Superconductors, superconducting wires, superconducting bulk magnets, and superconducting coil electromagnets

Abstract

The present invention provides a superconductor which is represented by formula (I) and has a perovskite crystal structure. (I): L(1-x)AxMn(1-y)MyO3 (In the formula (I), L represents one or more elements that are selected from among lanthanoids; A represents one or more elements that are selected from among alkaline earth metals; Mn represents manganese; M represents one or more elements that are selected from among platinum group elements; O represents oxygen; x represents a number of 0 to 1; and y represents a number of 0.01 to 0.5.)

Description

[Technical Field]

[0001] The present invention relates to a superconductor, a superconducting wire, a superconducting bulk magnet, and a superconducting coil electromagnet. This application claims priority based on Japanese Patent Application No. 2022-094963, filed on June 13, 2022, the contents of which are incorporated herein by reference. [Background technology]

[0002] Since the discovery of superconductivity in mercury in 1911, various superconductors have been discovered and put to practical use as superconducting magnets and superconducting quantum interference devices (SQUIDs). In recent years, the superconducting transition temperature (T c ) exceeding 100K has been discovered, increasing the possibility of realizing room-temperature superconductors.

[0003] For example, new superconductors such as iron chalcogenides and nickel oxides have been discovered, expanding the possibilities for substances that can be used as superconducting materials (see, for example, Non-Patent Documents 1 and 2). In addition, copper oxide-based superconductors are also known. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] Iron-Based Layered Superconductor La[O1-xFx]FeAs (x=0.05-0.12) with Tc= 26K, Y.Kamihara et al., J.Am.Chem.Soc. 130, 3296-3297 (2008). [Non-patent document 2] Superconductivity in an infinite-layer nickelate, D.Li et al., Nature 572, 624-628 (2019). Summary of the Invention [Problem to be solved by the invention]

[0005] However, the superconductors in Non-Patent Documents 1 and 2 and the (1111) type copper oxide superconductors all have a layered structure, so the upper critical magnetic field H c2 The anisotropy of the upper critical magnetic field (the magnetic field at which the superconducting state disappears) is strong, and the orientation control of the crystal orientation is necessary when using polycrystals or when thinning the superconductor. Many of the (122) and (11) type copper oxide superconductors do not have a high anisotropy of the upper critical magnetic field, and although such materials do not require orientation control of the crystal orientation, the anisotropy of the upper critical magnetic field under normal pressure is high. c is extremely low, about several tens of Kelvin, for example, about 40 Kelvin, making it difficult to put it to practical use as a superconducting magnet for linear motor cars and the like.

[0006] Therefore, the present invention aims to provide a superconductor with a highly isotropic upper critical magnetic field that does not require crystal orientation control even under normal pressure, as well as a superconducting wire, a superconducting bulk magnet, and a superconducting coil electromagnet that include the same. [Means for solving the problem]

[0007] As a result of extensive research, the inventors discovered that perovskite manganese oxides doped with platinum group elements are new superconductors that exhibit superconductivity under normal pressure. Furthermore, they discovered that these superconductors have isotropy, meaning that the upper critical magnetic field is independent of the magnetic field direction, making it unnecessary to control the crystal orientation, leading to the completion of the present invention. That is, the present invention has the following aspects. [1] A superconductor represented by the following formula (I) and having a perovskite-type crystal structure. L (1-x) A x Mn (1-y) M y O3···(I) [In formula (I), L represents one or more elements selected from lanthanoids, A represents one or more elements selected from alkaline earth metals, Mn represents manganese, M represents one or more elements selected from platinum group elements, O represents oxygen, x is a number of 0 or more and 1 or less, and y is a number of 0.01 or more and 0.5 or less.] [2] The superconductor according to [1], wherein M in the formula (I) is iridium. [3] The superconductor according to [1] or [2], wherein L in the formula (I) is lanthanum. [4] The superconductor according to any one of [1] to [3], wherein A in the formula (I) is strontium. [5] The superconductor according to any one of [1] to [4], which is a bulk body. [6] The superconductor according to any one of [1] to [4], which is a single crystal film. [7] The superconductor according to any one of [1] to [4], which is a polycrystalline film. [8] A superconducting wire comprising the superconductor according to any one of [1] to [7]. [9] A superconducting bulk magnet comprising the superconductor described in [5].

