JPS609329B2 - Method for manufacturing magnetic thin film for magnetic bubble device using liquid phase epitaxial growth method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a magnetic thin film for a magnetic bubble element using a liquid phase epitaxial growth method.

Generally, a magnetic thin film for a magnetic bubble element is made of a single crystal such as orthoferrite or magnetic garnet, and there are various methods for manufacturing this magnetic thin film, but the most common method is liquid phase epitaxial growth.

Conventionally, when manufacturing a magnetic thin film, such as a garnet film, by the epitaxial growth method, a large number of garnet pus is obtained by processing the same melt many times.

However, this method has the drawback that the solute in the melt gradually changes each time the pus grows, and the quality of the obtained garnet film changes, making it impossible to form a large number of homogeneous garnet films. There is. As a countermeasure, a method is used to manufacture a homogeneous garnet film by lowering the temperature of the liquid phase epitaxial and maintaining the melt quality constant for each individual garnet film. Even with this method, the temperature eventually becomes too low,
This method has the disadvantage that a large number of garnet films cannot be obtained because the number of treatments is limited. Therefore, an object of the present invention is to enable the production of a large number of homogeneous magnetic thin films such as garnet films using the same melt.

In order to achieve such an object, the present invention supplies melt components into the melt every time a magnetic thin film is formed a certain number of times, and will be described in detail below using Examples.

Normally, in the epitaxial growth method, the inner diameter is 7 m,
In a platinum crucible with a height of 70 ribs, Pb0. Solvent with a predetermined composition ratio of B203 and Y203, S■03, Ga203, Fe
The raw material oxide such as 203 is loaded and the saturation temperature (approximately 90
0 to 1000°C) and maintained at a temperature approximately 200°C higher for approximately 2q hours.

Next, the temperature is maintained at about 1 pi○ lower than the saturation temperature. By immersing a seed substrate such as gadolinium, gallium, or garnet single crystal thin plate in the melt thus obtained, (YSm)3(GaFe) or garnet film 2 can be epitaxially grown. In this case, each time a film is grown, the concentration of the raw material oxide in the melt decreases due to film growth, and the solute changes. For this reason, in order to obtain a garnet film having the same characteristics when the next film is grown, the temperature of the melt must be lowered so that the growth rate is the same as the above-mentioned rate. This method may be repeated many times in order to perform multiple treatments on the same melt. but,
If this is repeated many times, the temperature will become much lower than the initial growth temperature and the melt itself will solidify, and even before that, the growth rate will decrease because the diffusion rate of the solute particles in the melt increases. This may cause problems such as delays. Therefore, there is a drawback that a large number of magnetic thin films cannot be obtained.
This point has been outlined above. Therefore,
In the present invention, every time a film with a thickness of 6.5 mm is grown a certain number of times, for example, 5 times on a seed substrate of gadolinium, gallium, garnet single crystal thin plate, etc. on the diameter irregular side,
Some or all of the melt components are added to the base melt.

This compensates for changes in the components of the base melt, returning the base melt to its original state, and also makes the liquid phase epitaxial temperature more complex, forming a large number of magnetic thin films such as garnet films with the same characteristics. It is something. Examples of the present invention will be described below. In this example, first, a solvent and a raw material oxide having the above-mentioned composition to obtain the desired magnetic bubble characteristics are loaded into a platinum rubbo with an inner diameter of 7 ribs and a height of 7 ribs, and a saturation of about 900 to 1000 qo is carried out. The temperature is maintained at about 200 degrees higher than the temperature for a certain period of time.

The reason why the temperature is raised to about 200°C is to sufficiently melt the raw material oxides and the like to form a good melt. Next, the temperature is set to several degrees Celsius lower than the saturation temperature. In this state, for example 6. A magnetic thin film of & is grown by liquid phase epitaxial method. Then, this growth is repeated five times to obtain five films. In this growth, the growth temperature gradually becomes lower, and in the fifth growth, it is lowered by about 3° C. than the initial temperature. This is to keep the port quality constant. Powders of various substances in amounts consumed by film growth are then added to the melt according to the following table. Thereafter, the temperature is maintained at a temperature 20 degrees higher than the saturation temperature for a certain period of time, and after the powder is sufficiently melted, the temperature is returned to a predetermined temperature.

