Data for: Formation of ordered defect structures in lithium niobate crystals of different chemical composition at non-equilibrium processes of different nature
Description
Crystals LiNbO3:Cu(0.57):Gd(0.07 wt %) and LiNbO3:Mg (0.69 wt %) were treated by a laser ablation (lambda=266 nm). On their surface appeared ordered structure of defects. These pictures were taken on an optical microscope. Laser ablation of the crystal LiNbO3:Cu(0.57):Gd(0.07 wt %) had the following parameters: radiation generation frequency 10Hz, pulse duration 4 ns, laser diameter was strictly controlled in the size ~ 20 μm at 100% of a used power, this corresponded to an energy density ~ 6.1 J/cm2. Laser ablation of the crystal LiNbO3:Mg (0.69 wt %) had the following parameters: radiation generation frequency 10Hz, pulse duration 4 ns, laser diameter ~ 100 μm at 60% of a used power, this corresponded to an energy density ~ 180 J/cm2. In order to reveal the details of the relief after laser ablation the surfaces of crystals LiNbO3:Cu(0.57):Gd(0.07 wt %) and LiNbO3:Mg (0.69 wt %) were twice etched with a mixture of acids HNO3:HF=3:1, first time for 18h, second time for 24h. Strong mechanical stresses caused appearance of an ordered system of defects in the form of specially arranged cracks in the crystal LiNbO3:Zn(2 wt % in a crystal),B(0.1 wt % in a melt). Cracks apparently appeared due to a high final concentration of zinc in a crystal and the presence of a strong complexing agent (boron) in the melt. Crystals surface was carried out with image analysis system “Thixomet” including optical microscope Axio Observer.D1m by “Carl Zeiss” and program complex “Thixomet Standard” in dark and light fields.