[10] A superconducting coil electromagnet comprising the superconducting wire according to [8]. [Effects of the Invention]

[0008] The superconductor, superconducting wire, superconducting bulk magnet and superconducting coil electromagnet of the present invention have high isotropy and do not require control of the crystal orientation even under normal pressure. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic diagram showing the crystal structure of a superconductor according to one embodiment of the present invention. [Figure 2] 1 is a schematic diagram of a superconductor manufacturing apparatus according to an embodiment of the present invention. [Figure 3] 1 is a schematic diagram of a superconducting wire according to one embodiment of the present invention. [Figure 4] FIG. 4 is a schematic diagram of a superconducting wire according to a modified example of FIG. 3. [Figure 5] 1 is a transmission electron microscope (TEM) photograph of a cross section of a superconductor according to one embodiment of the present invention. [Figure 6] 1 is a photograph showing the results of energy dispersive X-ray analysis (EDX) of a TEM image of a cross section of a superconductor according to one embodiment of the present invention. [Figure 7] 1 is a graph showing the results of the temperature dependence of resistivity of the superconductors according to Examples 1 to 4 and the sample according to Comparative Example 1. [Figure 8] 10 is a graph showing the results of the temperature dependence of resistivity of the superconductors according to Examples 5-1 to 5-6 and the sample according to Comparative Example 2. [Figure 9] 10 is a graph showing the correlation between the lattice volume, the superconducting transition temperature Tc on , and the temperature Tc zero at which the resistivity becomes zero (2×10 −6 [Ω·cm] or less) of the superconductor according to Example 5-3. [Figure 10] 10 is a graph showing the results of the temperature dependence of resistivity of superconductors according to Examples 6-1 and 6-2. [Figure 11] 10 is a graph showing the results of the temperature dependence of resistivity of superconductors according to Examples 7-1 and 7-2. DETAILED DESCRIPTION OF THE INVENTION

[0010] [Superconductors] The superconductor of the present invention is an inorganic oxide represented by the following formula (I) and has a perovskite-type crystal structure. L (1-x) A x Mn (1-y) M y O3···(I) In formula (I), L represents one or more elements selected from lanthanoids. A represents one or more elements selected from alkaline earth metals. Mn represents manganese. M represents one or more elements selected from platinum group elements. O represents oxygen. x is a number between 0 and 1. y is a number between 0.01 and 0.5. In this specification, the term "superconductor" refers to an object that exhibits a phenomenon in which electrical resistance suddenly becomes zero (superconducting transition phenomenon) at extremely low temperatures (for example, 0 to 150 K (-273 to -123°C)). The form of the superconductor is not particularly limited, and examples include a bulk body and thin films such as single crystal films and polycrystalline films.

[0011] In formula (I), L represents one or more elements selected from lanthanoids, which are rare earth elements having atomic numbers 57 to 71, and represent any of lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (TB), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu). As L in formula (I), lanthanum, cerium, praseodymium, neodymium, samarium, europium, and gadolinium are preferred, and lanthanum, cerium, praseodymium, and neodymium are more preferred, and lanthanum is even more preferred, because they form a stable crystal structure. L in formula (I) may be one element or two or more elements.

[0012] In formula (I), A represents one or more elements selected from alkaline earth metals, which are typical elements belonging to Group 2 of the periodic table, and represent any of beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra). As A in formula (I), strontium, calcium, and barium are preferred, and strontium is more preferred, as they form a stable crystal structure. A in formula (I) may be one type of element or two or more types of elements.

[0013] In formula (1), the combination (L,A) of L and A is preferably any one of (La,Sr), (Pr,Sr) and (La,Sr).

[0014] In formula (I), M represents one or more elements selected from the platinum group elements. The platinum group elements are elements located in groups 8 to 10 of the fifth and sixth periods of the periodic table, and represent any of ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), and platinum (Pt). In these elements, the outermost electrons responsible for conduction occupy the 4d orbital or the 5d orbital. M in formula (I) is T c Since this can further increase the Mn site of the superconductor, rhodium, palladium, osmium, iridium, and platinum are preferred, iridium, osmium, and platinum are more preferred, and iridium is particularly preferred. M in formula (I) may be one element or two or more elements. By selecting an element more preferred from the above as an element to substitute for Mn, Mn can be easily substituted at the Mn site of the superconductor. (1-y) M y However, the outermost electrons responsible for conduction are a combination of elements that occupy the 3d orbital and elements that occupy the 5d orbital.

