Peculiarities of diffuse synchrotron radiation scattering in the SBN-60 single crystal at room temperature

The study of Sr0.6Ba0.4Nb2O6 (SBN-60) crystal structure at room temperature and at the zero applied electric field has been carried out by synchrotron radiation scattering. The wavelength of incident X-rays was λ = 0.7749 Å, the Δλ/λ value was ≈ 2۰10-4. The two-dimensional distributions of diffuse and elastic intensities were obtained and analyzed in the several cross-sections: (H K 0), (H K 1/2), (H K 1), (H K 2), (H 0 L)and (H H L). As a result, it was shown the coexistence of two different types of ordering with different correlation lengths and various correlation functions: the first type is described by squared Lorentzian and the second one – by Lorentzian. The first component is characterized by the correlation lengths ξ(1) ab ≈ 10 nm and ξ(1)c ≈ 15 nm, the second one is with ξ(2)ab ≈ 3 nm and ξ(2)c ≈ 25 nm.