental remediation applications.

scholarly journals Simple Preparation of LaPO4:Ce, Tb Phosphors by an Ionic-Liquid-Driven Supported Liquid Membrane System

2019 ◽  
Vol 20 (14) ◽  
pp. 3424
Author(s):  
Jianguo Li ◽  
Hongying Dong ◽  
Fan Yang ◽  
Liangcheng Sun ◽  
Zhigang Zhao ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Rare Earth ◽  
High Efficiency ◽  
Liquid Membrane ◽  
Membrane System ◽  
Rare Earth Ions ◽  
Raw Material ◽  
Supported Liquid Membrane ◽  
Rare Earth Ion ◽  
The Rare Earth

In this work, LaPO4:Ce, Tb phosphors were prepared by firing a LaPO4:Ce, Tb precipitate using an ionic-liquid-driven supported liquid membrane system. The entire system consisted of three parts: a mixed rare earth ion supply phase, a phosphate supply phase, and an ionic-liquid-driven supporting liquid membrane phase. This method showed the advantages of a high flux, high efficiency, and more controllable reaction process. The release rate of PO43− from the liquid film under different types of ionic liquid, the ratio of the rare earth ions in the precursor mixture, and the structure, morphology, and photoluminescence properties of LaPO4:Ce, Tb were investigated by inductively coupled plasma-atomic emission spectroscopy, X-ray diffraction, Raman spectra, scanning electron microscopy, and photoluminescence emission spectra methods. The results showed that a pure phase of lanthanum orthophosphate with a monoclinic structure can be formed. Due to differences in the anions in the rare earth supply phase, the prepared phosphors showed micro-spherical (when using rare earth sulfate as the raw material) and nanoscale stone-shape (when using rare earth nitrate as the raw material) morphologies. Moreover, the phosphors prepared by this method had good luminescent properties, reaching a maximum emission intensity under 277 nm excitation with a predominant green emission at 543 nm which corresponded to the 5D4-7F5 transition of Tb3+.

Local symmetry and Z-scan analysis of ZnSe/Eu3+ doped sol–gel silica hosts

2010 ◽  
Vol 88 (7) ◽  
pp. 493-500 ◽  
Author(s):  
Siby Mathew ◽  
K. V. Arun Kumar ◽  
C. Sudarsanakumar ◽  
V. P.N. Nampoori ◽  
N. V. Unnikrishnan
Keyword(s):  
Rare Earth ◽  
Sol Gel ◽  
Glass Network ◽  
Local Symmetry ◽  
Wide Distribution ◽  
Rare Earth Ions ◽  
Saturable Absorption ◽  
Rare Earth Ion ◽  
Enhanced Absorption ◽  
The Rare Earth

Vibrational state side-band spectral analysis of silica matrices, doped with ZnSe/Eu3+ ions, associated with the excitation transition 7F0→5D2 is used to analyze the local asymmetry of the rare earth ions in the glass host. The large inhomogeneous linewidth for the ZnSe co-doped samples indicates the wide distribution of the Eu3+ ions in the matrix and is related to the flexibility of the local glass network. The fluorescence spectra reveal that the intensity of the characteristic emission of europium increases considerably in the presence of ZnSe particles. This phenomenon can be explained by the energy transfer resulting from electron–hole recombination in the ZnSe to the rare earth ion. Nonlinear optical absorption of the sample is also investigated at a wavelength of 532 nm, using open aperture Z-scan technique. The sample exhibits reversible saturable absorption (RSA), which is found to depend on excitation fluence. RSA is due to the enhanced absorption resulting from the electron dynamics in nano-crystallites.

Magnetic Anisotropy in Rare-Earth - Transition Metal Intermetallic Compounds

1999 ◽  
Vol 577 ◽  
Author(s):  
Nguyen Hoang Luong ◽  
Nguyen Phu Thuy ◽  
Pham Hong Quang ◽  
Pham Duc Thang
Keyword(s):  
Rare Earth ◽  
Transition Metal ◽  
Intermetallic Compounds ◽  
Rare Earth Ions ◽  
Spin Reorientation ◽  
Hard Magnetic Materials ◽  
Crystalline Electric Field ◽  
Principal Axes ◽  
Powder Samples ◽  
The Rare Earth

ABSTRACTIn this work the rare-earth anisotropy in the rare-earth - transition metal intermetallic compounds is investigated by studying the temperature-induced spin reorientation phenomena on aligned powder samples and by analyzing the temperature dependence of the magnetization measured along different principal axes of single crystals. From such investigations the crystalline-electric-field parameters of the rare-earth ions in these compounds have been derived. The results on different hard magnetic materials of the compositions R2Fe14B, RFe11 and their substituted compounds as well as R2Co17 are summarized.

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