JPH0637349B2 - Method for producing liquid-phase epitaxy gal-net film - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a liquid phase epitaxial garnet film, and more particularly to a liquid phase epitaxial method for a bismuth-substituted garnet film for a high density magnetic bubble device.

[Conventional technology]

Conventionally, as a melt for producing a bismuth-substituted garnet film for a high-density magnetic bubble device by a liquid phase epitaxial method, lead oxide and bismuth oxide are used as solvent components, and iron oxide, garnet components such as rare earth oxides are used as solutes. The composition is known. Boron oxide (B ₂ O ₃ ) may be added as a solvent component. The molar ratio R ₁ ([Fe ₂ O ₃ ] / Σ [R ₂ O ₃ ]) of iron oxide to total rare earth oxide is 1
5 to 50 are used.

[Problems to be solved by the invention]

The above-mentioned conventional technique has the following problems in manufacturing the epitaxial film. That is, firstly, in the melt containing bismuth oxide, flux remains in the LPE film, and defects easily occur, and secondly, the flux erodes platinum, which is the material of the crucible. The present invention provides a manufacturing method that solves these problems.

[Means for solving problems]

The present invention contains a rare-earth oxide, iron oxide, and a molten coating composition containing lead oxide as a main solvent component, wherein the cell ratio to lead oxide is 0.1 or more bismuth oxide and 0.1 or more vanadium oxide, The molar ratio of iron oxide to the total rare earth oxide is 3 or more and less than 15. A method for producing a liquid phase epitaxial garnet film.

〔Example〕

Below, it demonstrates still in detail using an Example. iron oxide
118.3g, bismuth oxide 714.5g, vanadium oxide 278.9g, lead oxide 1711.2g, samarium oxide 9.30g, lutetium oxide 12.
A melt consisting of 97 g was prepared by melting it in a platinum crucible at 1000 ° C. The molar ratio of bismuth oxide and vanadium oxide to lead oxide in this melt is both 0.2. The molar ratio of iron oxide to the total rare earth oxide is 12.5. Epitaxial growth was performed from this melt at 870 ° C. for 30 seconds on a samarium gallium garnet (SmGG) substrate. The epitaxial film became a submicron bubble material for high density devices with a characteristic length of 0.05 μm. 1 Observation by a Maruski microscope revealed that the epitaxial film surface had no crystal defects and was a good quality film. This is due to the fact that the flux is well-broken and it is difficult for the flux to remain. The erosion amount of the platinum crucible by the flux was about 50 mg or less each time the epitaxial film was grown.
This was about one-tenth the amount of conventional lead oxide and bismuth oxide (molar ratio 5: 1) melts that did not contain vanadium oxide. The amount of bismuth contained in the film was 0.6 per molecular formula, which was sufficient.

When the amount of bismuth oxide contained in the melt is less than 0.1 with respect to lead oxide, the epitaxial film is substituted. Not suitable because the amount of bismuth is too low. Also, if the amount of vanadium oxide is less than 0.1, the effects of the invention described above do not appear, which is not suitable. The content of bismuth oxide and vanadium oxide is at least 0.1 or more, preferably 0.
Two or more is preferable, but since it depends on other growth conditions such as the degree of supercooling, it should be optimized in the individual melt design.
However, it is desirable that the amount be smaller than that of lead oxide.

When the ratio R ₁ of iron oxide to rare earth oxide is R ₁ = 15, although garnet can be epitaxially grown on the substrate, magnetoplumbite nucleation is observed in the melt, and the phase diagram shows the first garnet Since it is not in the crystal zone,
A good quality film could not be obtained. According to the experiment, the range of R _{1 at} which garnet can stably grow epitaxially is 3
Above, less than 15. It is considered that this is because when V ₂ O ₅ is present in the melt, the activity of Fe ³⁺ increases and the primary crystal region of garnet changes.

Further, at this time, the surface tension is increased, so that the fusion angle of the flux with respect to the crystal surface is increased, the wettability is reduced, and the flux is less likely to remain. At the same time, when V ₂ O ₅ is contained, R ₁ becomes a small melt, so Fe ₂ O ₃ contained in the melt is reduced. This also contributes to the fact that the flux is less likely to remain.

Regarding the erosion of the platinum crucible, when V ₂ O ₅ is not contained, the phenomenon in which the melt melts into platinum oxide near the boundary between the platinum crucible and the melt when the melt temperature is low and the melt melts The phenomenon of reduction and precipitation of metallic platinum at high temperature was repeated, but when V ₂ O ₅ was contained, V ₂ O ₅ served as an oxidant and melted. Corrosion does not proceed because the phenomenon of precipitation of metallic platinum does not occur when the temperature of the liquid becomes high.

〔The invention's effect〕

As mentioned above, the PbO-Bi ₂ O ₃ was added to Bi ₂ O ₃ and V ₂ O ₅ in the melt for bismuth-substituted garnet as the flux, also the _{R 1} parameter, 3 ≦ R ₁ <15
With this, it is possible to prevent the flux from remaining and to prevent the platinum crucible from corroding. As a result, the problem of epitaxial growth of the conventional bismuth-substituted garnet film can be solved, and the productivity of the high density magnetic bubble device can be improved.

Claims (1)

[Claims] 1. Rare earth oxide (R ₂ O ₃ , where R means rare earth element and yttrium), iron oxide (Fe)
₂ O ₃ ) In a method for producing a liquid phase epitaxial garnet film using a melt containing lead oxide (PbO) as a main solvent component, the melt has a molar ratio with respect to lead oxide of bismuth oxide (Bi ₂ O _{3) of} 0.1 or more. ) And vanadium oxide of 0.1 or more
A method for producing a liquid phase epitaxial garnet film, which comprises (V ₂ O ₅ ) and contains iron oxide in a molar ratio of less than 15 and 3 or more based on all rare earth oxides.