[0015] In formula (I), x represents the ratio of the number of moles of A to the sum of the number of moles of A and the number of moles of L, and is a numerical value between 0 and 1, preferably between 0.1 and 0.9, more preferably between 0.2 and 0.8, and even more preferably between 0.3 and 0.7. When x is within the above numerical range, the superconductor has a more stable crystal structure. Note that when x is 0, the superconductor does not have A in formula (I). When x is 1, the superconductor does not have L in formula (I). x is determined by ICP (Inductively Coupled Plasma) analysis and can be adjusted by the type of L, the type of A, the mixing ratio of L and A, and combinations thereof.

[0016] In formula (I), y represents the ratio of the number of moles of M to the sum of the number of moles of M and the number of moles of Mn, and is a value of 0.01 to 0.5, preferably 0.02 to 0.4, more preferably 0.03 to 0.3 or 0.05 to 0.3, still more preferably 0.2 or less, and particularly preferably 0.15 or less or 0.13 or less. When y is within the above range, the T c Furthermore, it becomes a superconductor that exhibits high isotropy. y is determined by ICP analysis and can be adjusted by the type of M, the mixing ratio of Mn and M, the manufacturing conditions of the superconductor, and a combination of these.

[0017] The superconductor of this embodiment has a perovskite-type crystal structure. As shown in Fig. 1, the superconductor of this embodiment has a cubic unit cell. At each vertex of the cubic crystal, one or more elements selected from L and A (L / A) are located, at the body center, one or more elements selected from Mn and M (Mn / M) are located, and at each face center of the cubic crystal, O (oxygen) is located. In a perovskite crystal structure, the position occupied by an element at each vertex is called the A site, and the position occupied by an element at the body center is called the B site. Compounds having a perovskite crystal structure are generally represented as ABO3, where the element located at the A site is A and the element located at the B site is B. In this embodiment, L / A is located at the A site, and Mn / M is located at the B site.

[0018] The orientation of the octahedron consisting of oxygen and Mn / M is distorted by the interaction with L / A, and the cubic crystal undergoes a phase transition to a less symmetric orthorhombic crystal or a tetragonal crystal.

[0019] T of the superconductor of this embodiment at normal pressure c is, for example, preferably 50 K or higher, more preferably 77 K or higher, and even more preferably 100 K or higher. c If T is equal to or greater than the lower limit, the possibility of practical application of the superconductor as a high-temperature superconductor (for example, a superconductor that exhibits a superconducting transition phenomenon at 77 K or higher) is increased. cThe upper limit is not particularly limited. T of superconductors at normal pressure c can be determined, for example, by measuring the resistivity at cryogenic temperatures. T of superconductors at normal pressure c can be adjusted by the type of L, the type of A, the type of M, the value of x, the value of y, the production conditions of the superconductor, and combinations thereof in formula (I).

[0020] The isotropy parameter γ of the superconductor of this embodiment is, for example, preferably 0.5 to 2.5, more preferably 0.7 to 2.0, and even more preferably 0.9 to 1.5. When the isotropy parameter of the superconductor is within the above numerical range, the isotropy is superior, and it is possible to eliminate the need for orientation control of the crystal orientation with respect to a magnetic field. The isotropy parameters of a superconductor are determined by the upper critical magnetic field H c2 / / and the upper critical magnetic field H in the perpendicular direction c2 ⊥ and the value is calculated by the following formula (2). (Isotropy parameter) = (in-plane upper critical magnetic field (T)) / (out-of-plane upper critical magnetic field (T)) (2) The isotropy parameter of a superconductor can be adjusted by the type of L, the type of A, the type of M, the value of x, the value of y, the manufacturing conditions of the superconductor, and a combination thereof in formula (I).

