MRIA - A Program for a Full Profile Analysis of Powder Neutron-Diffraction Time-of-Flight (Direct and Fourier) Spectra

1991 ◽  
Vol 79-82 ◽  
pp. 283-288
Author(s):  
V.B. Zlokazov ◽  
V.V. Chernyshev
Keyword(s):  
Neutron Diffraction ◽  
Profile Analysis ◽  
Time Of Flight ◽  
Powder Neutron Diffraction ◽  
Full Profile ◽  
Fourier Spectra

The structures of some titanium-niobium oxides by powder neutron diffraction

1974 ◽  
Vol 338 (1614) ◽  
pp. 311-326 ◽  
Keyword(s):  
Neutron Diffraction ◽  
Profile Analysis ◽  
Detailed Examination ◽  
Ionic Model ◽  
Space Group ◽  
Cell Parameters ◽  
Powder Neutron Diffraction ◽  
Crystallographic Shear ◽  
Final Profile ◽  
Block Structures

The structures of TiNb 2 O 7 and ortho - Ti 2 Nb 10 O 29 have been examined at 4.2 K by total profile analysis of powder neutron diffraction data. The space group of TiNb 2 O 7 is A2/m and the cell parameters are a = 11.890(5), b = 3.804(2), c = 20.373(9) Å, ‡ β = 120.199 (3) deg. The final profile residual was 9.47%. The space group of ortho-Ti 2 Nb 10 O 29 is Amma and the cell parameters are a = 28.305(12), b = 3.780(2), c = 20.352(9) Å. A final profile residual of 10.62% was obtained. Substantial ordering of the cations among the different metal sites in these block structures was found, with titanium occupancy numbers varying from 14.0 to 64.5% for TiNb 2 O 7 and from 4.5 to 40.0% in ortho-Ti 2 Nb 10 O 29 . The values are consistent with site potentials obtained on an ionic model. The oxygen positions were determined with greater precision than in previous studies of block structures, affording a detailed examination of the dis­tortions around the crystallographic shear planes.

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