JP3038485B2 - Bi-based oxide superconducting thin film - Google Patents
Bi-based oxide superconducting thin filmInfo
- Publication number
- JP3038485B2 JP3038485B2 JP2119235A JP11923590A JP3038485B2 JP 3038485 B2 JP3038485 B2 JP 3038485B2 JP 2119235 A JP2119235 A JP 2119235A JP 11923590 A JP11923590 A JP 11923590A JP 3038485 B2 JP3038485 B2 JP 3038485B2
- Authority
- JP
- Japan
- Prior art keywords
- thin film
- class
- superconductor
- superconducting thin
- critical temperature
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/60—Superconducting electric elements or equipment; Power systems integrating superconducting elements or equipment
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明はBi系酸化物超伝導薄膜に関し、特に、超伝導
特性を有し、高い臨界温度を有するBi−Pb−Sr−Ca−Cu
−Ｏ系及びBi−Sr−Ca−Cu−Ｏ系を含むBi系超伝導薄膜
に関するものである。The present invention relates to a Bi-based oxide superconducting thin film, in particular, Bi-Pb-Sr-Ca-Cu having superconductivity and a high critical temperature.
The present invention relates to a Bi-based superconducting thin film including -O-based and Bi-Sr-Ca-Cu-O-based.
Bi系超伝導体は、臨界温度が100K以上の優れた材料で
あることは広く知られている。この材料は、前田らによ
り発見（Japanese Journal of Applied Physics,27（19
88）,L209〜210）されて以来、電子材料及びデバイス等
へ応用するために、各所で薄膜化が行われている。It is widely known that Bi-based superconductors are excellent materials having a critical temperature of 100K or more. This material was discovered by Maeda et al. (Japanese Journal of Applied Physics, 27 (19
88), since L209-210), thinning has been performed in various places for application to electronic materials and devices.
しかしながら、この材料には110K級、80K級及び半導
体相の三種類の多形が存在し、しかも110K級超伝導体の
生成温度領域が狭いため単相化が難しい。従来、単相11
0K級超伝導薄膜を合成するには、熱処理前の組成として
ほぼBi:Pb:Sr:Ca:Cu＝1:1:1:1:1.5若しくはCaを過剰に
加えた薄膜を約850℃で熱処理していた（例えばJapanes
e Journal of Applied Physics,28（1989）,L819〜82
2）。However, this material has three types of polymorphs, 110K class, 80K class, and semiconductor phase, and it is difficult to form a single phase due to the narrow temperature range in which a 110K class superconductor is formed. Conventionally, single phase 11
To synthesize a 0K class superconducting thin film, the composition before heat treatment is almost Bi: Pb: Sr: Ca: Cu = 1: 1: 1: 1: 1.5 or a thin film with excess Ca added is heat-treated at about 850 ° C. (For example, Japanes
e Journal of Applied Physics, 28 (1989), L819-82
2).
薄膜中に生成した板状の110K級超伝導体のｃ軸長と臨
界温度の関係についての報告は少ないが、例えばJapane
se Journal of Applied Physics,28（1989）,L646〜649
にｃ軸の格子定数が小さいほど臨界温度が高いと報告さ
れている。There are few reports on the relationship between the c-axis length and the critical temperature of a plate-like 110K-class superconductor formed in a thin film.
se Journal of Applied Physics, 28 (1989), L646-649
It is reported that the smaller the lattice constant of the c-axis, the higher the critical temperature.
本発明の目的は、多形の存在する超伝導薄膜につい
て、薄膜中の110K級超伝導体のｃ軸長と臨界温度との関
係から臨界温度の高いBi系超伝導薄膜を提供しようとす
るものである。An object of the present invention is to provide a Bi-based superconducting thin film having a high critical temperature from the relationship between the c-axis length of the 110K class superconductor and the critical temperature in the superconducting thin film in which the polymorph exists. It is.
本発明者らは、製造した薄膜を種々条件で熱処理を行
い、得られた薄膜のｃ軸長と臨界温度の関係を調べた結
果、単相110K級超伝導体の合成にこだわることなく、生
成薄膜中の110K級超伝導体相のｃ軸長によって、高臨界
温度の超伝導薄膜を選択できることを見出して、本発明
を完成するに到った。The present inventors performed heat treatment on the manufactured thin film under various conditions, and examined the relationship between the c-axis length and the critical temperature of the obtained thin film. The inventors have found that a superconducting thin film having a high critical temperature can be selected depending on the c-axis length of the 110K-class superconductor phase in the thin film, and have completed the present invention.
