JP5122045B2 - Oxide superconductor and manufacturing method thereof - Google Patents

Description

【００６３】
表１に示すように、基材の送出速度が高くなるにつれて、例えば試験例４〜７のごとく、薄膜の膜厚が小さくなって内部応力が低下し、基材から剥離しにくくなるが、粒界傾角が大きくなって配向性が低下していることが分かる。
一方、基材の送出速度が低下するにつれて、例えば試験例１〜３のごとく、粒界傾角が小さくなって配向性が向上するが、膜厚が大きくなって基材から剥離しやすくなっていることがわかる。
【００６４】
次に、表１に示した試験例のうち、基材からの剥離状況が良好であった試験例５〜７について、上記の薄膜を形成した際の条件と同一の条件で薄膜の形成を５〜２５回繰り返して行うことにより、試験例８〜１０の多結晶配向膜を形成した。得られた多結晶配向膜の膜厚、粒界傾角及び剥離状況を調査した。結果を表２に示す。尚、粒界傾角の測定及び表２中の剥離状況を示す各種印の意味は、表１の場合と同様である。
【００６５】
尚、比較例として、基材の送出速度を０．５ｍ／時間とし、入射角５５度に設定し、Ａｒ⁺のイオンビームのエネルギーを２００ｅＶ、イオン電流密度を１００μＡ／ｃｍ²に設定したこと以外は上記と同様にしてスパッタリングを連続して行うことにより、試験例１１の多結晶配向膜を形成した。粒界傾角及び剥離状況を表２に併せて示す。
【００６６】
【表２】

【００６７】
表２に示すように、試験例８〜１では、いずれも粒界傾角が小さく、配向性に優れていることが分かる。また、基材からの剥離状況については、試験例８の一部に剥離が認められたが、試験例９及び１０では全く剥離が見られず、良好な付着性を示すことが分かる。
一方、連続成膜により形成した試験例１１の多結晶配向膜は、粒界傾角が小さく配向性に優れるものの、成膜した多結晶配向膜のほぼ全部が剥離しており、付着特性が極めて低くなっている。これは、連続成膜により多結晶配向膜に内部応力が蓄積されたためと考えられる。
【００６８】
更に試験例９及び１０について、得られた多結晶配向膜上にイオンビームスパッタ装置を用いて酸化物超電導層を形成した。ターゲットとして、Ｙ_0.7Ｂａ_1.7Ｃｕ_3.0Ｏ_7-xなる組成の酸化物超電導体からなるターゲットを用いた。また、蒸着処理室の内部を１×１０^-6Torrに減圧してスパッタリングを行なった。その後、４００℃で６０分間、酸素雰囲気中において熱処理した。得られた酸化物超電導テープ導体は、幅１０.０ｍｍ、長さ２.５ｍのものである。
この酸化物超電導テープ導体を液体窒素により冷却し、中央部の幅１０ｍｍ、長さ１０ｍｍの部分について４端子法により臨界温度と臨界電流密度の測定を行なったところ、試験例９が臨界電流密度（０Ｔ、７７Ｋ）１．１×１０⁶Ａ／ｃｍ²を示し、試験例１０が臨界電流密度（０Ｔ、７７Ｋ）０．９×１０⁶Ａ／ｃｍ²を示し、いずれも良好な値を示した。
【００６９】
【発明の効果】
以上、詳細に説明したように、本発明の多結晶配向膜は、厚さ１〜１００ｎｍの複数の薄膜が積層されることにより形成されるので、各薄膜の内部応力を十分に小さくすることができ、これにより多結晶配向膜の全体の内部応力を低減させて多結晶配向膜の剥離を防止することができる。また、多結晶配向膜を構成する各結晶粒の粒界傾角が５〜２０度の範囲なので、結晶配向性に優れた多結晶配向膜を構成することができる。
【００７０】
また、本発明の多結晶配向膜の製造方法によれば、厚さ１０〜１００ｎｍの複数の薄膜を積層することにより多結晶配向膜を形成するので、多結晶配向膜を構成する各薄膜の内部応力を十分に小さくすることができ、これにより多結晶配向膜の全体の内部応力を低減させて、剥離しにくい多結晶配向膜を製造することができる。
【図面の簡単な説明】
【図１】 本発明方法により形成されたＹＳＺの多結晶配向膜を示す断面図である。
【図２】 図１に示すＹＳＺ多結晶配向膜を構成する薄膜の結晶粒とその結晶軸方向および粒界傾角を示す拡大平面図である。
【図３】 本発明方法を実施して基材上に多結晶配向膜を製造するための装置の一例を示す構成図である。
【図４】 図３に示す装置に設けられるイオンガンの一例を示す断面図である。
【図５】 図３に示す装置に設けられる冷却装置の一例を示す断面図である。
【図６】 図１に示すＹＳＺ多結晶配向膜の上に形成された酸化物超電導層を示す断面図である。
【図７】 イオンビームの入射角度と得られた多結晶配向膜の半値全幅との関係を示すグラフである。
【符号の説明】
Ａ…基材、Ｂ…多結晶配向膜、Ｃ…酸化物超電導層、Ｋ…粒界傾角、θ…入射角度、２０、２７…結晶粒、２１〜２５…薄膜、２６…酸化物超電導導体、３６…ターゲット、３８…イオンガン、３９…イオンソース、４０…成膜処理容器、Ｒ…冷却装置、６０…基台、６１…冷媒導入管、６２…往管、６３…戻管、７３…基材ホルダ、７４…第１ボビン、７５…第２ボビン[0001]
BACKGROUND OF THE INVENTION
  Invention,acidThe present invention relates to a chemical superconductor and a method for manufacturing the same.
[0002]
[Prior art]
The oxide superconductor discovered in recent years is an excellent superconductor exhibiting a critical temperature exceeding the liquid nitrogen temperature, but at present, to use this kind of oxide superconductor as a practical superconductor. There are various problems to be solved. One of the problems is that the critical current density of the oxide superconductor is low.
The problem that the critical current density of the oxide superconductor is low is largely due to the presence of electrical anisotropy in the oxide superconductor crystal itself. In particular, the oxide superconductor has its crystal axis. It is known that electricity can easily flow in the a-axis direction and b-axis direction, but it is difficult to flow electricity in the c-axis direction. From this point of view, in order to form an oxide superconductor on a base material and use it as a superconducting conductor, an oxide superconductor with good crystal orientation is formed on the base material, It is necessary to orient the a-axis or b-axis of the oxide superconductor crystal in the direction in which electricity is to flow and to orient the c-axis of the oxide superconductor in the other direction.
