Ionic Distribution in Rare Earth Ion-Doped Na+ β"- Alumina

1996 ◽  
Vol 453 ◽  
Author(s):  
Yuhu Wang ◽  
Alastair N. Cormack
Keyword(s):  
Rare Earth ◽  
Excellent Agreement ◽  
Atomistic Simulation ◽  
Local Symmetry ◽  
Previous Estimate ◽  
Rare Earth Ion ◽  
Oxygen Ions ◽  
Ionic Distribution ◽  
Conduction Plane

AbstractStructure of β"-alumina has been studied through atomistic simulation. Distribution of Mg2+ in the spinel blocks, Na+ as well as Nd3+ in the conduction planes have been calculated and compared with the structure models derived experimentally. Mg2+ ions, as the stabilizer of β"-alumina structure, prefer to occupy the tetrahedral Al(2) sites in the spinel block. Two configurations for Mg2+ distribution are proposed. Due to the presence of Mg2+, oxygen ions in or adjacent to the conduction plane, O(5), O(4) and O(3), are slightly displaced from their original sites, leading to the removal of the local symmetry at the mO site. Strongly affected by the Mg2+ distribution, Nd3+ions, originally introduced into the BR site in the conduction plane, are found to move towards the distorted mid-oxygen sites, which is in excellent agreement with the previous estimate from spectroscopie study.

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.

scholarly journals Structure, Luminescence, and Magnetic Properties of Crystalline Manganese Tungstate Doped with Rare Earth Ion

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3717
Author(s):  
Jae-Young Jung ◽  
Soung-Soo Yi ◽  
Dong-Hyun Hwang ◽  
Chang-Sik Son
Keyword(s):  
Magnetic Field ◽  
Rare Earth ◽  
Sintering Temperature ◽  
Luminescent Properties ◽  
Concentration Quenching ◽  
Rare Earth Ions ◽  
Precipitation Method ◽  
Rare Earth Ion ◽  
Co Precipitation ◽  
Quenching Phenomenon

The precursor prepared by co-precipitation method was sintered at various temperatures to synthesize crystalline manganese tungstate (MnWO4). Sintered MnWO4 showed the best crystallinity at a sintering temperature of 800 °C. Rare earth ion (Dysprosium; Dy3+) was added when preparing the precursor to enhance the magnetic and luminescent properties of crystalline MnWO4 based on these sintering temperature conditions. As the amount of rare earth ions was changed, the magnetic and luminescent characteristics were enhanced; however, after 0.1 mol.%, the luminescent characteristics decreased due to the concentration quenching phenomenon. In addition, a composite was prepared by mixing MnWO4 powder, with enhanced magnetism and luminescence properties due to the addition of dysprosium, with epoxy. To one of the two prepared composites a magnetic field was applied to induce alignment of the MnWO4 particles. Aligned particles showed stronger luminescence than the composite sample prepared with unsorted particles. As a result of this, it was suggested that it can be used as phosphor and a photosensitizer by utilizing the magnetic and luminescent properties of the synthesized MnWO4 powder with the addition of rare earth ions.

scholarly journals Conduction-band states and the 5d-4f laser transition of rare-earth ion dopants

1997 ◽  
Author(s):  
Stephen A. Payne ◽  
Christopher D. Marshall ◽  
Andy J. Bayramian ◽  
Janice K. Lawson
Keyword(s):  
Rare Earth ◽  
Conduction Band ◽  
Rare Earth Ion ◽  
Laser Transition

Photon echoes in an amplifying rare-earth ion-doped crystal

2006 ◽  
Author(s):  
V. Crozatier ◽  
G. Gorju ◽  
F. Bretenaker ◽  
J.-L. Le Gouet ◽  
I. Lorgere ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Ion ◽  
Photon Echoes

Rare-earth-ion-size control on magnetic irreversibility field in CuBa2RECu2O7−δ

2001 ◽  
Vol 357-360 ◽  
pp. 230-233 ◽  
Author(s):  
Yukiko Yasukawa ◽  
Takayuki Nakane ◽  
Maarit Karppinen ◽  
Hisao Yamauchi
Keyword(s):  
Rare Earth ◽  
Size Control ◽  
Irreversibility Field ◽  
Rare Earth Ion ◽  
Magnetic Irreversibility ◽  
Ion Size

Internal Friction Study of the Rare Earth Ion Substituted Fast Oxide-Ion Conductors (La1-ΧreΧ)2Mo2O9 (Re=Nd, Gd)

2012 ◽  
Vol 184 ◽  
pp. 110-115
Author(s):  
X.P. Wang ◽  
J. Hu ◽  
Zhong Zhuang ◽  
Tao Zhang ◽  
Qian Feng Fang
Keyword(s):  
Phase Transition ◽  
Rare Earth ◽  
Internal Friction ◽  
Diffusion Processes ◽  
Rare Earth Ion ◽  
Disorder Transition ◽  
Oxide Ion Conductors ◽  
Oxide Ion ◽  
The Rare Earth ◽  
Ion Conductors

The relaxation and phase transition behaviors of rare-earth ion substituted fast oxide-ion conductors (La1-xRex)2Mo2O9 (Re=Nd, Gd) were investigated by internal friction (IF) measurement in the temperature range 300 K - 950 K. Three different IF peaks (labeled as PL, PH, and PG, respectively) were observed in the rare-earth ion doped La2Mo2O9 samples. Peak PL corresponds to short diffusion processes of oxygen ions among different oxygen vacancy sites. Peak PH is associated with the static/dynamic disorder transition in oxygen ion distribution. Peak PG is a newly discovered peak embodying phase transition-like characteristics and is suggested to be related to order-disorder transition associated with the rearrangement of La/ Re sub-lattice.

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