The Structure of C-type Gd2O3. A Powder Neutron Diffraction Study using Enriched 160Gd

The structure of the cubic C-type phase of Gd2O3 has been refined using high-resolution powder neutron diffraction data. The sample was enriched in 160Gd to avoid the high neutron absorption of naturally occurring Gd. The refined structure is in excellent agreement with that estimated using perturbed angular correlation spectroscopy.

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Neutron diffraction study of φ-Bi8Pb5O17: structure refinement and analysis of cationic ordering

Acta Crystallographica Section B Structural Science ◽

10.1107/s0108768101001628 ◽

2001 ◽

Vol 57 (3) ◽

pp. 237-243 ◽

Cited By ~ 3

Author(s):

Lara Righi ◽

Gianluca Calestani ◽

Mauro Gemmi ◽

Andrea Migliori ◽

Marco Bettinelli

Keyword(s):

Phase Diagram ◽

Neutron Diffraction ◽

Rietveld Method ◽

Structure Refinement ◽

Neutron Diffraction Study ◽

Distribution Analysis ◽

X Ray Diffraction ◽

X Ray ◽

Powder Neutron Diffraction ◽

Powder Neutron Diffraction Data

The triclinic crystal structure of the φ phase in the structure of the Bi2O3–PbO phase diagram has been recently solved by the synergetic use of electron and X-ray diffraction on a polycrystalline Bi8Pb5O17 sample. In the present work the problem is re-examined on the basis of powder neutron diffraction data: the structure has been confirmed and refined by the Rietveld method. The increased accuracy of the O-atom positions allowed the study of the cationic ordering in this structure by means of bond-valence calculations and charge distribution analysis. The results, confirmed by the refinement of the site occupancies, indicate that the structure is ordered to a large extent, with Bi and Pb atoms occupying preferentially different lattice sites. In this frame, the φ phase being the most ordered one in the considered region of the Bi2O3–PbO phase diagram, it should represent the thermodynamically stable low-temperature polymorph.

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ChemInform Abstract: CRYSTAL STRUCTURES OF MIXED-VALENCY AND MIXED-METAL SALTS A2MIII0.5SBV0.5X6 (A = RB, CS; M = SB, BI, IN, TL, FE, RH; X = CL, BR). A POWDER NEUTRON DIFFRACTION STUDY

Chemischer Informationsdienst ◽

10.1002/chin.198526003 ◽

1985 ◽

Vol 16 (26) ◽

Author(s):

K. PRASSIDES ◽

P. DAY ◽

A. K. CHEETHAM

Keyword(s):

Neutron Diffraction ◽

Diffraction Study ◽

Crystal Structures ◽

Neutron Diffraction Study ◽

Metal Salts ◽

Mixed Valency ◽

Mixed Metal ◽

Powder Neutron Diffraction

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Defects in CdS: In detected by perturbed angular correlation spectroscopy (PAC)

Applied Surface Science ◽

10.1016/0169-4332(91)90156-e ◽

1991 ◽

Vol 50 (1-4) ◽

pp. 159-164 ◽

Cited By ~ 12

Author(s):

R. Magerle ◽

M. Deicher ◽

U. Desnica ◽

R. Keller ◽

W. Pfeiffer ◽

...

Keyword(s):

Angular Correlation ◽

Perturbed Angular Correlation ◽

Correlation Spectroscopy ◽

Perturbed Angular Correlation Spectroscopy

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Comparison of Jump Frequencies of 111In/Cd Tracer Atoms in Sn3R and In3R Phases Having the L12 Structure (R = Rare-Earth)

Defect and Diffusion Forum ◽

10.4028/www.scientific.net/ddf.311.159 ◽

2011 ◽

Vol 311 ◽

pp. 159-166 ◽

Cited By ~ 10

Author(s):

Megan Lockwood Harberts ◽

Benjamin Norman ◽

Randal Newhouse ◽

Gary S. Collins

Keyword(s):

Rare Earth ◽

Perturbed Angular Correlation ◽

Diffusion Mechanism ◽

Correlation Spectroscopy ◽

Perturbed Angular Correlation Spectroscopy ◽

Dominant Mechanism ◽

Boundary Composition ◽

Light Lanthanide ◽

Diffusion Mechanisms ◽

Jump Frequencies

Measurements were made of jump frequencies of 111In/Cd tracer atoms on the Sn-sublattice in rare-earth tri-stannides having the L12 crystal structure via perturbed angular correlation spectroscopy (PAC). Phases studied were Sn3R (R= La, Ce, Pr, Nd, Sm and Gd). Earlier measurements on isostructural rare-earth tri-indides showed that the dominant diffusion mechanism changed along that series [4]. The dominant mechanism was determined by comparing jump frequencies measured at opposing phase boundary compositions (that is, more In-rich and more In-poor). Jump frequencies were observed to be greater at the In-rich boundary composition in light lanthanide indides and greater at the In-poor boundary composition in heavy-lanthanide indides. These observations were attributed to predominance of diffusion via rare-earth vacancies in the former case and indium vacancies in the latter. Contrary to results for the indides, jump frequencies found in the present work are greater for the Sn-poor boundary compositions of the stannides, signaling that diffusive jumps are controlled by Sn-vacancies. Possible origins of these differences in diffusion mechanisms are discussed.

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