すなわち、本発明は、Bi,Pb,Sr,Ca及びCu、又はBi,S
r,Ca及びCuを含む（Bi＋Pb）2Sr2Ca2Cu3Ox構造の110K級
酸化物超伝導体と、（Bi＋Pb）2Sr2Ca1Cu2Ox構造の80K
級酸化物超伝導体から構成され、その組成が、 BiaPbbSr1.00CacCudOx であって、組成中のａ、ｂ、ｃ及びｄが、 0.5≦ａ≦1.2 0.0≦ｂ≦1.2 0.4≦ｃ≦1.3 1.3≦ｄ≦2.0 である薄膜において、110K級酸化物超伝導体のｃ軸が3.
7100nm以上であることを特徴とする臨界温度が100k以上
のBi系超伝導薄膜である。That is, the present invention, Bi, Pb, Sr, Ca and Cu, or Bi, S
110K class oxide superconductor of (Bi + Pb) 2 Sr 2 Ca 2 Cu 3 O x structure containing r, Ca and Cu, and 80 K of (Bi + Pb) 2 Sr 2 Ca 1 Cu 2 O x structure
Grade superconductor, the composition of which is Bi a Pb b Sr 1.00 Ca c Cu d O x , wherein a, b, c and d in the composition are 0.5 ≦ a ≦ 1.2 0.0 ≦ b In a thin film in which ≦ 1.2 0.4 ≦ c ≦ 1.3 1.3 ≦ d ≦ 2.0, the c-axis of the 110K-class oxide superconductor is 3.
A Bi-based superconducting thin film having a critical temperature of 100 k or more, which is characterized by being 7100 nm or more.
以下詳細に説明する。 This will be described in detail below.
110K級超伝導体結晶の（Bi＋Pb）2Sr2Ca2Cu3Ox構造
は、80K級超伝導対結晶の（Bi＋Pb）2Sr2Ca1Cu2Ox構造
中のｃ軸方向に垂直な面にCa層とCu−Ｏ層が入り込んで
構成される。その際、Ca層とCu−Ｏ層が十分に入り込ま
ないと、110K級超伝導体としての特性が発揮されない。
また、Ca層とCu−Ｏ層が理論組成よりも多く結晶構造中
に取り込まれると、110K級超伝導体の特性よりも落ち
る。すなわち、110K級超伝導体の結晶構造であっても、
ｃ軸長が3.7100nm以上でないと部分的に80K級超伝導体
が含まれることになり、抵抗曲線は低温側に裾を引き、
臨界温度が低下する。The (Bi + Pb) 2 Sr 2 Ca 2 Cu 3 O x structure of the 110K-class superconductor crystal is perpendicular to the c-axis direction in the (Bi + Pb) 2 Sr 2 Ca 1 Cu 2 O x structure of the 80K-class superconductor pair crystal. It is constituted by a Ca layer and a Cu-O layer entering the surface. At that time, if the Ca layer and the Cu-O layer do not sufficiently enter, the properties as a 110K class superconductor cannot be exhibited.
Further, when the Ca layer and the Cu-O layer are incorporated in the crystal structure more than the theoretical composition, the properties of the 110K class superconductor deteriorate. That is, even if the crystal structure of the 110K class superconductor,
If the c-axis length is not more than 3.7100 nm, the 80K class superconductor will be partially included, and the resistance curve will have a tail on the low temperature side,
Critical temperature decreases.
得られるBi系超伝導薄膜の110K級超伝導体結晶として
そのｃ軸長が3.7100nm以上のものを合成する超伝導薄膜
製造方法については、後記する製造方法において、薄膜
組成、特にCa/Sr原子比、焼成温度、焼成時間等が相互
に影響しあっていると考えられる。The superconducting thin film manufacturing method for synthesizing a Bi-based superconducting thin film having a c-axis length of 3.7100 nm or more as a 110K-class superconducting crystal is described in the manufacturing method described below. It is considered that the ratio, the firing temperature, the firing time, and the like influence each other.
