scholarly journals Low-T neutron powder-diffraction and synchrotron-radiation IR study of synthetic amphibole Na(NaMg)Mg5Si8O22(OH)2

2005 ◽  
Vol 90 (4) ◽  
pp. 695-700 ◽  
Author(s):  
G. Iezzi
Keyword(s):  
Synchrotron Radiation ◽  
Powder Diffraction ◽  
Neutron Powder Diffraction ◽  
Ir Study

Modulation of atomic positions in CaCu x Mn7−x O12 (x ≤ 0.1)

2009 ◽  
Vol 65 (5) ◽  
pp. 535-542 ◽  
Author(s):  
W. Sławiński ◽  
R. Przeniosło ◽  
I. Sosnowska ◽  
M. Bieringer ◽  
I. Margiolaki ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Low Temperature ◽  
Long Range ◽  
Powder Diffraction ◽  
Magnetic Moments ◽  
Magnetic Ordering ◽  
Neutron Powder Diffraction

The modulation of atomic positions in CaCu x Mn7−x O12 (x = 0 and 0.1) was studied using synchrotron radiation powder diffraction below 250 and 220 K, respectively. The copper-rich member CaCu x Mn7−x O12 (x = 0.23) does not show any modulation of the atomic positions at temperatures as low as 10 K. Using low-temperature neutron powder diffraction the modulation of the magnetic moments of Mn ions in CaCu x Mn7−x O12 (x = 0, 0.1 and 0.23) has been investigated. Long-range modulated magnetic ordering in CaCu x Mn7−x O12 (x = 0, 0.1 and 0.23) is observed below 90.4, 89.2 and 78.1 K. (0,0,q p) and (0,0,q m) are the propagation vectors describing the modulations of the atomic positions and the magnetic moments. For CaCu x Mn7−x O12 (x = 0 and 0.1) the magnetic modulation and atomic modulation lengths are related by a factor of 2 satisfying the relation (1 − q p) = 2(1 − q m).

Neutron powder diffraction study of phase separation in La2CuO4+δ

1994 ◽  
Vol 235-240 ◽  
pp. 841-842 ◽  
Author(s):  
F. Izumi ◽  
Y.-I. Kim ◽  
E. Takayama-Muromachi ◽  
T. Kamiyama
Keyword(s):  
Phase Separation ◽  
Diffraction Study ◽  
Powder Diffraction ◽  
Neutron Powder Diffraction

Neutron powder diffraction study of orthorhombic Ba 2 YCu 3 O 6.5

1987 ◽  
Vol 22 (12) ◽  
pp. 1733-1740 ◽  
Author(s):  
S. Miraglia ◽  
F. Beech ◽  
A. Santoro ◽  
D. Tran Qui ◽  
S.A. Sunshine ◽  
...  
Keyword(s):  
Diffraction Study ◽  
Powder Diffraction ◽  
Neutron Powder Diffraction

Use of Neutron Diffraction for Describing Texture of Isostatically-Pressed Molybdite Powders

2005 ◽  
Vol 105 ◽  
pp. 83-88 ◽  
Author(s):  
H. Sitepu ◽  
Heinz Günter Brokmeier
Keyword(s):  
Crystal Structure ◽  
Neutron Diffraction ◽  
Powder Diffraction ◽  
Quantitative Description ◽  
Neutron Powder Diffraction ◽  
Powder Diffraction Data ◽  
Neutron Powder Diffraction Data ◽  
Pole Figures ◽  
Diffraction Patterns ◽  
Excellent Tool

The modelling and/or describing of texture (i.e. preferred crystallographic orientation (PO)) is of critical importance in powder diffraction analysis - for structural study and phase composition. In the present study, the GSAS Rietveld refinement with generalized spherical harmonic (GSH) was used for describing isostatically-pressed molybdite powders neutron powder diffraction data collected in the ILL D1A instrument. The results showed that for texture in a single ND data of molybdite the reasonable crystal structure parameters may be obtained when applying corrections to intensities using the GSH description. Furthermore, the WIMV method was used to extract the texture description directly from a simultaneous refinement with 1368 whole neutron diffraction patterns taken from the sample held in a variety of orientations in the ILL D1B texture goniometer. The results provided a quantitative description of the texture refined simultaneously with the crystal structure. Finally, the (002) molybdite pole-figures were measured using the GKSS TEX2 texture goniometer. The results showed that neutron diffraction is an excellent tool to investigate the texture in molybdite.

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