[0021] Examples of perovskite crystal structures include the (1,1,3) type shown in Figure 1, as well as the (2,1,4) type, (3,2,7) type, and (4,3,10) type. These crystal structures are layered perovskite crystal structures, and all of them can become superconductors, but the (1,1,3) type crystal structure is preferred because it is more stable and has excellent isotropy. Here, the (1,1,3) type indicates that the molar ratio of the element located at the A site to the element located at the B site to oxygen is 1:1:3 (ABO3). Similarly, the (2,1,4) type indicates that the molar ratio of the element located at the A site to the element located at the B site to oxygen is 2:1:4 (ABO4). The (3,2,7) type indicates that the molar ratio of the element located at the A site to the element located at the B site to oxygen is 3:2:7 (ABO7). The (4,3,10) type indicates that the molar ratio of the element located at the A site to the element located at the B site to oxygen is 4:3:10 (ABO). 10 ) In any composition, the ratio of elements in the composition is determined by ICP analysis.

[0022] The (2,1,4) type composition is represented by the following formula (II): L (2-x1) A x1 Mn (1-y1) M y1 O4···(II) In formula (II), the elements L, A and M are the same as the elements L, A and M in the superconductor represented by formula (I).

[0023] In formula (II), x1 represents the ratio of the number of moles of A to the sum of the number of moles of A and the number of moles of L, and is a numerical value of 0 or more and 2 or less, preferably 0.2 or more and 1.8 or less, more preferably 0.4 or more and 1.6 or less, and even more preferably 0.6 or more and 1.4 or less. In formula (II), y1 represents the ratio of the number of moles of M to the sum of the number of moles of M and the number of moles of Mn, and is a numerical value of 0.01 or more and 0.5 or less, preferably 0.02 or more and 0.4 or less, more preferably 0.03 or more and 0.3 or less, or 0.05 or more and 0.3 or less, still more preferably 0.2 or less, and particularly preferably 0.15 or less or 0.13 or less.

[0024] The (3,2,7) type composition is represented by the following formula (III): L (3-x2) A x2 Mn (2-y2) M y2O7···(III) In formula (III), the elements L, A and M are the same as the elements L, A and M in the superconductor represented by formula (I).

[0025] In formula (III), x2 represents the ratio of the number of moles of A to the sum of the number of moles of A and the number of moles of L, and is a numerical value of 0 or more and 3 or less, preferably 0.3 or more and 2.7 or less, more preferably 0.6 or more and 2.4 or less, and even more preferably 0.9 or more and 2.1 or less. In formula (III), y2 represents the ratio of the number of moles of M to the sum of the number of moles of M and the number of moles of Mn, and is a numerical value of 0.02 or more and 1.0 or less, preferably 0.04 or more and 0.8 or less, more preferably 0.06 or more and 0.6 or less, or 0.1 or more and 0.6 or less, still more preferably 0.4 or less, and particularly preferably 0.3 or less or 0.25 or less.

[0026] The (4,3,10) type composition is represented by the following formula (IV): L (4-x3) A x3 Mn (3-y3) M y3 O 10 (IV) In formula (IV), the elements L, A and M are the same as the elements L, A and M in the superconductor represented by formula (I).

[0027] In formula (IV), x3 represents the ratio of the number of moles of A to the sum of the number of moles of A and the number of moles of L, and is a numerical value of 0 or more and 4 or less, preferably 0.4 or more and 3.6 or less, more preferably 0.8 or more and 3.2 or less, and even more preferably 1.2 or more and 2.8 or less. In formula (IV), y3 represents the ratio of the number of moles of M to the sum of the number of moles of M and the number of moles of Mn, and is a numerical value of 0.03 to 1.5, preferably 0.06 to 1.2, more preferably 0.09 to 0.9 or 0.15 to 0.9, still more preferably 0.6 or less, and particularly preferably 0.45 or less or 0.4 or less.

[0028] <Superconductor manufacturing method> The superconductor of this embodiment can be manufactured, for example, by forming a film on a specific substrate. FIG. 2 shows a schematic diagram of the superconductor manufacturing apparatus of this embodiment. As shown in Figure 2, the superconductor manufacturing apparatus 100 of this embodiment includes a galvanometer mirror 1, a film deposition chamber (chamber) 2, and an alloy plate 3 for heating a substrate 5, and two targets TA and TB and the substrate 5 are installed in the film deposition chamber (chamber) 2. The targets TA and TB are set with raw materials having different M concentrations. In this specification, the term "galvanometer mirror" refers to a reflecting mirror that can quickly control a laser beam in any direction and irradiate the laser beam with pinpoint accuracy.

