JPS6177694A - Preparation of single crystal having uniform composition - Google Patents

Abstract

PURPOSE:To obtain a single crystal having uniform compsn. over its whole length of crystal growth by replenishing continuously raw materials for the solid crystal having different compsn. from the foot of the single crystal to a coagulating grown single crystal by heating a crucible filled with a seed crystal and raw material for the solid crystal. CONSTITUTION:A crucible filled with a seed crystal and materials for a solid crystal is heated while changing continuously the relative position of the crucible to a heating device. A single crystal having a long size and uniform compsn. is obtd. by replenishing the material having different compsn. to the initially filled material continuously to a single crystal coagulated from the melt in the crucible. For example, by 0-5mol% Fe2O3 is reduced and by 0-5mol% MnO2 is increased, and by 0-5mol% ZnO is reduced preferably in a compsn. for the material for solid crystal to be replenished from the compsn. of the filled material for the solid crystal in the prepn. of an Mn-Zn ferrite single crystal.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is a method for producing long single crystals having a uniform composition while continuously replenishing a crucible filled with seed crystals and solid crystal raw materials. Regarding the manufacturing method.

[Conventional technology]

Conventionally, long single crystals are produced by filling seed crystals and solid crystal raw materials into a crucible heated by a heating device, melting these raw materials, and adjusting the relative positional relationship between the heating device and the crucible at a predetermined temperature distribution. The crucible is moved downward while being heated at different speeds, and a single crystal is grown at the bottom of the crucible. After the initial single crystal grows, as the crystal grows, the crucible is moved upwards and downwards while continuously replenishing solid crystal raw materials of the same composition in the form of powder, granules, or pellets at a constant rate per unit time. By moving the crystal, we obtained a long and large single crystal.

[Problem that the invention seeks to solve]

Conventionally, when obtaining a long single crystal, a fixed amount of the same type of solid crystal raw material is supplied and melted per unit time in a crucible that is continuously moving downward, but this results in compositional segregation in the longitudinal direction of the crystal. However, it is difficult to obtain a single crystal material with a uniform composition throughout, and a uniform portion must be selected, which has the disadvantage of being expensive.

[Means for solving problems]

The present invention eliminates such drawbacks of the conventional method by continuously supplying solid crystal raw materials of different compositions to a grown single crystal that is filled with nine seed crystals and a solid crystal raw material, heated, and solidified from below, thereby achieving a uniform composition over the entire length. This is a manufacturing method for obtaining single crystals.

〔Example〕

Embodiments of the present invention will be described using an example of Mn--Zn ferrite single crystal, which is generally widely used as a magnetic head core material. First, iron oxide u'ezos) 50.0mo1%
A ferrite raw material composed of 30.0 mo1% of manganese oxide (MnO) and 20.0 mo1% of zinc oxide (ZnO) was put into a platinum Ronram crucible.

After heating and melting in a heating device and completely melting, the crucible is lowered to the heating device, and when the growth of the single crystal progresses and the liquid phase reaches a certain range, single crystal raw materials with different composition ratios are supplied as supplementary raw materials. do.

The supplementary raw material supplied here is iron oxide u'e2o3)51
mo1%, manganese oxide (MnO) 28.5mol%
Zinc oxide (ZnO) is in the form of granules with a composition of 20.5 mol %, and is continuously replenished in a fixed amount per unit time. As shown in FIG. 1, this result shows that the composition (mol %) of each component relative to the length of the product is more uniform than before, and this is particularly effective in the initial stage.

〔Effect of the invention〕

As described above, according to the present invention, a long single crystal with a uniform composition over the entire length can be obtained, and the proportion of single crystal material having a desired composition obtained from one single crystal can be increased, reducing the cost. It can be measured.

[Brief explanation of drawings]

Claims (1)

[Claims] 1. A crucible filled with a seed crystal and a solid crystal raw material is heated by continuously changing the relative positional relationship with a heating device, and the solid crystal raw material is melted and solidified in the single crystal in the crucible. A method for producing a long single crystal with a uniform composition, characterized in that the filled solid crystal raw material and the replenishing solid crystal raw material have different compositions. 2. The ratio of the composition of the filled solid crystal raw material and the composition of the supplementary solid crystal raw material is set to 0 to 5 mol of FeO_3.
% less, MnO more than 0-5 mol%, ZnO 0-5 mol%
A method for producing a single crystal with a uniform composition according to claim 1, which relates to a Mn-Zn ferrite single crystal whose mol% is reduced.