[0003]
Therefore, the present inventors first formed a YSZ (yttrium-stabilized zirconia) polycrystal orientation film with good a-axis and b-axis orientation on a polycrystal substrate using a special method. It has been found that if an oxide superconducting layer is formed on a polycrystalline alignment film, an oxide superconducting conductor exhibiting a good critical current density can be produced, and regarding this technique, Japanese Patent Application No. 4-293464, Patent applications have been filed in Japanese Patent Application No. 8-214806, Japanese Patent Application No. 8-272606, Japanese Patent Application No. 8-272607, and the like.
[0004]
The technology related to these patent applications is that when forming a film on a polycrystalline substrate using a YSZ target, Ar is obliquely formed with respect to the film-forming surface of the polycrystalline substrate.⁺By simultaneously irradiating ion beams such as YSZ crystals with poor crystal orientation, YSZ crystals with good crystal orientation can be selectively deposited, which results in orientation. It becomes possible to form a YSZ polycrystalline alignment film having excellent properties. The oxide superconductor formed on this polycrystalline alignment film can exhibit a good critical current density.
In particular, if the polycrystalline alignment film is formed at a low temperature, the smoothness of the alignment film surface is improved. If an oxide superconducting layer is formed on this smooth surface, the critical current density can be further improved. become.
[0005]
[Problems to be solved by the invention]
However, while the above-mentioned polycrystalline alignment film can provide an ideal smooth surface, Ar⁺Since the film is formed while simultaneously irradiating ion beams such as the above, internal stress may occur in the polycrystalline alignment film. If the adhesion force of the polycrystalline orientation film to the polycrystalline base material is not sufficient, the polycrystalline orientation film may be peeled off from the base material.
Since the internal stress of the polycrystalline alignment film tends to increase as the film thickness increases, it is necessary to limit the film thickness to prevent peeling. The crystal orientation of the physical superconducting layer is disturbed, and the critical current density may be lowered.
[0006]
The present invention has been made in view of the above circumstances, and can improve the critical current density and prevent peeling from the base material, and a manufacturing method thereof, an oxide superconductor, and a manufacturing method thereof. The purpose is to provide.
[0007]
[Means for Solving the Problems]
  In order to achieve the above object, the present invention employs the following configuration. In the oxide superconductor of the present invention, a plurality of thin films having a thickness of 10 to 100 nm formed by bonding a large number of crystal grains are laminated on at least a tape-shaped substrate, thereby forming the same crystal axis of the crystal grains. A polycrystalline alignment film having a grain boundary tilt angle in the range of 5 to 20 degrees is formed; the polycrystalline alignment film has a thickness of 300 to 2000 nm; and the superconducting oxide on the polycrystalline alignment film A layer is formed.
  In the present invention, the crystal grains constituting the thin film may be crystal grains having a cubic crystal structure..
[0014]
  According to the oxide superconductor, a plurality of thin films having a thickness of 10 to 100 nm are stacked.300-2000 nm thickSince the polycrystalline alignment film is provided, the internal stress of each thin film can be made sufficiently small, and the internal stress of the entire polycrystalline alignment film can be reduced to prevent the polycrystalline alignment film from peeling off. In addition, since the grain boundary tilt angle of each crystal grain constituting the polycrystalline alignment film is in the above range, the orientation of the polycrystalline alignment film is improved, thereby improving the orientation of the oxide superconducting layer, and the oxide superconductor. It becomes possible to increase the critical current density.
[0015]
Furthermore, in the method for producing an oxide superconductor of the present invention, a tape-like base material is fed into a film forming chamber, and particles generated from the target are deposited on the base material. An alignment film forming step of forming a polycrystalline alignment film made of an element and a large number of crystal grains bonded together, and a superconducting layer forming step of forming an oxide superconducting layer on the polycrystalline alignment film are provided. In the alignment film forming step, the ion beam generated by the ion source is irradiated from an oblique direction with respect to the normal line of the film formation surface of the substrate, and the target particles are deposited on the substrate to have a thickness of 10 The film forming step of forming a thin film of ˜100 nm is repeated at least twice, and the thin film is laminated, so that the grain boundary tilt angle formed by the same crystal axis of the crystal grains is in the range of 5 to 20 degrees. And forming said polycrystalline alignment film made Te.
[0016]
According to such a method for producing an oxide superconductor, a polycrystal having a grain boundary tilt angle formed by the same crystal axis of crystal grains within a range of 5 to 20 degrees by laminating thin films having a thickness of 10 to 100 nm. Since the alignment film is formed, the internal stress of each thin film constituting the polycrystalline alignment film can be sufficiently reduced to reduce the overall internal stress of the polycrystalline alignment film, and a polycrystalline alignment film that is difficult to peel off is manufactured. It becomes possible to do.
In addition, the grain boundary tilt angle of the polycrystalline orientation film is in the above range, and the orientation of the polycrystalline orientation film is excellent, so that the crystal orientation of the oxide superconducting layer can be enhanced and the oxide superconductivity having a high critical current density. The body can be manufactured.
[0017]
Moreover, the manufacturing method of the oxide superconductor of the present invention is the manufacturing method of the oxide superconductor described above, and the tape-shaped base material is fed into the film forming chamber at a delivery speed of 2 to 20 m / hour. In addition, the ion beam is irradiated from an oblique direction at an incident angle in the range of 50 to 60 degrees with respect to the normal of the film formation surface of the substrate, and the temperature during film formation is set in the range of 60 to 200 ° C. It is characterized by doing.
[0018]
According to the method for manufacturing an oxide superconductor, the tape-shaped base material feed speed is set in the range of 2 to 20 m / hour, and the ion beam incident angle and the temperature during film formation are set in the above range. As a result, the thickness of the thin film constituting the polycrystalline alignment film can be reduced to 100 nm or less, and the internal stress of the thin film can be reduced to prevent peeling of the polycrystalline alignment film. Further, by setting the delivery speed within the above range, the thickness of the thin film becomes 10 nm or more, thereby improving the crystal orientation of the thin film and improving the orientation of the polycrystalline alignment film, and further the orientation of the oxide superconducting layer. Therefore, it is possible to manufacture an oxide superconductor having improved criticality and excellent critical current density.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic perspective view showing an embodiment in which a polycrystalline alignment film of the present invention is formed on a substrate, and FIG. 2 is a schematic plan view of a thin film (25) shown in FIG. In FIG. 1, A is a tape-like polycrystalline substrate, and B is a polycrystalline alignment film formed on the upper surface of the polycrystalline substrate A.