[0029] Examples of raw materials set in targets TA and TB include powders and particles (pellets) of inorganic manganese oxides having L / A, Mn / M, and O. The L / A ratio and Mn / M ratio can be set arbitrarily depending on the performance of the desired superconductor.

[0030] As L in the raw material, for example, lanthanum, cerium, praseodymium, neodymium, samarium, europium, and gadolinium are preferred, lanthanum, cerium, praseodymium, and neodymium are more preferred, and lanthanum is even more preferred, as they have a stable crystal structure. As A in the raw material, for example, strontium, calcium, and barium are preferable, and strontium is more preferable, since they form a stable crystal structure. The L / A combination in the raw material is preferably any one of La / Sr, Pr / Sr and La / Sr.

[0031] As for M in raw materials, T c For example, iridium, osmium, and platinum are preferred, and iridium is more preferred, since they can further increase the sensitivity.

[0032] A method for manufacturing a superconductor using the manufacturing apparatus shown in FIG. 2 (galvano scanning pulsed laser deposition method) will be described. First, an excimer laser or a solid-state laser is irradiated onto the galvanometer mirror 1, and the reflected light is irradiated onto the targets TA and TB. Examples of excimer lasers include argon fluorine (ArF) excimer lasers (oscillation wavelength 193 nm), krypton fluorine (KrF) excimer lasers (oscillation wavelength 248 nm), xenon chlorine (XeCl) excimer lasers (oscillation wavelength 308 nm), and xenon fluorine (XeF) excimer lasers (oscillation wavelength 351 nm). As the excimer laser, an ArF excimer laser, a KrF excimer laser, a XeCl excimer laser, and a XeF excimer laser are preferred, as they are likely to promote the release of atoms of the raw material, and a KrF excimer laser is more preferred. An example of a solid-state laser is a neodymium-doped yttrium aluminum garnet (Nd:YAG) laser (fourth harmonic oscillation wavelength: 266 nm).

[0033] The atoms of the raw material emitted by the excimer laser or solid-state laser reach the surface of the substrate 5, and by continuing to irradiate the excimer laser or solid-state laser, a thin film is formed on the surface of the substrate 5. The thin film may be a single-crystal film made of a single crystal, or a polycrystalline film made of a combination of two or more types of crystals. As the thin film, a polycrystalline film is preferred because it has better industrial applicability.

[0034] The thickness of the superconductor thin film is, for example, preferably 10 to 200 nm, more preferably 50 to 170 nm, and even more preferably 100 to 150 nm. When the thickness is equal to or greater than the lower limit, the isotropy of the superconductor can be further improved. When the thickness is equal to or less than the upper limit, the physical strength of the superconductor can be further improved. The thickness of the superconductor thin film can be determined, for example, by observing the cross section of the thin film in the thickness direction with an electron microscope.

[0035] Examples of the substrate 5 include an LSAT substrate, an STO substrate, an LAO substrate, a DSO substrate, an LSAO substrate, an NGO substrate, a KTO substrate, and an MgO substrate. The LSAT substrate is a substrate made of a metal oxide containing lanthanum, aluminum, strontium, and tantalum as elements. The STO substrate is a substrate made of a metal oxide containing strontium and titanium as elements. The LAO substrate is a substrate made of a metal oxide containing lanthanum and aluminum as elements. The DSO substrate is a substrate made of a metal oxide containing dysprosium and scandium as elements. The LSAO substrate is a substrate made of a metal oxide containing lanthanum, strontium, and aluminum as elements. The NGO substrate is a substrate made of a metal oxide containing neodymium and gallium as elements. The KTO substrate is a substrate made of a metal oxide containing potassium and tantalum as elements. The MgO substrate is a substrate made of a metal oxide containing magnesium as an element. The substrate 5 is preferably an LSAT substrate because it is easy to obtain a superconductor having a stable crystal structure, and it is preferable to use an LSAT substrate or an STO substrate because it is easy to obtain a superconductor having a high superconducting transition temperature at normal pressure.

