SINGLE CRYSTAL OF SILVER PYROPHOSPHATE AND ITS PRODUCTION

摘要

PURPOSE:To produce a transparent single crystal of silver pyrophosphate used for an optical recording material or the like which permits recording and erasing efficiently without generating any crack or the like, by pulling a single crystal from the melt of silver pyrophosphate contained in a vessel. CONSTITUTION:A raw material for growing a single crystal of silver pyrophosphate (Ag4P2O7) is made by a reaction of Ag2O and NH4H2PO4 at 400 deg.C and said raw material is fused by melting in air in a platinum crucible. A platinum wire in place ofa seed is pulled up from the melt and a single crystal having a prescribed orientation is drawn out from the resulted crystal. With said single crystal as a seed crystal, the crystal is pulled, whereby the single crystal of silver pyrophosphate is grown. Characteristics of the single crystal of pyrophosphate are; approximately 9 dielectric constant of the axis (a) at a room temp.; approximately 11 dielectric constant of the axis (c); approximately 13nOMEGAcm<-1> electric conductivity of the axis (a) at the same room temp.; approximately 2nOMEGAcm<-1> electric conductivity of the axis (c); approximately 1.829 refractive index for a normal ray of 550nm wavelength; and approximately 1.806 refractive index for the abnormal ray of the same wavelength.