The polycrystalline base material A can be used in various shapes such as a plate material, a wire material, and a tape material, and the polycrystalline base material A is made of Ni alloy such as silver, platinum, stainless steel, copper, hastelloy, etc. It is made of a metal material, an alloy, or a material such as various glasses or various ceramics.
[0020]
As shown in FIG. 1, the polycrystalline alignment film B is formed by laminating a plurality of thin films 21 to 25 having a thickness of 10 to 100 nm formed by bonding a large number of crystal grains 20 (in FIG. 1). 5 thin films). Each thin film 21 to 25 is formed by joining and integrating fine crystal grains 20 of YSZ having a cubic crystal structure with each other through a grain boundary, and the c-axis of the crystal axis of each crystal grain 20. Are oriented at right angles to the upper surface (film formation surface) of the substrate A, and the a axes and the b axes of the crystal axes of the crystal grains 20 are oriented in the same direction in the same direction.
2, the a-axis (or b-axis) of the crystal grains 20 constituting the thin film 25 has an angle formed between them (grain boundary inclination angle K shown in FIG. 2) within a range of 5 to 20 degrees. Are joined and integrated.
Although only the crystal structure of the thin film 25 has been described with reference to FIG. 2, the crystal structures of the other thin films 21 to 24 are substantially the same as the crystal structure of the thin film 25, and the orientation becomes sharper as the layers are stacked.
Note that the value of the grain boundary inclination angle K can be adjusted by controlling the temperature during film formation in a suitable range in the method for producing the polycrystalline alignment film B described later, and can be adjusted by controlling the temperature during film formation. It can be adjusted to a predetermined value.
[0021]
As described above, the thickness of each thin film 21 to 25 is preferably in the range of 10 to 100 nm. If the film thickness of the thin films 21 to 25 is less than 10 nm, it is difficult to maintain the film thickness stably and the film thickness varies, which is not preferable. If the film thickness of the thin films 21 to 25 exceeds 100 nm, each of the thin films 21 to 25 is not preferable. This increases the internal stress of the polycrystalline alignment film B, thereby increasing the internal stress of the entire polycrystalline alignment film B, which is not preferable because the polycrystalline alignment film B is easily peeled off from the polycrystalline substrate A. The film thickness of the thin films 21 to 25 can be increased or decreased by adjusting the delivery speed of the polycrystalline base material A as will be described later.
[0022]
The thickness of the polycrystalline alignment film B can be adjusted by adjusting the film thickness of each thin film 21 to 25 or increasing or decreasing the number of thin film stacks, preferably in the range of 300 to 2000 nm, and in the range of 500 to 1500 nm. Is more preferable. If the thickness of the polycrystalline alignment film B is less than 300 nm, it is not preferable because the grain boundary inclination angle K formed by the crystal grains 20 cannot be in the above range. If the thickness exceeds 2000 nm, the entire polycrystalline alignment film B is not preferable. This is not preferable because the internal stress increases and the polycrystalline alignment film B is easily peeled off from the polycrystalline base material A.
The reason why the internal stress of the entire polycrystalline alignment film B can be reduced by laminating the thin films 21 to 25 is compared with the case where the internal stress is accumulated by continuously forming the polycrystalline alignment film as in the prior art. Thus, it is considered that the internal stress of each of the thin films 21 to 25 is not accumulated by intermittently repeating the formation of the thin film, thereby relaxing the internal stress of the entire polycrystalline alignment film.
[0023]
FIG. 3 is a diagram showing an example of a polycrystalline alignment film manufacturing apparatus suitably used for carrying out the polycrystalline alignment film manufacturing method of the present invention.
In this example, the polycrystalline alignment film manufacturing apparatus supports a tape-shaped substrate A and is capable of heating or cooling to a desired temperature, and a block-shaped substrate holder 73 and a tape-shaped substrate holder 73. A first bobbin 74 for feeding or winding the base material A, and a second bobbin for winding or feeding the tape-shaped base material A on which the polycrystalline alignment film (B) is formed in conjunction with the first bobbin 74 75, a plate-like target 36 that is opposed to the substrate holder 73 diagonally above at a predetermined interval, and a sputtering beam irradiation device (sputtering means) that is arranged obliquely above the target 36 toward the lower surface of the target 36. 38, the ion source 39 facing the side of the substrate holder 73 at a predetermined interval and spaced apart from the target 36, and the cooling device R can be evacuated. It has a configuration which is provided to an empty chamber (film forming treatment vessel) 40.
In this example, the polycrystalline alignment film manufacturing apparatus repeatedly reciprocates the tape-shaped base material A on the base material holder 73 by the first bobbin 74 and the second bobbin 75, and the particles generated from the target 36 in the meantime. By depositing on the substrate A during reciprocal movement, a thin film made of the constituent elements of the target is formed on the substrate A, and a polycrystalline alignment film is formed by laminating a plurality of these thin films.
[0024]
The base material holder 73 is configured to include a heater 73a made of a metal wire or the like that generates resistance when energized, and the tape-like base material A that reciprocates on the base material holder 73 is brought to a desired temperature as necessary. It can be heated. Such a substrate holder 73 is disposed in the optimum irradiation region of the ion beam irradiated from the ion source 39 in the film formation processing container 40. Further, the base material holder 73 is provided by being mounted on a side triangular base 60, and the base 60 is formed by a refrigerant introduction pipe 61 provided through the outer wall 40 a of the film formation processing container 40. A cooling device R is configured by being mainly supported by a base 60 and a refrigerant introduction pipe 61 supported by the central portion of the container 40.
[0025]
The base 60 in this form is made of a hollow metal block having a triangular cross section as shown in FIG. 5, and its upper surface 60a can make the incident angle of the ion beam with respect to the base material to be described later in the range of 50 to 60 degrees. The surface is inclined. In addition, a refrigerant introduction pipe 61 is connected to the back surface 60b of the base 60, and the refrigerant introduction pipe 61 has a double structure including an internal forward pipe 62 and a return pipe 63 covering the outside. Both the pipe 62 and the return pipe 63 communicate with the internal space of the base 60 inside the chamber, and both of them extend substantially horizontally and pass through the outer wall 40a of the film formation processing vessel 40 to the outside. Both pipes are led out and are curved upward, and an injection part 64 is formed at the distal end of the forward pipe 62 so as to protrude slightly above the distal end of the return pipe 63. A funnel-shaped injection member 65 is mounted.
[0026]
The distal end portion of the outgoing pipe 62 on the base 60 side and the distal end portion of the return pipe 63 on the base 60 side are both hermetically joined to the connection holes on the back surface 60b of the base 60, so that the film forming process container Even when the inside of the base 40 is depressurized, the inside of the base 60 can be brought into an atmospheric pressure state outside the film formation processing container, and a liquid refrigerant such as liquid nitrogen or cooling air can be placed inside the above-described injection member 65. A gas refrigerant or the like is fed in so that the interior of the base 60 can be filled with the refrigerant.