[0036] When depositing a superconductor film, it is preferable to do so while supplying oxygen gas to the film deposition chamber 2. By depositing a superconductor film while supplying oxygen gas to the film deposition chamber 2, oxygen is sufficiently bonded, and a superconductor having a more stable crystal structure can be obtained. The partial pressure of the oxygen gas supplied to the film deposition chamber 2 is, for example, preferably 1 to 1000 mTorr (0.13 to 133.3 Pa), more preferably 10 to 500 mTorr (1.3 to 66.7 Pa), and even more preferably 20 to 100 mTorr (2.7 to 13.3 Pa). When the partial pressure of the oxygen gas supplied to the film deposition chamber 2 is equal to or higher than the above lower limit, sufficient oxygen is bonded, resulting in a superconductor with a more stable crystal structure. When the partial pressure of the oxygen gas supplied to the film deposition chamber 2 is equal to or lower than the above upper limit, the supply of more oxygen than necessary can be suppressed, and the amount of oxygen used can be reduced. The partial pressure of the oxygen gas supplied to the film deposition chamber 2 can be determined, for example, from a pressure gauge attached to the oxygen cylinder.

[0037] The time required to form a film of a superconductor (film formation time) is, for example, preferably 10 to 150 minutes, more preferably 60 to 120 minutes, and even more preferably 90 to 110 minutes. When the film formation time is equal to or greater than the above lower limit, a thin film of sufficient thickness can be obtained. When the film formation time is equal to or less than the above upper limit, productivity of the superconductor can be further improved. Here, the film formation time refers to the time from the start of irradiation with an excimer laser or solid-state laser to the end of irradiation.

[0038] The temperature of the substrate 5 when depositing a superconductor film (film deposition temperature) is, for example, preferably 650 to 1000 K, more preferably 700 to 900 K, and even more preferably 750 to 810 K. When the film deposition temperature is within the above numerical range, a superconductor having a more stable crystal structure can be obtained.

[0039] For example, as shown in Fig. 2, an alloy plate 3 for heating the substrate 5 is placed on the back side of the film-forming surface of the substrate 5, and an infrared (IR) laser for heating the substrate is irradiated onto the alloy plate 3, causing the alloy plate 3 to absorb the infrared light, thereby heating the substrate 5 to a desired film-forming temperature. The film-forming temperature can be adjusted by the irradiation intensity and irradiation time of the IR laser, etc. The alloy plate 3 may be, for example, a plate made by processing a nickel alloy such as Inconel (registered trademark). The method for heating the substrate 5 is not limited to the method using an IR laser, but may also be a method using an electric heating wire or a method using a lamp (such as an infrared radiation lamp).

[0040] The pressure in the film deposition chamber 2 when depositing a superconductor film (film deposition pressure) is, for example, preferably 1 to 1000 mTorr (0.13 to 133.3 Pa), more preferably 10 to 500 mTorr (1.3 to 66.7 Pa), and even more preferably 20 to 100 mTorr (2.7 to 13.3 Pa). When the film deposition pressure is within the above numerical range, a superconductor having a more stable crystal structure can be obtained.

[0041] The use of the galvanometer mirror 1 makes it possible to selectively strike the targets TA and TB at high speed, which makes it easy to adjust the ratio of Mn / M (y in formula (I)) and shortens the film deposition time. The superconductor may be deposited by directly irradiating a pulsed laser (excimer laser or solid-state laser) onto a target without using the galvanometer mirror 1 (pulse laser deposition method).

[0042] 2 shows an example in which raw materials with different compositions are set as two targets TA and TB, and the example in which reflected light is separately irradiated onto the two targets TA and TB has been described above, but the present invention is not limited to the above example. That is, in this embodiment, a superconductor may be formed by setting one type of raw material as one target and irradiating the one target with a pulsed laser or reflected light. That is, in the method for producing a superconductor according to this embodiment, one or more types of raw materials are set as targets, and the one or more types of targets are irradiated with a pulsed laser or reflected light.

