In the present invention, a crucible formed of SiC as a main component is used as a container for a SiC solution. A metal element M (M is at least one metal element selected from at least one of a first group consisting of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho and Lu, a second group consisting of Ti, V, Cr, Mn, Fe, Co, Ni and Cu and a third group consisting of Al, Ga, Ge, Sn, Pb and Zn) is added to the SiC solution and the crucible is heated to elute Si and C, which are derived from a main component SiC of the crucible, from a high-temperature surface region of the crucible in contact with the SiC solution, into the SiC solution. In this way, precipitation of a SiC polycrystal on a surface of the crucible in contact with the SiC solution is suppressed.

In the present invention, a crucible formed of SiC as a main component is used as a container for a SiC solution. The SiC crucible is heated such that, for example, an isothermal line representing a temperature distribution within the crucible draws an inverted convex shape; and Si and C, which are derived from a main component SiC of the crucible, are eluted from a high-temperature surface region of the crucible in contact with the SiC solution, into the SiC solution, thereby suppressing precipitation of a SiC polycrystal on a surface of the crucible in contact with the SiC solution. To the SiC solution of this state, a SiC seed crystal is moved down from the upper portion of the crucible closer to the SiC solution and brought into contact with the SiC solution to grow a SiC single crystal on the SiC seed crystal.

In the present invention, a crucible formed of SiC as a main component is used as a container for a SiC solution. The SiC crucible is heated such that, for example, an isothermal line representing a temperature distribution within the crucible draws an inverted convex shape; and Si and C, which are derived from a main component SiC of the crucible, are eluted from a high-temperature surface region of the crucible in contact with the SiC solution, into the SiC solution, thereby suppressing precipitation of a SiC polycrystal on a surface of the crucible in contact with the SiC solution. To the SiC solution of this state, a SiC seed crystal is moved down from the upper portion of the crucible closer to the SiC solution and brought into contact with the SiC solution to grow a SiC single crystal on the SiC seed crystal.

A single crystal composition includes an alkali halide crystal doped with a divalent element in the amount of 0.5 to 5 weight percent, the doped crystal having an optical transmission of at least 45% at at least one wavelength. An alkali halide doped with at least one of europium and ytterbium is particularly useful as a scintillator.

A single crystal composition includes an alkali halide crystal doped with a divalent element in the amount of 0.5 to 5 weight percent, the doped crystal having an optical transmission of at least 45% at at least one wavelength. An alkali halide doped with at least one of europium and ytterbium is particularly useful as a scintillator.

A system and method provides a piezoelectric stack arrangement for reduced driving voltage while maintaining a driving level for active piezoelectric materials. A stack arrangement of d.sub.36 shear mode <011>single crystals of both air X-cut and Y-cut 1:45 (20) arrangement are bonded with discrete conductive pillars to form a shear crystal stack. The bonding area between the neighboring crystal parts is minimized. The bonding pillars are positioned at less than a total surface are of the single crystal forming the stack. The stack fabrication is facilitated with a precision assembly system, where crystal parts are placed to desired locations on an assembly fixture for alignment following the preset operation steps. With the reduced clamping effect from bonding due to lower surface coverage of the discrete conductive pillars, such a piezoelectric d.sub.36 shear crystal stack exhibits a reduced driving voltage while maintaining a driving level and substantial and surprisingly improved performance.