[0027]
The forward pipe 62 and the return pipe 63 are provided so that when the refrigerant introduction pipe 61 is constituted by the forward pipe 62 alone, the refrigerant is introduced into the injection member 65 and the refrigerant is sent from the forward pipe 62 to the base 60. This is also to prevent the refrigerant that has been previously sent from staying in the base 60 and preventing new refrigerant from being supplied to the base 60. If the return pipe 63 is provided at this point, the old refrigerant staying in the base 60 can be easily discharged into the atmosphere through the return pipe 63, so that the base 60 is always fresh. The base 60 can be sufficiently cooled by supplying the refrigerant, and the cooling capacity can be increased. Further, if a double structure in which the outside of the outward pipe 62 is covered with the return pipe 63 is adopted, the forward pipe 62 can be covered with the refrigerant passing through the return pipe 63. The forward pipe 62 can be cooled with this refrigerant, and it is possible to prevent the temperature of the refrigerant from being unnecessarily increased inside the forward pipe 62.
[0028]
Further, the refrigerant supply pipe 61 is provided through the flange plate 66, and the flange plate 66 closes the mounting hole 40b formed in the outer wall 40a of the film formation processing container 40, and is fixed to the outer wall 40a by screws or the like. It is detachably fixed. A temperature measuring device 67 for measuring the temperature of the base 60 is attached to the flange plate 66 so as to be adjacent to the refrigerant supply pipe 61, and the substrate holder 73 is connected by a temperature sensor 68 connected to the temperature measuring device 67. It is comprised so that the temperature of can be measured. That is, when the base material holder 73 is set on the upper surface 60a of the base 60 as shown by a two-dot chain line in FIG. 5, the temperature of the base material holder 73 is controlled by keeping the temperature sensor 68 in contact with the base material holder 73. It is configured so that it can be measured.
[0029]
From the above, the base material holder 73 is heated to a temperature higher than normal temperature by the heater 73a and the base material A is heated, or the base material A is cooled by the base 60, so that the base material A is desired. The temperature can be adjusted to, for example, a temperature in the range of + 500 ° C. to −196 ° C. That is, heating can be easily adjusted from room temperature to about 500 ° C. by heating the heater, and further, the heater is stopped and a cooling medium such as liquid nitrogen, air, cooling air, or cooling gas is used as a cooling medium. It can be easily cooled to about 77K (about −196 ° C.) by the above cooling device.
[0030]
Since the cooling device R used here is not limited to the one shown in FIG. 5, it is a cooling device using fluorine gas such as chlorofluorocarbon or ammonia used in a normal cooling device such as a cooler, and is about −30 ° C. Of course, an apparatus capable of cooling may be provided. Further, since the substrate is naturally heated by the arrival of hot particles from the target during film formation, for example, the substrate is 100 when the film is formed at room temperature and the substrate holder is not heated or cooled at all. It will be heated to about ℃. Moreover, when forming into a film, cooling with a refrigerant | coolant, the capability to cool the base material A from the base 60 can be adjusted by adjusting the material and thickness of the base material holder 73 which supply a base material.
For example, if the substrate holder 73 that is thin and excellent in thermal conductivity is used and the supply amount of liquid nitrogen from the refrigerant introduction pipe 61 is sufficiently secured, even if the heat generated during film formation is subtracted, it can be easily reduced to about −150 ° C. In contrast, by forming the base material holder 73 with a thick metal material, the cooling capacity from the base 60 can be kept low. In this case, even if a liquid nitrogen refrigerant is used, The temperature of the material A can be easily adjusted to about −150 to −50 ° C.
However, in the present invention, since the temperature at the time of film formation may be in the range of 60 to 200 ° C. as described later, excessive cooling is unnecessary, and a refrigerant (for example, cooling air) that can be adjusted to a temperature range of 60 to 200 ° C. , Cooling water, etc.) may be used as appropriate by adjusting the flow rate.
[0031]
In the manufacturing apparatus of the polycrystalline alignment film B of this example, the tape-shaped substrate A is continuously sent out from the first bobbin 74 or the second bobbin 75 onto the substrate holder 73 to pass through the optimum irradiation region, A plurality of thin films can be sequentially stacked on the substrate A by repeating the winding / feeding-out operation of the base A by the two bobbins 75 or the first bobbins 74 a plurality of times.
[0032]
The target 36 is used to form a target polycrystalline alignment film, and a target having the same composition as or an approximate composition of the target polycrystalline alignment film can be used. Specifically, the target 36 is MgO or Y₂O_ThreeThe stabilized zirconia (YSZ) is used, but the present invention is not limited to these, and a target corresponding to the composition of the polycrystalline alignment film to be formed may be used as appropriate. The target 36 is rotatably attached to the target support 36a by a pin or the like so that the inclination angle can be adjusted.
The sputter beam irradiation device (sputtering means) 38 is configured to store an evaporation source inside the container and to include a grid for applying a drawing voltage in the vicinity of the evaporation source. The constituent particles of the target 36 can be knocked out toward the base material A by irradiating the beam.
[0033]
The ion source 39 has substantially the same configuration as that of the sputter beam irradiation device 38, and includes a grid for storing an evaporation source inside the container and applying an extraction voltage in the vicinity of the evaporation source. And it is an apparatus which ionizes the atom or a part of molecule | numerator which generate | occur | produced from the said evaporation source, and irradiates it as an ion beam by controlling the ionized particle | grain with the electric field generated in the grid. There are various types of ionization of particles such as a direct current discharge method, a high frequency excitation method, a filament method, and a cluster ion beam method. The filament type is a method in which a tungsten filament is energized and heated to generate thermoelectrons and collide with evaporated particles in a high vacuum to be ionized. In the cluster ion beam system, clusters of aggregate molecules coming out in a vacuum from a nozzle provided in an opening of a crucible containing raw materials are bombarded with thermal electrons and ionized to be emitted.
[0034]
In the polycrystalline alignment film manufacturing apparatus, an ion source 39 having an internal structure shown in FIG. 4 is used. The ion source 39 includes a cylindrical ion chamber 45 having a grid 46, a filament 47, and an introduction tube 48 such as Ar gas. The ion source 39 forms a beam from a beam port 49 at the tip of the ion chamber 45. It can radiate substantially in parallel. The installation position of the ion source 39 can be changed, and the diameter d of the beam port 49 can also be changed.
