The congruently melting composition of Lithium Niobate(LN) is 48.6mol% Li 2O,rather than stoichiometric 50mol%Li 2O.By means of conventional Czochralski(CZ) method,it is easy to grow the congruent LN crystal with high...The congruently melting composition of Lithium Niobate(LN) is 48.6mol% Li 2O,rather than stoichiometric 50mol%Li 2O.By means of conventional Czochralski(CZ) method,it is easy to grow the congruent LN crystal with high quality,but difficult to grow the stoichiometric LN crystal with homogeneous composition. In contrast to CZ method,Melting Zone(MZ) method makes use of the segregation of solute,and is likely to grow homogeneous crystal.By MZ method,we have grown near stoichiometric LN crystal (Li%mol=49.5%) from stoichiometric LN raw material. The difference between the raw material and the crystal is due to the volatilization loss of Lithium at the growing temperature.With 50.5mol%Li 2O LN raw material,stoichiometric LN crystal could be grown. Li rich LN solvent zone preplaced in the melting zone makes the crystal much more homogeneous than that without the solvent zone.The preplaced Li rich zone heightens the starting [Li] concentration of the liquid phase,so that the initial [Li] concentration of LN crystal is close to the stable value,and the process of stabilization is shortened.展开更多
The growth of crystals of the high T c oxide superconductors has been hampe red by the complexities of the materials and their phase diagrams.The most common crys tal growth technique adopted for these oxides is the ...The growth of crystals of the high T c oxide superconductors has been hampe red by the complexities of the materials and their phase diagrams.The most common crys tal growth technique adopted for these oxides is the “flux”method,where the st arting materials are solved in a melt,which is usually formed by excess CuO and BaO or a KCl/NaCl mixture.The crystals are produced by slow cooling of the heate d solvent.This method,however,suffers from several disadvantages: (1) the crystals are contaminated with the crucible material, (2) the crystals are difficult to remove from the crucible, (3) the crystals contain flux inclusions.展开更多
文摘The congruently melting composition of Lithium Niobate(LN) is 48.6mol% Li 2O,rather than stoichiometric 50mol%Li 2O.By means of conventional Czochralski(CZ) method,it is easy to grow the congruent LN crystal with high quality,but difficult to grow the stoichiometric LN crystal with homogeneous composition. In contrast to CZ method,Melting Zone(MZ) method makes use of the segregation of solute,and is likely to grow homogeneous crystal.By MZ method,we have grown near stoichiometric LN crystal (Li%mol=49.5%) from stoichiometric LN raw material. The difference between the raw material and the crystal is due to the volatilization loss of Lithium at the growing temperature.With 50.5mol%Li 2O LN raw material,stoichiometric LN crystal could be grown. Li rich LN solvent zone preplaced in the melting zone makes the crystal much more homogeneous than that without the solvent zone.The preplaced Li rich zone heightens the starting [Li] concentration of the liquid phase,so that the initial [Li] concentration of LN crystal is close to the stable value,and the process of stabilization is shortened.
文摘The growth of crystals of the high T c oxide superconductors has been hampe red by the complexities of the materials and their phase diagrams.The most common crys tal growth technique adopted for these oxides is the “flux”method,where the st arting materials are solved in a melt,which is usually formed by excess CuO and BaO or a KCl/NaCl mixture.The crystals are produced by slow cooling of the heate d solvent.This method,however,suffers from several disadvantages: (1) the crystals are contaminated with the crucible material, (2) the crystals are difficult to remove from the crucible, (3) the crystals contain flux inclusions.