Thereafter, by repeating the same steps, a homogeneous garnet film can be obtained using the same melt. Figure 1a
, b, and c show the changes in the growth temperature of the liquid phase, the bubble presence area of the garnet film, and the width of the garnet film with respect to the number of treatments. By supplying the amount of various substances consumed each time, the growth temperature characteristics can be set to the curves m, n, 0, and P, which are almost the same as the curves for the first waist growth. can. Therefore, the bubble existence region of each garnet film obtained in this way and the magnetic domain width of the garnet film are almost constant, as is clear from figures b and c.
A homogeneous garnet film can be obtained. Next, regarding the method of supplying powder such as oxides, one possible method is to use a funnel with a long tube and supply the powder from the outside into the melt through this tube. However, when the powder passes through the tube, a large amount of powder remains attached to the side wall of the tube, resulting in a disadvantage that the appropriate amount of powder cannot be accurately supplied.

FIG. 2 shows a powder feeding device according to the present invention, which was made in consideration of this point.

In the figure, reference numeral 1 denotes an electric furnace having a cavity la extending in the vertical direction and equipped with a heating element 2. In the cavity la, a platinum rubbo 4 supported by a support part 3 is disposed, and the platinum rubbo 4 is disposed in the cavity la. The crucible 4 contains a mother melt 5. Reference numeral 6 denotes a platinum rubbo 4 for storing replenishment powder 7, and a platinum wire 8 is connected to the bottom and upper ends of the sides.

In such a configuration, an appropriate amount of replenishment powder is put into the small platinum crucible 6, the small platinum crucible 6 is suspended by a platinum wire 8, positioned above the melt 5 of the platinum crucible 4, and one side of the platinum wire 8 is pulled up. By raising the bottom of the small platinum rubbo 6, all of the replenishment powder 7 is supplied into the melt 5. Therefore, according to such a method, the amount of powder remaining on the side wall of the platinum lip 6 becomes extremely small, and the V supply operation becomes quick and easy. Here, in this example, it was explained that replenishment of powder is repeated every 5 times, but as long as the temperature is within the temperature range that allows pus to grow (approximately 10 degrees Celsius), replenishment may be repeated any number of times. good.

Further, in this example, a case was explained in which a garnet film was manufactured, but the present invention is not limited thereto, and the present invention can also be applied to a case where an orthoferrite film is manufactured.

Also, in this example. , a platinum rod wire may be used instead of the platinum wire 8 explained in FIG.

As explained above, according to the method of manufacturing a magnetic thin film for a magnetic bubble element using the liquid phase epitaxial growth method according to the present invention, each time a magnetic thin film for a magnetic bubble element is formed several times using the same melt, the components of the final melt are was supplied into the melt in an appropriate amount to fix the temperature within a certain temperature range. This prevents the melt from solidifying, making it possible to obtain a large number of magnetic thin films with the same melt, and because the diffusion rate of solute atoms in the melt increases, magnetic thin films can be obtained quickly. It has great effects.

[Brief explanation of the drawings] Figure 1 a, b, and c show the growth temperature of the liquid phase for the treatment process,
FIG. 2 is a characteristic diagram showing the bubble existence region of the garnet film and changes in the magnetic domain width. FIG. 2 is a simplified configuration diagram showing an embodiment of the powder supply device according to the present invention. DESCRIPTION OF SYMBOLS 1... Electric furnace, 2... Heating element, 3... Support part, 4
... Platinum crucible, 5... Base melt, 6... Small platinum rubbo, 7... Replenishment powder, 8... Platinum wire. Figure 1 Little brother Z diagram

Claims (1)

[Claims] 1. Each time a magnetic thin film for a magnetic bubble element is formed using the same melt several times, an appropriate amount of the components of the melt are supplied into the melt to compensate for changes in the volumetric concentration of the melt and form the magnetic film. 1. A method for manufacturing a magnetic thin film for a magnetic bubble element using a liquid phase epitaxial growth method, characterized in that the temperature of the melt during the process is fixed within a certain temperature range.