| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a method of making a single crystal have single domain for making high quality single domain ferroelectric crystals having aligned direction of spontaneous polarization of ferroelectric within the crystals, in producing potassium niobate KNbO3 single crystals. SOLUTION: In the method of making the potassium niobate single crystals have single domains by forming positive and negative electrodes 16, 17 on the opposed surfaces of a potassium niobate single crystal 15 having a multi domain structure, and applying an electric field between the electrodes, the treatment for making single domain is executed by two steps comprising a first step of the treatment for making single domain is performed by applying an electric field between the electrodes at a temperature below structural phase transition temperature from the tetragonal system to the orthorhombic system and above 170 deg.C, and a second step of the treatment by applying an electric field higher than that of the first treatment between the electrodes at a temperature below 170 deg.C. Thus, transparent single crystals having aligned direction of spontaneous polarization over whole the crystals are obtained.</p> |
