Second-harmonic generation in Nd3＋ ：SBN crystal with needle-like ferroelectric with aperiodic domain structures is investigated. Two pairs of second harmonic （SH） waves appearing in lines are observed in unpoled ...Second-harmonic generation in Nd3＋ ：SBN crystal with needle-like ferroelectric with aperiodic domain structures is investigated. Two pairs of second harmonic （SH） waves appearing in lines are observed in unpoled Nd3＋ ：SBN crystals with aperiodic needle-like domains. A pair of SH waves emit from the exit face, whose intensities are angle-dependent. The angular dependence is corresponding to the spatial frequency spectrum of the aperiodic domain structure. Another pair of SH waves emit from both the side surfaces, which are mainly the scattered SH waves by needle-like domain walls and obey the theory of Rayleigh scattering.展开更多
The formation and evolution of the self-assembled nanodomain structures during polarization reversal have been comparatively analyzed in single crystals of various uniaxial ferroelectrics:LiNbO_(3)(LN),LiTaO_(3)(LT)an...The formation and evolution of the self-assembled nanodomain structures during polarization reversal have been comparatively analyzed in single crystals of various uniaxial ferroelectrics:LiNbO_(3)(LN),LiTaO_(3)(LT)and Sr_(x)Ba_(1-x)Nb_(2)O_(6)(SBN).Several experimental methods have been used for visualization of the micro-and nanodomain patterns.The static domain images have been obtained by optical microscopy and piezoresponse force microscopy.The Raman confocal microscopy allowed us to obtain the domain images in the bulk.The equilibrium slow switching with effective screening resulted in growth of polygon-shaped microdomains:hexagons in LN,triangles in LT and squares in SBN,which corresponds to crystal symmetry.Switching in nonequilibrium conditions(noneffective screening of depolarization field)brings to appearance of similar nanodomain structures in all studied crystals as a result of different processes:(1)formation of nanodomain ensembles,(2)discrete switching,(3)incomplete merging and(4)spontaneous backswitching.展开更多
基金National Natural Science Foundation of China under Grant No 61675101
文摘Second-harmonic generation in Nd3＋ ：SBN crystal with needle-like ferroelectric with aperiodic domain structures is investigated. Two pairs of second harmonic （SH） waves appearing in lines are observed in unpoled Nd3＋ ：SBN crystals with aperiodic needle-like domains. A pair of SH waves emit from the exit face, whose intensities are angle-dependent. The angular dependence is corresponding to the spatial frequency spectrum of the aperiodic domain structure. Another pair of SH waves emit from both the side surfaces, which are mainly the scattered SH waves by needle-like domain walls and obey the theory of Rayleigh scattering.
文摘The formation and evolution of the self-assembled nanodomain structures during polarization reversal have been comparatively analyzed in single crystals of various uniaxial ferroelectrics:LiNbO_(3)(LN),LiTaO_(3)(LT)and Sr_(x)Ba_(1-x)Nb_(2)O_(6)(SBN).Several experimental methods have been used for visualization of the micro-and nanodomain patterns.The static domain images have been obtained by optical microscopy and piezoresponse force microscopy.The Raman confocal microscopy allowed us to obtain the domain images in the bulk.The equilibrium slow switching with effective screening resulted in growth of polygon-shaped microdomains:hexagons in LN,triangles in LT and squares in SBN,which corresponds to crystal symmetry.Switching in nonequilibrium conditions(noneffective screening of depolarization field)brings to appearance of similar nanodomain structures in all studied crystals as a result of different processes:(1)formation of nanodomain ensembles,(2)discrete switching,(3)incomplete merging and(4)spontaneous backswitching.
