![Sample our Physical Sciences journals, sign in here to start your FREE access for 14 days]({"type":"image" , "src" : "/sda/110819/TOC-Subject-Sample-2021-Physical-Sciences.jpg"})
Abstract
Measurements of three principal refractive indices in ferroelectric crystals KTiOPO4, RbTiOPO4 and TlTiOPO4 were made in the temperature range from 20 K to 1100 K at three laser's wavelengths 0.44 μm, 0.63 μm and 1.15 μm. The contribution of spontaneous electro-optical effect to temperature variations of the refractive index was evaluated in RTP and TTP crystals and this allowed to find the spontaneous polarization Ps and its temperature variations. In TTP the phase transition at Tc = 851 K was found to be of the second order with the critical exponent β = 0.48 ± 0.02 for the order parameter Ps . The fluctuational contribution was found to exist up to 930 K and to vary as [(T-Tc )/Tc ]. 0.54 ± 0.02