[0035]
As shown in FIG. 3, the ion source 39 has its central axis S with respect to the film-forming surface of the substrate A and an incident angle θ (an angle formed between the normal (normal) H of the substrate A and the center line S). So they are inclined and face each other. The incident angle θ is preferably in the range of 50 to 60 degrees, more preferably in the range of 55 to 60 degrees, and most preferably 55 degrees. Therefore, the ion source 39 is arranged so that the ion beam can be irradiated at a certain incident angle θ with respect to the normal H of the film formation surface of the substrate A.
[0036]
In addition, the ion source 39 has a spread angle Δθ of an ion beam radiated from the following formula (I):
Δθ ≦ 2tan^-1(D / 2L) (I)
(Where Δθ is the divergence angle of the ion beam, d is the beam aperture (cm) of the ion source 39, and L is the distance between the beam aperture 49 of the ion source 39 and the substrate A (cm). Therefore, the ion beam transport distance L and the beam aperture d are set in accordance with the crystal orientation of the target polycrystalline orientation film. The ion beam spread angle Δθ is preferably 5 degrees or less, and more preferably 3 degrees or less. For example, in the case of L = 40 cm, Δθ ≦ 5 ° can be controlled if d ≦ 3.49 cm, and Δθ ≦ 3 ° can be controlled if d ≦ 2.09 cm.
[0037]
The ion beam applied to the substrate A by the ion source 39 is He when the YSZ intermediate layer is formed.⁺, Ne⁺, Ar⁺, Xe⁺, Kr⁺Or the like, or a mixed ion beam of these and oxygen ions.
[0038]
Further, the film formation processing vessel 40 is connected to a rotary pump 51 and a cryopump 52 for bringing the inside of the film formation processing vessel 40 into a low pressure state such as a vacuum, and an atmospheric gas supply source such as a gas cylinder, respectively. The inside of the film-forming treatment container 40 can be in a low-pressure state such as a vacuum, and an argon gas or other inert gas atmosphere or an inert gas atmosphere containing oxygen can be formed.
Furthermore, a current density measuring device 54 for measuring the current density of the ion beam in the film formation processing container 40 and a pressure gauge 55 for measuring the pressure in the container 40 are attached to the film formation processing container 40. It has been.
In the polycrystalline alignment film manufacturing apparatus of this embodiment, an angle adjustment mechanism may be attached to the support portion of the ion source 39 to adjust the tilt angle of the ion source 39 and adjust the incident angle of the ion beam. Of course, the angle adjusting mechanism can employ various configurations. Further, the ion beam transport distance L can be changed by changing the installation position of the ion source 39. However, the ion beam transport can be performed by adjusting the length of the support 73a of the substrate holder 73. The distance L may be changed.
[0039]
Next, a method of forming the YSZ polycrystalline alignment film B on the tape-shaped substrate A using the manufacturing apparatus having the above-described configuration will be described.
In this method, particles produced from a target are deposited on a tape-like substrate to produce a polycrystalline alignment film that is composed of constituent elements of the target and in which a large number of crystal grains are bonded. While feeding the tape-shaped substrate into the film chamber, the ion beam generated by the ion source is irradiated from an oblique direction with respect to the normal of the film forming surface of the substrate and target particles are deposited on the substrate. The film forming step for forming a thin film having a thickness of 10 to 100 nm is repeated at least twice, and the thin film is laminated, whereby the grain boundary tilt angle formed by the same crystal axis of the crystal grains is in the range of 5 to 20 degrees. The above-described polycrystalline alignment film is formed.
In the production method of the present invention, MgO or Y is used to form a polycrystalline alignment film on the tape-shaped substrate A.₂O_ThreeThe target 36 made of zirconia (YSZ) stabilized by the above method is used to evacuate the inside of the film formation processing container 40 containing the substrate A to form a reduced-pressure atmosphere, and from the first bobbin 74 to the substrate holder The base material A is fed to 73 at a feed rate of 2 to 20 m / hour, and the ion source 39 and the sputter beam irradiation device 38 are operated.
In addition, when the feeding speed of the base material is less than 2 m / hour, the orientation of the crystal grains 20 becomes high, but the thickness of the thin film increases and the internal stress increases, and the thin film 21 easily peels from the base material A. Therefore, it is not preferable, and if the delivery speed exceeds 20 m / hour, the thickness of the thin film is reduced and the internal stress is reduced, but the orientation of the crystal grains 20 is reduced, which is not preferable.
[0040]
Further, the heater or cooling device attached to the substrate holder 73 is operated to adjust the temperature of the substrate A in contact with the substrate holder 73 to a temperature in the range of 50 to 200 ° C.
The set temperature of the base material A is set in a range of 50 to 200 ° C. based on the results of crystal orientation of YSZ described later, data on critical current density of a superconducting layer described later, and various test results such as a film forming rate. It is preferable to do.
[0041]
By the way, when the refrigerant is charged into the injection member 65 and filled in the internal space of the base 60 through the outgoing pipe 62 from here, the heated state by the deposited particles or other apparatus provided in the film formation processing container 40 The base material A can be easily adjusted to a temperature slightly higher than the temperature of the refrigerant by heat radiation from, and can be easily adjusted to around 100 ° C., particularly when no refrigerant is used at room temperature. In order to adjust to the temperature range, the heater 73 may be energized. To adjust to the temperature range of 60 to 100 ° C., a small amount of refrigerant such as cooling water or cooling air may be used while adjusting the flow rate.
[0042]
When the target 36 is irradiated with an ion beam from the sputtering beam irradiation device 38, the constituent particles of the target 36 are knocked out and fly onto the base material A.
Then, the constituent particles knocked out from the target 36 are deposited on the base material A fed onto the base material holder 73 and simultaneously from the ion source 39, for example, Ar⁺A thin film 21 having a desired thickness is formed by irradiation with a mixed ion beam of ions and oxygen ions, and the tape-shaped substrate A after the film formation is wound around the second bobbin 75.
[0043]
Here, the incident angle θ when irradiating the ion beam is preferably in the range of 50 to 60 degrees, more preferably in the range of 55 to 60 degrees, and most preferably 55 degrees. Here, if θ is 90 degrees, the c-axis of the thin film 21 is oriented at right angles to the film formation surface on the substrate A, but the in-plane orientation becomes very broad, which is not preferable.
By performing sputtering while irradiating with an ion beam at such an incident angle, the a-axis and the b-axis of the crystal axis of the YSZ thin film 21 formed on the substrate A are oriented in the same direction. In-plane orientation is performed along a plane parallel to the upper surface (film formation surface) of the material A.
