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    Preparing large single crystalline bodies of rare earth chalcogenides
    7.
    发明授权
    Preparing large single crystalline bodies of rare earth chalcogenides 失效
    制备稀土硫属化物的大单晶体

    公开(公告)号：US3382047A

    公开(公告)日：1968-05-07

    申请号：US41809964

    申请日：1964-12-14

    Applicant: IBM

    Inventor： FREDERIC HOLTZBERG ,  METHFESSEL SIEGFRIED I

    IPC: C01B19/00 ,  C30B1/02 ,  G02F1/00

    CPC classification number: G02F1/0036 ,  C01B19/007 ,  C30B1/02 ,  C30B29/46 ,  Y10S65/15

    Abstract: Crystals of rare earth chalcogenides are prepared by compressing a rare earth chalcogenide powder, placing the resultant body of compressed powder in a crucible, sealing the crucible in a manner such as to exclude gases which react with the body, heating the body within the sealed crucible to a temperature of from 100 DEG to 300 DEG C. below the melting point of the powder for a period of from 1 to 4 hours (preferably 2 hours) and allowing the powder to cool for 1 to 4 hours (preferably 2 hours). Cooling may be prolonged by applying heat to the powder. The sealing of the crucible may be performed whilst the crucible is evacuated or in a chamber containing only gas which is inert with respect to the powder, preferably helium. The crucible may consist of Ta, W, Ir or Re and the rare earth chalcogenide may have the formula MA or M2A3 where M is La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Sc or Y and A is O, S, Se or Te. The powder may also consist of a mixture of rare earth chalcogenides. The body may be contained in the lower portion only of the crucible and the inside of the crucible may be pointed, the body of compressed powder having a complementary shape. A seed crystal may be disposed at the point of the crucible. Heating may be accomplished within a limited heating zone and the crucible and the zone may be progressively moved relative to one another to cause the crucible to leave the heating zone in a direction such that the bottom of the crucible is withdrawn first. The heating may be effected by electric induction and the heating zone may remain stationary while the crucible is moved by means of a rack and pinion.

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