Abstract: Superconducting Ba--Y--Cu--O ceramic thin film is epitaxially deposited on a crystal substrate of LaAlO.sub.3, LaGaO.sub.3, PrGaO.sub.3 and NdGaO.sub.3.

Abstract: A broadly wavelength-tunable laser is provided which comprises as the laser medium a single crystal of MBO.sub.3 :Cr.sup.3+, where M is selected from the group of Sc, In and Lu. The laser may be operated over a broad temperature range from cryogenic temperatures to elevated temperatures. Emission is in a spectral range from red to infrared, and the laser is useful in the fields of defense, communications, isotope separation, photochemistry, etc.

Abstract: A large single crystal of metal orthophosphate is grown from a plurality of seed crystals by first mounting the seed crystals with one planar surface of each seed crystal substantially in contact with a planar surface of an adjoining seed crystal and a second planar surface substantially parallel to a second planar surface of the adjoining seed crystal. By known methods, the seeds are then grown into a large single crystal in an acid medium at elevated temperatures. The process is particularly useful for growing large crystals of berlinite, which can then be cut into wafers useful in surface acoustic wave devices.

Abstract: Large single crystals of berlinite are grown onto seed crystals by maintaining the crystals at a fixed elevated temperature in a pressure vessel containing a nutrient of coarse berlinite crystalline powder, held at a fixed lower temperature, and concentrated phosphoric acid. Because berlinite shows retrograde solubility, the nutrient goes into solution, and berlinite deposits on the higher-temperature growing crystal. The vessel is rocked to promote motion of saturated solution to the crystal and depleted solution to the nutrient. Large single crystals of alpha-gallium orthophosphate may be grown using the same apparatus and a similar process. The resultant crystals may be cut into wafers useful in surface acoustic wave devices.

Abstract: Berlinite crystalline powder of uniform particle size and high purity is prepared by repeated thermal cycling to react a mixture of aluminum hydroxide or aluminum oxide and an excess of concentrated phosphoric acid in a sealed pressure vessel. The vessel is preferably held in a horizontal orientation and rotated about a longitudinal axis during the reaction. The product powder is useful in growing large single crystals that have surface acoustic wave applications. Crystalline powder of alpha-gallium orthophosphate may be prepared using the same apparatus and a similar procedure.

Abstract: A piezoelectric wafer of single crystal berlinite, having a surface defined by an X-axis boule cut at an angle in the range from about 94.degree.-104.degree., provides an improved substrate for a surface acoustic wave device. These cut angles are relatively easy to fabricate, provide excellent temperature compensation in a range from -55.degree. C. to 125.degree. C., and have high piezoelectric coupling coefficient.

Abstract: A piezoelectric wafer of single crystal berlinite, having a surface defined by an X-axis boule cut at about 85.degree., provides a improved substrate for a surface acoustic wave device. The 85.degree. cut angle is relatively easy to fabricate, provides excellent temperature compensation in a range form 20.degree. C. to 100.degree. C., and has high piezoelectric coupling coefficient.

Abstract: Large single crystals of berlinite are grown onto seed crystals by maintaining the crystals at a fixed elevated temperature in a pressure vessel containing a nutrient of coarse berlinite crystalline powder, held at a fixed lower temperature, and a mixture of hydrochloric and phosphoric acids. Because berlinite shows retrograde solubility in the acid mixture, the nutrient goes into solution, and berlinite deposits on the higher-temperature growing crystal. Large single crystals of alpha-gallium orthophosphate may be grown using the same apparatus and a similar process. The resultant crystals may be cut into wafers useful in surface acoustic wave devices.

Abstract: Large single crystals of berlinite are grown onto seed crystals by maintaining the crystals at a fixed elevated temperatutre in a pressure vessel containing a nutrient of coarse berlinite crystalline powder, held at a fixed lower temperature, and concentrated phosphoric acid. Because berlinite shows retrograde solubility, the nutrient goes into solution, and berlinite deposits on the higher-temperature growing crystal. The vessel is rocked to promote motion of saturated solution to the crystal and depleted solution to the nutrient. Large single crystals of alpha-gallium orthophoshate may be grown using the same apparatus and a similar process. The resultant crystals may be cut into wafers useful in surface acoustic wave devices.

Abstract: Berlinite crystalline powder of uniform particle size and high purity is prepared by repeated thermal cycling to react a mixture of aluminum hydroxide or aluminum oxide and an excess of concentrated phosphoric acid in a sealed pressure vessel. The vessel is preferably held in a horizontal orientation and rotated about a longitudinal axis during the reaction. The product powder is useful in growing large single crystals that have surface acoustic wave applications. Crystalline powder of alpha-gallium orthophosphate may be prepared using the same apparatus and a similar procedure.