Study of the domain structure of ferroelectric crystals TGS with a periodic distribution of the impurity
A complex research of the features of the triglycine sulfate crystals domain structure with the periodic distribution of the chromium ions Cr <sup>+3</sup>impurity TGS-TGS+Cr on the optical (method NLC) and the micro level (the domain structure according to the piezoelectric response data of the AFM). The results are compared with domain structure of TGS+Cr with a uniform distribution of the impurities in bulk. The domain configurations on the border of the growth layers with different impurity distribution was investigated by AFM mode piezoelectric response. It is found that periodic impurity layers are formed not over the whole crystal volume of TGS-TGS+Cr, but only in certain areas, in which the polarization vector has non-zero component at a direction normal to the growth faces. Static unipolarity of domain walls in areas with the introduction of chromium and without impurities was defined. It is shown that for almost the same unipolarity density of the domain walls in chromium-doped layers is 2.3 times higher than in the layers without impurities. It was concluded that the impurity crystals with layered structure have a spatially inhomogeneous conductivity.