Abstract: A buffer layer having crystal orientation In a (111) face is formed on a semiconductor single-crystal (100) substrate and a ferroelectric thin film having crystal orientation in a (111) or (0001) face is then formed over the buffer layer. The buffer layer is preferably formed of MgO at a temperature ranging from 20.degree. to 600.degree. C. and at a rate ranging from 0.5 to 50 .ANG./sec. The thus formed ferroelectric thin film has its axes of polarization aligned in one direction. Using the oriented ferroelectric thin-film device, highly functional nonvolatile memories, capacitors or optical modulators can be fabricated on semiconductor substrates.

Abstract: A method for providing an nonlinear, frequency converting optical QPM waveguide device by growing a first ferroelectric oxide film or layer on a second ferroelectric layer or medium wherein, in first and second embodiments, respectively, the second layer is initially provided with a periodic nonlinear coefficient pattern or a periodic pattern comprising a seed layer. During the growth of the first layer, the periodic pattern formed in the second layer, is replicated, transformed or induced into the first layer resulting in a plurality of substantially rectangular prismatic-shaped domains in the first layer having the periodic nonlinear coefficient pattern status based upon the periodic patterning of the second layer.

Abstract: A film made of lithium niobate-lithium tantalate solid solution may be formed on a single crystal substrate having a composition of LiNb.sub.1-z Ta.sub.z O.sub.3 (0.ltoreq.z<0.8) by the liquid phase epitaxial process. The substrate is contacted with supercooled liquid phase of a melt to produce the film thereon. The melt consists mainly of Li.sub.2 O.sub.3, Nb.sub.2 O.sub.5, Ta.sub.2 O.sub.5 and a flux. A composition of the liquid phase is within a region encompassed by a straight line K linking a point A (95, 5, 0) and a point B (95, 2, 3), a straight line G linking the point A (95, 5, 0) and a point C (60, 40, 0), a straight line H linking the point C (60, 40, 0) and a point D (60, 0, 40), a straight line J linking the point B (95, 2, 3) and a point E (0, 40, 60) and a curved line I defining a composition whose saturation temperature is not more than 1200.degree. C. Each line is shown in a triangular diagram of a pseudo-ternary system of LiNbO.sub.3 -LiTaO.sub.3 --a melting medium.

Abstract: A process is disclosed for producing a film of an oxide type single crystal on a substrate of such an oxide type single crystal by epitaxially growing the oxide type single crystal on the substrate through contacting the substrate onto a melt in an overcooled state. The substrate of the oxide type single crystal is contacted with the melt held in a first furnace, and the substrate of the oxide type single crystal is held inside a second furnace separated from said first furnace, and the temperature of the substrate is adjusted in the second furnace. An oxide type single crystal film-producing apparatus is also disclosed.

Abstract: The invention provides a method of manufacturing stoichiometric potassium-lithium niobate crystals. Such crystals exhibit a high degree of double refraction and can suitably be used to double the frequency of a light wave with noncritical phase matching. By virtue of the temperature dependence of the nonlinear optical properties and the possibility of doubling the frequency at room temperature and at wavelengths from 800 to 850 nm the material according to the invention is very suitable for use in cooperation with semiconductor lasers.

Abstract: A single crystal of a compound comprises a single crystal of a compound at least part of components is of the above mentioned material decomposed at a temperature around the melting point, having a volume of 5 cc or more, and deviation of respective elements in a composition of the single crystal from the stoichiometric composition is within the range of .+-.5%.

Abstract: A process for producing optoelectric articles, in which an optoelectric single crystal film is formed on an optoelectric single crystal substrate, is disclosed. The optoelectric single crystal substrate is exposed to a liquid phase in a supercooling state of a melt including a solute and a melting medium, and the optoelectric single crystal film is formed by a liquid phase epitaxial process. In this case, a viscosity of the liquid phase is set to 75%.about.95% preferably 75%.about.90% with respect to a viscosity at which a degree of supercooling of the liquid phase is zero.

Abstract: An orientative ferroelectric thin film has such a structure that an epitaxial or orientative buffer layer having a double layer structure constituted by two layers is formed on a semiconductor single crystal (100) substrate, and an epitaxial or orientative perovskite ABO.sub.3 type ferroelectric thin film is further formed on the buffer layer. The epitaxial or orientative buffer layer has a structure in which a perovskite ABO.sub.3 type thin film is formed on an MgO thin film. Also, an orientative ferroelectric thin film has such a structure that an opitaxial MgO buffer layer is formed on a single crystal Si (100) substrate, and an epitaxial or orientative perovskite ABO.sub.3 type ferroelectric thin film is formed on the buffer layer.

Abstract: There has been provided by the present invention a process for producing a single crystal of potassium niobate which comprises disposing a positive electrode directly or via a semi-insulating substance layer on one c-plane of a single crystal of potassium niobate and also a negative electrode via a semi-insulating substance layer on the other c-plane of the single crystal of potassium niobate, said positive and negative electrodes being disposed in mutually facing relationship, and applying voltage between the positive and negative electrodes so as to pole (convert to the single-domain state) the single crystal of potassium niobate, and which enables to pole the entire region of the single crystal of potassium niobate without quality deterioration.

Abstract: A multilayer structure has an a nonlinear optical film epitaxially grown on an underlying buffer layer of substantially lower refractive index. The buffer layer itself is epitaxially grown on a single crystal substrate with an intermediate epitaxial electrode.

Abstract: The invention provides a method of manufacturing potassium-lithium-niobate crystals having a composition which corresponds to the formula(K.sub.2 O).sub.0.3 (Li.sub.2 O).sub.0.2+a (Nb.sub.2 O.sub.5).sub.0.5+bwhere-0.01<a<0.01-0.005<b<0.005from a melt comprising potassium, lithium and niobium compounds. By adding a small quantity of vanadium, preferably in the form of V.sub.2 O.sub.5, considerably larger crystals are obtained. In addition, the homogeneity of these crystals is much better than that of the crystals obtained by the method according to the prior art.

Abstract: A new compositional relationship in the starting charge of a crystal growth station (FIG. 1 ) provides homogeneous monocrystalline lithium niobate. A new measurement system (FIG. 2 ) provides Curie point values of significantly greater accuracy then that of conventional measurements. Careful control of the starting charge composition for crystal growth and effective utilization of the measurement system enable the determination of the compositional range of starting charges for producing congruent crystalline production. The composition corresponds to a mol percentage of 48.35.+-..01 to 48.40.+-..01 of Li.sub.2 O and the remainder Nb2.sub.O 5 for producing homogeneous crystal whose solidification fraction of the molten charge exceeds that which was heretofore achievable.