本発明における薄膜の製造方法は、スパッタリング
法、蒸着法等の物理的手法により行われる。The method for producing a thin film in the present invention is performed by a physical method such as a sputtering method and a vapor deposition method.
薄膜を製造する際、スパッタリングターゲットの数及
び蒸着源の数は特に限定しない。つまり、基板上に堆積
した薄膜の組成が上記の範囲であればよい。When manufacturing a thin film, the number of sputtering targets and the number of evaporation sources are not particularly limited. That is, the composition of the thin film deposited on the substrate may be within the above range.
Biは0.5より少ないと超伝導体の結晶構造が構成され
にくく、1.2より多いと80K級超伝導体と半導体相を生成
する。Pbも1.2より多いと80K級超伝導体と半導体相を生
成し易い。Caは0.4より少ないと半導体相を生成し、1.3
より多いと110K相は生成するが、CaCu2O3やCa2CuO3など
の不純物が同時に生成するため、臨界温度が低下する。
Cuは1.3より少ないと80K級超伝導体を生成し、2.0より
多いと80K級超伝導体と半導体を生成する。If the content of Bi is less than 0.5, it is difficult to form a superconductor crystal structure, and if the content of Bi is more than 1.2, an 80K-class superconductor and a semiconductor phase are formed. If Pb is more than 1.2, an 80K-class superconductor and a semiconductor phase are easily formed. If Ca is less than 0.4, a semiconductor phase is formed, and 1.3
If the amount is more, the 110K phase is generated, but the impurities such as CaCu 2 O 3 and Ca 2 CuO 3 are simultaneously generated, so that the critical temperature is lowered.
When Cu is less than 1.3, 80K class superconductor is generated, and when it is more than 2.0, 80K class superconductor and semiconductor are generated.
用いられる基板としては、熱処理中に薄膜中の元素と
反応しないMgO、SrTiO3、LaGaO3、LaAlO3等の酸化物単
結晶、Ag、Au、Pt、Cu等の多結晶金属、Si、GaAs等の半
導体、又はこれらを組み合わせたものなどが使用され
る。Substrates used include oxide single crystals such as MgO, SrTiO 3 , LaGaO 3 and LaAlO 3 which do not react with elements in the thin film during heat treatment, polycrystalline metals such as Ag, Au, Pt, Cu, Si, GaAs, etc. Or a combination thereof.
薄膜の厚さは、使用目的に合わせて製造し、好ましく
は0.1〜10nm程度がよい。薄膜の厚さが0.1μｍ以下だと
熱処理後、超伝導粒子同志の結合が弱くなり、10μｍ以
上だと膜の配向性が著しく低下し、臨界電流密度等の超
伝導特性が低下する。The thickness of the thin film is manufactured according to the purpose of use, and is preferably about 0.1 to 10 nm. When the thickness of the thin film is 0.1 μm or less, the bonding between superconducting particles becomes weak after heat treatment, and when the thickness is 10 μm or more, the orientation of the film is remarkably reduced, and the superconducting properties such as critical current density are reduced.
薄膜製造の際、基板加熱は行っても行わなくてもよ
い。Substrate heating may or may not be performed during thin film production.
また、ターゲットの原料は、酸化物、炭酸化物、硝酸
化物等の無機化合物、又は、各単体の金属、二種類以上
の合金が用いられる。In addition, as a raw material of the target, an inorganic compound such as an oxide, a carbonate, or a nitrate, a single metal, or an alloy of two or more types is used.
作製された薄膜は、結晶化させるために800〜860℃で
５〜100時間熱処理し、110K級超伝導体を合成する。ま
た、熱処理の前に700〜800℃で２〜10時間予め仮焼する
と膜の特性が安定する。熱処理後は、炉内で冷却する。
熱処理は、空気中もしくはPbOの蒸気が存在する雰囲気
等の酸素存在化で行う。The produced thin film is heat-treated at 800 to 860 ° C. for 5 to 100 hours to crystallize, thereby synthesizing a 110K class superconductor. If the film is calcined at 700 to 800 ° C. for 2 to 10 hours before the heat treatment, the characteristics of the film are stabilized. After the heat treatment, it is cooled in a furnace.
