Crystal Growth and Magnetic Susceptibilities of Some Rare-Earth Sodium Molybdenum Scheelites

The composition range for growing tetragonal scheelite-type single crystals, was investigated and located on the ternary diagram Gd2O3–MoO3–Na2O. Single crystals, the largest one weighing more than 1.2 g, and having a composition of R0.5Na0.5MoO4, with R=Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, and Yb, were grown by slowly cooling the ternary melts from 1000°C with rates between 1.1°–3.2°C/h. The crystals were leached out of the flux by boiling them with NH4OH. The various colored transparent pyramidal crystals have their tetragonal ``c'' axis perpendicular to the pyramidal base. The unit cell dimensions of the individual crystals are given. The magnetic susceptibilities of the scheelites of Gd and Dy are reported between 3° and 300°K. Dy or Gd scheelite did not show an ordinary ordering temperature above 1.8°K.