[0044]
Thus, the thin film 21 having a thickness of 10 to 100 nm is formed on the base material A by performing the film forming step in which the feed speed of the base material, the incident angle θ, and the temperature of the base 60 are set in the above range. It is formed.
[0045]
Next, the substrate A with the thin film 21 wound around the second bobbin is fed toward the substrate holder 73 at a speed of 2 to 20 m / hour, and is wound around the first bobbin. By performing the same film forming process again, the constituent particles of the target 36 are deposited on the thin film 21 and at the same time, the mixed ion beam is irradiated from the ion source 39 to form the desired thickness thin film 22. Thus, the thin film 22 is laminated on the thin film 21 by performing the same film forming process as that of the thin film 21.
[0046]
By performing the above-described series of film forming steps at least twice, a polycrystalline alignment film B having a thickness of 10 to 100 nm formed by laminating a plurality of thin films 21 to 25 on the substrate A can be produced. . The thickness of the polycrystalline alignment film B can be increased or decreased by adjusting the thickness of each thin film 21 to 25 formed in one film forming process or the number of film forming processes.
[0047]
Then, the oxide superconducting conductor 26 having the structure shown in FIG. 6 is formed by laminating the oxide superconducting layer C on the polycrystalline alignment film B formed as described above by a film forming method such as sputtering or laser deposition. Can be obtained.
The oxide superconducting layer C is coated on the upper surface of the polycrystalline orientation film B, and the c-axis of the crystal grain 27 is oriented perpendicular to the upper surface of the polycrystalline orientation film B, and the crystal grain 27 The a-axis and b-axis of ... are aligned in-plane along a plane parallel to the upper surface of the base material in the same manner as the polycrystalline alignment film B described above, and the grain boundary inclination angle formed by the crystal grains 27 exceeds 1 m. On a scale substrate, for example, on a 2.5 m substrate, the grain boundary tilt angle is 26 degrees or less, and in part, it is formed to a small value of 20 degrees or less (for example, 12 to 20 degrees). Has been.
[0048]
The oxide superconductor constituting this oxide superconducting layer is Y₁Ba₂Cu_ThreeO_7-x, Y₂Ba_FourCu₈O_y, Y_ThreeBa_ThreeCu₆O_yThis is a Y-based oxide superconductor having a high critical temperature typified by such a composition.
[0049]
Here, the oxide superconducting layer C is formed by the film forming method such as sputtering or laser vapor deposition on the polycrystalline alignment film B with the grain boundary tilt angle accurately aligned in the range of 5 to 20 ° as described above. Then, the oxide superconducting layer C laminated on the polycrystalline orientation film B is also epitaxially grown and crystallized so as to match the orientation of the polycrystalline orientation film B.
Therefore, the oxide superconducting layer C formed on the polycrystalline orientation film B is hardly disturbed in the crystal orientation, and in each of the crystal grains 27 constituting the oxide superconducting layer C, the base material A The c-axis in which electricity is difficult to flow is oriented in the thickness direction, and the a-axis or b-axis is oriented in the length direction of the substrate A. Therefore, the obtained oxide superconducting layer C is excellent in quantum connectivity at the grain boundaries and has almost no deterioration of the superconducting characteristics at the grain boundaries. And SrTO_ThreeA sufficiently high critical current density of the same level as that of the oxide superconducting layer obtained on the single crystal substrate can be obtained.
[0050]
As described above, by laminating a plurality of thin films 21 to 25, it is possible to obtain a polycrystalline alignment film B having low internal stress and excellent crystal orientation, and oxide superconductivity is formed on the polycrystalline alignment film B. By forming the layer C, the oxide superconducting conductor 22 having excellent crystal orientation and high critical current characteristics can be obtained.
In addition, the oxide superconducting conductor obtained in this example can be easily formed into a long tape with excellent flexibility with a length exceeding 1 m, and application to a winding of a superconducting magnet can be expected. In addition, the oxide superconducting conductor 22 according to the present invention is resistant to bending because the polycrystalline alignment film B is difficult to peel off. Therefore, even when a superconducting coil is manufactured by winding it around a winding drum, the superconducting characteristics are deteriorated. A superconducting coil can be obtained in the absence of this.
[0051]
In addition, the present inventors assume the following about the factor and the film-forming rate in which the crystal orientation of the polycrystalline orientation film B is arranged.
The unit lattice of the crystal of the YSZ polycrystalline alignment film B is a cubic crystal, the substrate normal direction of this crystal lattice is the (100) axis, and the (010) axis and the (001) axis are both in other directions. Become. Considering the ion beam incident from the oblique direction with respect to the substrate normal to these directions, when entering the diagonal direction of the unit cell relative to the origin of the unit cell, that is, along the (111) axis The incident angle with respect to the substrate normal is 54.7 degrees.
[0052]
According to the technology previously filed by the inventors of the present application, as shown in FIG. 7, the full width at half maximum indicating the crystal orientation of the polycrystalline orientation film of YSZ obtained according to the incident angle of the ion beam is The minimum value is exhibited when the ion beam incident angle is in the range of 55 to 60 degrees.
Here, as described above, good crystal orientation is exhibited in the incident angle range of 50 to 60 degrees because the ion channeling is performed when the incident angle of the ion beam coincides with or is around 54.7 degrees. In the crystal deposited on the base material A, only the atoms in the arrangement relationship corresponding to the angle on the upper surface of the base material A are likely to remain selectively, and other disordered atoms It is presumed that the arrayed elements are removed by being sputtered by the sputtering effect of the ion beam, so that only crystals with a good orientation of atoms are selectively left and deposited.
[0053]
At this time, the irradiation effect of the ion beam on YSZ has two effects, that is, the effect of raising the (100) plane of YSZ perpendicular to the substrate and the effect of adjusting the in-plane orientation. It is presumed that the effect of raising the (100) plane perpendicularly to the main is the main. This is because if the effect of raising YSZ (100) perpendicular to the substrate is insufficient, the in-plane orientation is inevitably disturbed.
[0054]
Next, if the temperature is controlled within a range suitable for film formation while irradiating an ion beam at an incident angle of 50 to 60 degrees with respect to the normal of the film formation surface, the grain boundary inclination angle K of the polycrystalline alignment film B is controlled. The inventor of the present application estimates the reason why the value of is favorable, in other words, the reason why the crystal orientation of the polycrystalline alignment film B is good.
In order to obtain a thin film with good crystallinity in a film formation method such as normal sputtering or laser vapor deposition, film formation is performed while heating the film formation atmosphere to a high temperature, for example, about 400 to 600 ° C. or higher. That is common knowledge. Obtaining a film with high crystallinity by forming a film while heating to such a high temperature means that there is a close relationship between the film formation temperature and crystallization, In the field of thin film production, it is understood that when the film formation temperature is low, a film rich in amorphousness is easily generated.