The heat treatment is performed in the presence of oxygen such as in air or in an atmosphere in which PbO vapor is present.
以下の測定において110K級超伝導体結晶のｃ軸長は、
Ｘ線回折装置を用い、試料の回折線のうち（002），（0
06），（008），（0010），（0014），（0016），（002
4），（0026），（0032），（0034）の回折ピーク位置
を、Si粉末を標準試料として、その（220），（311），
（400），（331），（422），（333）の回折角度から補
正した。補正したピーク位置を面間隔ｄに直して最小二
乗法で計算した。計算には、Ｘ線結晶解析用プログラム
UNICS RSLC−３を用いた。In the following measurements, the c-axis length of the 110K class superconductor crystal is
Using an X-ray diffractometer, (002), (0
06), (008), (0010), (0014), (0016), (002)
4) The diffraction peak positions of (0026), (0032), and (0034) were determined using the Si powder as a standard sample and the (220), (311),
Correction was made from the diffraction angles of (400), (331), (422), and (333). The corrected peak position was converted to the surface distance d and calculated by the least square method. X-ray crystal analysis program
UNICS RSLC-3 was used.
また、臨界温度は、クライオスタット中で四端子法に
より測定した。The critical temperature was measured in a cryostat by a four-terminal method.
超伝導薄膜の製造 スパッタリングターゲット Bi0.5Pb0.5Ox 第一のターゲットとしてBi2O3とPbOの粉末を、原子比
でBi:Pb＝1:1となるように配合し、メタノール中で24時
間混合して乾燥したもの。Production of superconducting thin film Sputtering target Bi 0.5 Pb 0.5 O x Bi 2 O 3 and PbO powder are blended as the first target so that the atomic ratio of Bi: Pb = 1: 1, and then mixed in methanol for 24 hours What was mixed and dried.
CaCu0.75Ox 第二のターゲットとして、CaCO3とCuOの粉末を、原子
比でCa:Cu＝1:0.75に配合し、上記方法と同様に混合し
た粉末を、950℃で10時間空気中で焼成し粉砕したも
の。CaCu 0.75 O x As a second target, a powder of CaCO 3 and CuO was blended in an atomic ratio of Ca: Cu = 1: 0.75, and the powder mixed in the same manner as above was heated at 950 ° C. for 10 hours in air. Fired and crushed.
SrCu0.75Ox 第三のターゲットとして、SrCO3とCuOの粉末を、原子
比でSr:Cu＝1:0.75となる様に配合し、上記方法と同様
に混合した粉末を、950℃で10時間空気中で焼成し粉砕
したもの。SrCu 0.75 O x As a third target, a powder of SrCO 3 and CuO was blended in an atomic ratio of Sr: Cu = 1: 0.75, and the powder mixed in the same manner as above was heated at 950 ° C. for 10 hours. Fired and crushed in air.
加熱されていないMgO単結晶基板上に、上記３種類の
ターゲットを用い、RFパワーを100Wとして、Arガスでス
パッタリングし、各ターゲットの堆積が一巡したら、こ
れを400回くり返して約２μｍの薄膜を得た。On the unheated MgO single crystal substrate, using the above three types of targets, sputtering at an RF power of 100 W, and Ar gas, and when the deposition of each target has completed one cycle, this is repeated 400 times to form a thin film of about 2 μm. Obtained.
各ターゲットの一回の堆積時間は Bi0.5Pb0.5Ox ８秒 CaCu0.75Ox （53.5＋Ｘ）秒 SrCu0.75Ox （53.5−Ｘ）秒 とし、Ｘとして10、５及び０を選び、次の三種類の組成
の薄膜を得た。The single deposition time of each target was Bi 0.5 Pb 0.5 O x 8 seconds CaCu 0.75 O x (53.5 + X) seconds SrCu 0.75 O x (53.5-X) seconds, and X was selected from 10, 5 and 0. Thin films of three compositions were obtained.
