PURPOSE: To sufficiently execute a preheating stage without exposing a ground surface substrate to solvent vapor and to obtain a single crystal film having good quality by horizontally movably providing doors which can partition a vertical cylindrical furnace core tube right above the crucible in this furnace core tube.
CONSTITUTION: The cylindrical furnace core tube is vertically bisected to 1, 2 and a pair of the semicircular doors 3a, 3b of the diameter larger than the diameter of the furnace core tubes 1, 2 are inserted freely slidably between both from the left and the right and are made openable and closable. The doors 3 are closed and, for example, a garnet raw material and solvent are mixed in the crucible 7 within the furnace core tube 2 and are heated by heaters 10, 11, by which the raw material is solutionized 12, and thereafter, the temp. is lowered to a supercooled state. On the other hand, the disk-shaped ground surface substrate 13 held horizontally in the furnace core tube 1 is lowered and is stopped right above the doors 3. The substrate is then preheated to approximately the same temp. as the temp. of the soln. 12 by a heater 9. The PbO vapor of the solvent is generated from the melt 12 at this time but is discharged from a discharge port 17 and, therefor there is no possibility that the ground surface substrate 13 is contaminated with the PbO vapor. The doors 3 are thereafter, opened and the single crystal film of magnetic garnet is formed.
FUJINO MASARU
MIZUNO TSUGUNOBU
AOTA MITSUHIRO
SEKIJIMA KATSUNORI
TAKAGI HIROSHI