[0055]
However, in the case of using a film forming technique accompanying ion beam irradiation, which is a technique related to the present invention, the film forming temperature is preferably as low as possible because the effect of adjusting the crystal by the ion beam is extremely large. This is because the lower the temperature, the less the movement and vibration of the atoms that make up the crystal, and the more effective the effect of aligning the crystal with ion beam irradiation is. It is estimated that the alignment film B is easily generated.
[0056]
That is, according to the technique of the present invention, a polycrystalline orientation film having a stable (100) axis can be obtained as the temperature is lowered, and accordingly, the angle of the (111) axis is uniquely determined, and De-channeling (dechanneeling) does not occur due to thermal vibration of constituent atoms, and the cross-sectional area of ions along the (111) axis is reduced, enabling effective orientation control and improving crystal orientation. I think that the.
In addition, the polycrystalline orientation film B having higher crystal orientation can be obtained as the film formation temperature becomes lower, and the polycrystalline orientation film having better crystal orientation when the polycrystalline orientation film B is formed at a temperature of 200 ° C. or lower. The fact that the alignment film B can be obtained is contrary to the knowledge that it is difficult to obtain a film with high crystallinity without film formation while heating at a high temperature in a general film formation technique. In this case, the peculiarity of the technique for forming a film while irradiating the ion beam from an oblique direction can be known.
[0057]
However, if the film formation temperature is too low, the crystal orientation tends to decrease in a thin film with a short film formation time. This is a state before the state in which crystals are aligned with good alignment in a thin film. That is, it is considered that the crystal orientation is likely to be insufficient because a film in which atoms before the crystals are sufficiently arranged is likely to be somewhat disordered. However, even in the case of low-temperature film formation, it is possible to obtain a film having excellent crystal orientation by securing the necessary film thickness by forming a sufficient film thickness over several tens of hours. This is not preferable from the viewpoint of manufacturing efficiency.
In view of the above, a polycrystalline intermediate layer having a certain required film thickness (a film thickness of about 300 nm or more as a film thickness necessary for starting deposition while the atoms to be deposited are sufficiently oriented by the effect of the ion beam) is formed on the substrate. In order to form the film efficiently, it is considered preferable to perform the film forming process in a temperature range of 60 to 200 ° C.
[0058]
According to the above oxide superconductor, since the polycrystalline alignment film B formed by laminating a plurality of thin films 21 to 25 having a thickness of 10 to 100 nm is provided, the internal stress of each thin film 21 to 25 is sufficiently reduced. Further, the internal stress of the entire polycrystalline alignment film B can be reduced and peeling of the polycrystalline alignment film B can be prevented.
In addition, since the grain boundary tilt angle of each crystal grain constituting the polycrystalline alignment film B is in the range of 5 to 20 degrees, the orientation of the polycrystalline alignment film is improved, thereby improving the orientation of the oxide superconducting layer C. The critical current density of the oxide superconductor can be increased.
[0059]
In addition, according to the method for manufacturing an oxide superconductor described above, by laminating thin films 21 to 25 having a thickness of 10 to 100 nm, the grain boundary tilt angle formed by the same crystal axis of crystal grains is in the range of 5 to 20 degrees. Since the polycrystalline alignment film B is formed, the internal stress of each of the thin films 21 to 25 constituting the polycrystalline alignment film B is sufficiently reduced to reduce the overall internal stress of the polycrystalline alignment film B. Thus, a polycrystalline alignment film that is difficult to peel off can be manufactured.
Further, the grain boundary tilt angle of the polycrystalline alignment film B is in the above range, and the orientation of the polycrystalline alignment film B is excellent, so that the crystal orientation of the oxide superconducting layer C can be enhanced and has a high critical current density. An oxide superconductor can be manufactured.
[0060]
【Example】
The apparatus having the configuration shown in FIGS. 3 to 5 was used to perform sputtering with ion beam irradiation to form a YSZ polycrystalline alignment film in which a plurality of thin films were laminated on a metal tape. The inside of the vacuum vessel containing the apparatus shown in FIG. 3 is evacuated with a vacuum pump to 3.0 × 10^-FourWhile reducing the pressure to Torr, Ar + O in the vacuum vessel₂16.0 sccm for Ar gas, O₂The gas was supplied at a rate of 8.0 sccm.
As a base material, a tape of Hastelloy C276 alloy (Ni: 58%, Mo: 17%, W5%, Cr14%, Fe6%) having a width of 10 mm, a thickness of 0.5 mm, and a length of 2.5 m, having a mirror-finished surface. used. The target is YSZ (Y₂O_Three: 8 mol%), Ar⁺The target is irradiated with ions from the ion gun and sputtered, and the incident angle of the ion beam from the ion gun is set to an incident angle of 55 degrees with respect to the normal of the film surface of the base tape on the base holder.⁺The ion beam energy is 200 eV and the ion current density is 100 μA / cm.²The ion beam irradiation is performed simultaneously with the laser deposition on the base material, and the base tape is moved on the base tape while moving the base tape along the base material holder at a delivery speed of 0.1 to 5.0 m / hour. A thin film was formed. In this way, samples of Test Examples 1 to 7 were obtained.
[0061]
During the film formation, the heater of the base material holder was operated to control the temperature of the base material and the polycrystalline alignment film at the time of film formation to 100 ° C.
For each of the obtained Test Examples 1 to 7, the substrate feeding speed, the film thickness of the thin film, the grain boundary tilt angle, and the peeling state of the thin film were investigated. The results are shown in Table 1. The grain boundary tilt angle was defined as the full width at half maximum (FWMH) obtained from the (111) pole figure and (100) pole figure by X-rays as the grain boundary tilt angle Δψ. In Table 1, among the symbols indicating the peeling status, a circle indicates no peeling, a Δ mark indicates a partial peeling, and a cross indicates a complete peeling.
[0062]
[Table 1]

[0063]
As shown in Table 1, as the delivery speed of the substrate increases, for example, as in Test Examples 4 to 7, the film thickness of the thin film decreases and the internal stress decreases, making it difficult to peel from the substrate. It can be seen that the field inclination angle is increased and the orientation is lowered.
On the other hand, as the feed rate of the base material decreases, for example, as in Test Examples 1 to 3, the grain boundary tilt angle decreases and the orientation improves, but the film thickness increases and it is easy to peel from the base material. I understand that.