Ａ） Ｘ＝10:（Bi＋Pb）1.69Sr1.00Ca1.17Cu1.87Ox Ｂ） Ｘ＝5:（Bi＋Pb）1.47Sr1.00Ca0.92Cu1.80Ox Ｃ） Ｘ＝0:（Bi＋Pb）1.36Sr1.00Ca0.80Cu1.59Ox 得られたそれぞれの薄膜を850℃で、15時間、24時間
及び65時間熱処理した。A) X = 10: (Bi + Pb) 1.69 Sr 1.00 Ca 1.17 Cu 1.87 O x B) X = 5: (Bi + Pb) 1.47 Sr 1.00 Ca 0.92 Cu 1.80 O x C) X = 0: (Bi + Pb) 1.36 Sr 1.00 Ca 0.80 Cu 1.59 O x Each of the obtained thin films was heat-treated at 850 ° C. for 15, 24, and 65 hours.
得られた超伝導薄膜について、各試料の110K級超伝導
体のｃ軸長及び臨界温度を測定した結果を表−１に示
す。Table 1 shows the results of measuring the c-axis length and the critical temperature of the 110 K class superconductor of each sample for the obtained superconducting thin film.
〔発明の効果〕 本発明のBi系酸化物超伝導薄膜は、その薄膜を構成す
る110K級超伝導体結晶のｃ軸長が3.7100nm以上の場合、
その臨界温度は100K以上あり、優れた超伝導特性を示
す。 (Effect of the Invention) Bi-based oxide superconducting thin film of the present invention, when the c-axis length of 110K class superconductor crystal constituting the thin film is 3.7100nm or more,
Its critical temperature is over 100K and it shows excellent superconducting properties.
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 平２−74528（ＪＰ，Ａ) 特開 平２−59403（ＪＰ，Ａ) 特開 平３−265523（ＪＰ，Ａ) 特開 平２−141425（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) C01G 1/00 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-74528 (JP, A) JP-A-2-59403 (JP, A) JP-A-3-265523 (JP, A) JP-A-2- 141425 (JP, A) (58) Field surveyed (Int. Cl. 7 , DB name) C01G 1/00
Claims (1)
を含む（Bi＋Pb）2Sr2Ca2Cu3Ox構造の110K級酸化物超伝
導体と、（Bi＋Pb）2Sr2Ca1Cu2Ox構造の80K級酸化物超
伝導体から構成され、以下の組成を有する薄膜におい
て、110K級酸化物超伝導体のｃ軸長が3.7100nm以上であ
ることを特徴とする臨界温度が100k以上のBi系超伝導薄
膜。 BiaPbbSr1.00CacCudOx 0.5≦ａ≦1.2 0.0≦ｂ≦1.2 0.4≦ｃ≦1.3 1.3≦ｄ≦2.01. Bi, Pb, Sr, Ca and Cu, or Bi, Sr, Ca and Cu
Is composed of a 110K class oxide superconductor having a (Bi + Pb) 2 Sr 2 Ca 2 Cu 3 O x structure and an 80K class oxide superconductor having a (Bi + Pb) 2 Sr 2 Ca 1 Cu 2 O x structure, A Bi-based superconducting thin film having a critical temperature of 100 k or more, characterized in that the c-axis length of the 110K-class oxide superconductor is 3.7100 nm or more in the thin film having the following composition. Bi a Pb b Sr 1.00 Ca c Cu d O x 0.5 ≦ a ≦ 1.2 0.0 ≦ b ≦ 1.2 0.4 ≦ c ≦ 1.3 1.3 ≦ d ≦ 2.0
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2119235A JP3038485B2 (en) | 1990-05-09 | 1990-05-09 | Bi-based oxide superconducting thin film |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2119235A JP3038485B2 (en) | 1990-05-09 | 1990-05-09 | Bi-based oxide superconducting thin film |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0416592A JPH0416592A (en) | 1992-01-21 |
| JP3038485B2 true JP3038485B2 (en) | 2000-05-08 |
Family
ID=14756310
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2119235A Expired - Lifetime JP3038485B2 (en) | 1990-05-09 | 1990-05-09 | Bi-based oxide superconducting thin film |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3038485B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110777434B (en) * | 2019-11-12 | 2020-07-28 | 中国工程物理研究院化工材料研究所 | Mixed anion infrared nonlinear optical crystal/powder and preparation method thereof |
-
1990
- 1990-05-09 JP JP2119235A patent/JP3038485B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0416592A (en) | 1992-01-21 |
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