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A neutron total scattering study of local coordination in KTiOPO4 from room temperature to 900 degrees C

Stefan T. Norberg (Institutionen för kemi- och bioteknik, Oorganisk miljökemi) ; P. A. Thomas ; M. G. Tucker
Journal of Physics-Condensed Matter (0953-8984). Vol. 23 (2011), 17,
[Artikel, refereegranskad vetenskaplig]

Neutron total (Bragg plus diffuse) scattering data have been analysed by means of bond valence constrained reverse Monte Carlo modelling, using RMC Profile software, in order to simultaneously probe the natures of the short- and long-range structural correlations in potassium titanyl phosphate, KTiOPO4 (KTP). The diffraction data were collected at room temperature, 300, 500, 700 and 900 degrees C, and the resulting partial radial distribution functions, g(jk)(r), were thoroughly investigated in order to obtain information about the structural aspects that cause reduced second harmonic generation (SHG) with increasing temperature in KTP. The -TiO6-PO4- lattice shows very little rigid unit motion up to 900 degrees C and the PO4 tetrahedra were likewise unchanged. However, subtle changes regarding oxygen disordering around the TiO6 octahedra, i.e. the number of short titanyl bonds, and K+ cation displacement along the c axis are carefully mapped out. The latter has a direct detrimental effect on the SHG response, whilst the anisotropic Ti-O bond distribution seems to be a prerequisite for the SHG effect.

Nyckelord: nonlinear-optical material, ferroelectric phase-transition, potassium, titanyl phosphate, range 293-973 k, alkaline displacements, ktp, isostructures, crystal-structure, electron-density, high-resolution, doped ktp



Denna post skapades 2011-05-12. Senast ändrad 2011-05-16.
CPL Pubid: 140605

 

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Institutioner (Chalmers)

Institutionen för kemi- och bioteknik, Oorganisk miljökemi (2005-2014)

Ämnesområden

Oorganisk kemi

Chalmers infrastruktur