Mgイオンを固溶したPbTiO_3単結晶の育成及び評価

概要

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PbTiO_3 single crystals with various quantities of added Mg^<2+> ions were grown by the flux cooling method using a platinum crucible. As-grown and poled PbTiO_3 single crystals were used for measurement of pyroelectric properties. (1) The added Mg^<2+> ions showed no significant effects on the crystal size and yield, but affected the crystal completeness. (2) The PbTiO_3 single crystals were reddish brown and highly transparent when the quantity of added MgO was in the range of 4000 to 6000 ppm. Using a microscope to observe the domain structure, it was confirmed that the crystals are composed of multidomains' consisting of 180° and 90° domains. (3) The axial ratio and the theoretical density of the crystal decreased with increasing MgO content. Based on the data of undoped crystals, the maximum decreases in the axial ratio and the theoretical density of Mg^<2+>-doped crystals were approximately 1.88% and 3.31%, respectively. (4) From the measurement of pyroelectric constants, the pyroelectric coefficient P and the figure of merit F.M. exhibited the highest values when the quantity of added MgO was 6000 ppm, reaching 2.7X10^<-8> C/cm^2・K and 0.6X10^<-10>・cmC/J, respectively.
1988-09-01