[0064]
Next, among the test examples shown in Table 1, with respect to Test Examples 5 to 7 in which the peeling state from the substrate was good, formation of the thin film was performed under the same conditions as those when the above thin film was formed. By repeating the process 25 times, the polycrystalline alignment films of Test Examples 8 to 10 were formed. The thickness, grain boundary tilt angle, and peeling state of the obtained polycrystalline alignment film were investigated. The results are shown in Table 2. Incidentally, the measurement of the grain boundary tilt angle and the meanings of various marks indicating the peeling state in Table 2 are the same as those in Table 1.
[0065]
As a comparative example, the base material delivery speed was set to 0.5 m / hour, the incident angle was set to 55 degrees, and Ar⁺The ion beam energy is 200 eV and the ion current density is 100 μA / cm.²The polycrystalline alignment film of Test Example 11 was formed by continuously performing sputtering in the same manner as described above except that it was set to be. Table 2 shows the grain boundary tilt angle and the peeling state.
[0066]
[Table 2]

[0067]
As shown in Table 2, it can be seen that in Test Examples 8 to 1, the grain boundary tilt angle is small and the orientation is excellent. Moreover, about the peeling condition from a base material, although peeling was recognized in a part of Test Example 8, in Example 9 and 10, peeling is not seen at all, and it turns out that favorable adhesiveness is shown.
On the other hand, although the polycrystalline alignment film of Test Example 11 formed by continuous film formation has a small grain boundary tilt angle and excellent orientation, almost all of the formed polycrystalline alignment film is peeled off, and the adhesion characteristics are extremely low. It has become. This is thought to be because internal stress was accumulated in the polycrystalline alignment film by continuous film formation.
[0068]
Further, for Test Examples 9 and 10, an oxide superconducting layer was formed on the obtained polycrystalline alignment film using an ion beam sputtering apparatus. Y as target_0.7Ba_1.7Cu_3.0O_7-xA target made of an oxide superconductor having the following composition was used. The inside of the vapor deposition chamber is 1 × 10^-6Sputtering was performed while reducing the pressure to Torr. Thereafter, heat treatment was performed in an oxygen atmosphere at 400 ° C. for 60 minutes. The obtained oxide superconducting tape conductor has a width of 10.0 mm and a length of 2.5 m.
The oxide superconducting tape conductor was cooled with liquid nitrogen, and the critical temperature and critical current density were measured by a four-terminal method for a central portion having a width of 10 mm and a length of 10 mm. 0T, 77K) 1.1 × 10⁶A / cm²Test Example 10 is critical current density (0T, 77K) 0.9 × 10⁶A / cm²Both showed good values.
[0069]
【Effect of the invention】
As described above in detail, since the polycrystalline alignment film of the present invention is formed by laminating a plurality of thin films having a thickness of 1 to 100 nm, the internal stress of each thin film can be sufficiently reduced. Accordingly, the internal stress of the entire polycrystalline alignment film can be reduced and peeling of the polycrystalline alignment film can be prevented. Moreover, since the grain boundary inclination angle of each crystal grain constituting the polycrystalline alignment film is in the range of 5 to 20 degrees, it is possible to configure a polycrystalline alignment film having excellent crystal orientation.
[0070]
In addition, according to the method for producing a polycrystalline alignment film of the present invention, a polycrystalline alignment film is formed by laminating a plurality of thin films having a thickness of 10 to 100 nm. The stress can be made sufficiently small, thereby reducing the overall internal stress of the polycrystalline alignment film and producing a polycrystalline alignment film that is difficult to peel off.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a YSZ polycrystalline alignment film formed by the method of the present invention.
2 is an enlarged plan view showing crystal grains of a thin film constituting the YSZ polycrystalline alignment film shown in FIG. 1, its crystal axis direction, and grain boundary tilt angle. FIG.
FIG. 3 is a configuration diagram showing an example of an apparatus for producing a polycrystalline alignment film on a substrate by carrying out the method of the present invention.
4 is a cross-sectional view showing an example of an ion gun provided in the apparatus shown in FIG.
5 is a cross-sectional view showing an example of a cooling device provided in the apparatus shown in FIG.
6 is a cross-sectional view showing an oxide superconducting layer formed on the YSZ polycrystalline alignment film shown in FIG.
FIG. 7 is a graph showing the relationship between the incident angle of an ion beam and the full width at half maximum of the obtained polycrystalline alignment film.
[Explanation of symbols]
A ... Base material, B ... Polycrystalline orientation film, C ... Oxide superconducting layer, K ... Grain boundary tilt angle, θ ... Incident angle, 20, 27 ... Crystal grain, 21-25 ... Thin film, 26 ... Oxide superconducting conductor, 36 ... Target, 38 ... Ion gun, 39 ... Ion source, 40 ... Film formation processing vessel, R ... Cooling device, 60 ... Base, 61 ... Refrigerant introduction pipe, 62 ... Outgoing pipe, 63 ... Return pipe, 73 ... Base material Holder, 74 ... first bobbin, 75 ... second bobbin

Claims (4)

  A grain boundary tilt angle formed by the same crystal axis of the crystal grains is 5 to 20 degrees by laminating a plurality of thin films having a thickness of 10 to 100 nm formed by bonding a large number of crystal grains on at least a tape-like substrate. A polycrystalline alignment film having a thickness of 300 to 2000 nm, and an oxide superconducting layer is formed on the polycrystalline alignment film. Oxide superconductor.   The oxide superconductor according to claim 1, wherein the crystal grains constituting the thin film are crystal grains having a cubic crystal structure.   A tape-shaped base material is fed into the film forming chamber, and particles generated from the target are deposited on the base material, so that a large number of crystal grains are combined with the constituent elements of the target on the base material. An alignment film forming step for forming a polycrystalline alignment film, and a superconducting layer forming step for forming an oxide superconducting layer on the polycrystalline alignment film. In the alignment film forming step, an ion source is generated. A film forming step of forming a thin film having a thickness of 10 to 100 nm by irradiating the ion beam from the oblique direction with respect to the normal of the film forming surface of the base material and depositing target particles on the substrate; By laminating the thin film at least twice or more, the grain boundary inclination angle formed by the same crystal axis of the crystal grains is set in a range of 5 to 20 degrees, and a multi-crystal having a film thickness of 300 to 2000 nm is formed. Method of manufacturing an oxide superconductor and forming an alignment film. The tape-shaped substrate is fed into the film forming chamber at a delivery speed of 2 to 20 m / hour, and the ion beam is incident at an angle of incidence in the range of 50 to 60 degrees with respect to the normal of the film forming surface of the substrate. The method for producing an oxide superconductor according to claim 3 , wherein the temperature is set in a range of 60 to 200 ° C.

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