2002 年 29 巻 2 号 p. 11-
RNbO_4 (R: Rare-earth) crystals have ferroelastic properties. Hysteresis loop in stress-strain curve was reported on NdNbO_4 Luminescent properties were also reported on Ce or Pr doped YNbO_4 and YTaO_4. RNbO_4 single crystal were grown by Czochralski method and flux method. In this work. RNb04 (R: Gd, Dy, La and Y) single crystals are grown by Floating zone method, and are investigated their growth conditions.