Abstract: In a process for pulling a crystal such as Si, Ge, GaAs, InP, GaP, InAs, AlAs, CdTe, CdSe, ZnTe, HgTe, MnTe, Gd.sub.3 Ga.sub.5 O.sub.12, Bi.sub.12 SiO.sub.20 and LiNbO.sub.3 from a raw material melt within a baffle plate whose bore diameter is gradually increased upward and which is arranged in such a manner that the melt inside and outside the baffle plate is in communication with each other through the small opening part at the end thereof, the baffle plate is moved relatively to the surface of the melt so as to increase the diameter of the melt surface inside the baffle plate with the increase of the diameter of the pulled crystal at the solid-liquid interface.

Abstract: A method and apparatus for recovering the inner crucible used in a double crucible process of drawing-up a single crystal. The inner crucible is recovered by pulling up the inner crucible above the molten raw material using only a simply arranged jig which does not require reconstruction of the vessel accommodating the single crystal drawing-up system. The arrangement is such that the inner crucible is allowed to rotate during the period in which the single crystal is being grown.

Abstract: In an apparatus for the Czochralsky growth of compound single crystals wherein a single crystal growing portion is provided in a sealed vessel whose opening part is sealed by a B.sub.2 O.sub.3 melt and which contains therein an atmosphere of a volatile element of the compound, at least the inner wall the sealed vessel is made of a material having a melting point of at least 1400.degree. C., selected from Group III-V compounds and oxides of Group III or V elements. Compound single crystals such as GaAs, GaP, InAs, InP, ZnS, ZnSe and CdS obtained by the use of this apparatus are free from contamination with silicon.

Abstract: A single crystal is prepared by drawing up a single crystal by the Czochralski process and cooling it at a temperature not lower than 600.degree. C. in vacuo. In this manner a single crystal having a dislocation density of 1.5.times.10.sup.4 cm.sup.2 or less is prepared.

Abstract: A magnetic field and electric current measuring device which uses bismuth silicon oxide (Bi.sub.12 SiO.sub.20) or bismuth germanium oxide (Bi.sub.12 GeO.sub.20) as a Faraday cell, and which is so adapted that polarized light which enters the cell is passed back and forth through the cell along the optic axis thereof to cancel any change in optical rotatory power ascribable to a variation in temperature. A magnetic field applied in the direction of the optic axis of the Faraday cell is measured based on the angle of rotation of the polarization plane of the polarized light. The surface of the Faraday cell may be coated with a transparent and electrically conductive thin film to eliminate the effects of external electric fields.

Abstract: An apparatus for producing a single crystal according to the CZ method, which comprisesa closed container consisting of upper and lower halves and having a shaft for pulling up the single crystal, at least a part of which contacting with said vapor of the elements is made of a material containing an element of the same group of the periodic table as that of component elements of the single crystal, a gap between said shaft and the container and an opening between said upper and lower halves of the container being sealed with a sealing material,at least one reservoir positioned in the container for supplying vapor of a volatile component element of the single crystal, anda heating means provided around the container; wherein a hot zone of the apparatus including the container is made of a material which has an X-ray absorption coefficient not larger than 5 cm.sup.2 /g, and said material of the hot zone has such thickness that X-ray transmittance through the whole hot zone is 10.sup.

Abstract: A voltage and electric field measuring device is disclosed. The device uses light, including a polarizer, an electro-optic crystal consisting of a material having an optical rotatory power, and an analyzer arranged in the stated order in the direction of advancement of applied light, with a quarter-wave plate being disposed between the polarizer and crystal or between the crystal and analyzer. The angle of orientation .psi. of the analyzer, relative to the optical axis of the crystal, is set to the product of .theta. and l, where .theta. represents the optical rotatory power, with respect to the applied light, of the crystal near a point at the center of a range of varying temperatures at the installation environment, and l represents the thickness of the crystal measured in the direction of advancement of light. The specified relation between .psi. and .theta..multidot.l maximizes the temperature stability of the device.

Abstract: A process for preparing a single crystal comprising drawing up a single crystal by the Czochralski process and cooling it at a temperature not lower than 600.degree. C. at a reduced pressure or in vacuo, by which a single crystal having a dislocation density of 1.5.times.10.sup.4 cm.sup.2 or less is prepared.

Abstract: A process for manufacturing boron-doped GaAs single crystals which comprises preparing a mixture of boron, gallium and arsenic covered by a liquid B.sub.2 O.sub.3 encapsulant, melting the mixture, pulling up boron-doped GaAs crystals from the mixture melts in accordance with the LEC method, crushing those crystals into small pieces after removing the seed end therefrom, remelting those pieces in the presence of B.sub.2 O.sub.3, and pulling up single crystals from the mixture melts in accordance with the LEC method.