[0043] The superconductor may be a bulk material instead of a thin film. This makes it easier to apply it to superconducting magnets, which will be described later. Furthermore, the above-mentioned thin film can be manufactured using the bulk material as a raw material. In this specification, the term "bulk body" refers to a sintered body or a melt-grown body such as a ceramic. The bulk body can be obtained, for example, by sintering a mixture of powders and other raw materials for the thin film. Specifically, in the case of Ir-doped LaSrMnO (LaSrMnIrO), the raw material powders of lanthanum oxide (LaO), strontium carbonate (SrCO), manganese dioxide (MnO), and iridium oxide (IrO) are weighed out to a stoichiometric ratio, thoroughly mixed in a mortar, and then compressed under a pressure of 40 to 50 MPa in a press to form pellets. The mixture is then fired in an electric furnace at 1050 to 1150°C for 12 hours, crushed, and re-formed into pellets, which are then fired at 1150 to 1250°C for 24 hours. Alternatively, the bulk body can be produced by, for example, the floating zone method (FZ method). In particular, the FZ method is preferred for producing single-crystal bulk bodies. The FZ method involves heating a portion of a polycrystalline sample rod, which serves as the raw material, to create a molten zone between the sample rod and the lower single crystal, which serves as the seed crystal. The entire molten zone is then moved downward, and the molten zone is cooled to obtain a single crystal.

[0044] [Superconducting wire] The superconducting wire of the present invention includes the superconductor of the present invention. An example of a superconducting wire is a wire in which the superconductor of the present invention is used as the superconducting layer of the superconducting wire. Fig. 3 is a schematic diagram of a superconducting wire according to one embodiment of the present invention, and Fig. 4 is a schematic diagram of a superconducting wire according to a modification of Fig. 3. A superconducting wire 20A shown in Fig. 3 includes a substrate 5 and a superconducting layer 10 formed in contact with the upper surface of the substrate 5. A superconducting wire 20B shown in Fig. 4 includes a substrate 5, an intermediate layer 6 formed above the substrate 5, and a superconducting layer 10 formed in contact with the upper surface of the intermediate layer 6.

[0045] Normally, the orientation of the superconducting layer of superconducting wire must be controlled during the manufacturing process. For example, the orientation of the superconducting layer can be controlled by rolling the material while it is heated, or by precipitating the superconductor from a molten state. In particular, a method of forming an intermediate layer between the substrate and the superconducting layer to control the orientation of the superconducting layer is often used. The structure of superconducting wire manufactured by this method is as shown in Figure 4.

[0046] However, when the superconductor of the present invention is used as the superconducting layer, orientation control is not necessary. For example, when the superconductor of the present invention is used as the superconducting layer, the superconducting wire of the present invention does not require an intermediate layer. That is, it is possible to produce a superconducting wire having a structure as shown in FIG. 3. Therefore, the manufacturing process of the superconducting wire can be simplified and raw material costs can be reduced. The superconducting wire of the present invention may also have an intermediate layer. Superconducting wires are expected to be used in power transmission lines and other applications that can reduce electrical losses during power transmission.

[0047] [Superconducting bulk magnets] The superconducting bulk magnet of the present invention includes the superconductor of the present invention in bulk form. An example of a superconducting bulk magnet is a magnet made by sintering raw materials that form a polycrystalline film and molding it into a disk shape. Superconducting bulk magnets are expected to be used in magnetic separation devices, flywheel-type energy storage devices, and ultra-powerful motors.

[0048] [Superconducting coil electromagnet] The superconducting coil electromagnet of the present invention includes the superconducting wire of the present invention. An example of a superconducting coil electromagnet is an electromagnet formed by forming a superconducting wire into a coil shape. Superconducting coil electromagnets are expected to be applied to nuclear magnetic resonance spectroscopy (NMR) that does not use liquid helium, nuclear magnetic resonance imaging (MRI) that does not use liquid helium, and magnetic levitation railways such as linear motor cars.

[0049] The superconductor of this embodiment has a perovskite-type crystal structure in which a portion of manganese is replaced with a platinum group element, and therefore has isotropy and does not require orientation control of the crystal orientation with respect to a magnetic field. In the superconductor of this embodiment, the ratio of the number of moles of the platinum group element to the sum of the number of moles of the platinum group element and the number of moles of Mn is 0.01 or more and 0.5 or less. c This further increases the usability as a high-temperature superconductor. The superconducting wire of this embodiment uses the superconductor of this embodiment, and therefore does not require control of the crystal orientation relative to a magnetic field, further increasing the possibility of practical application. The superconducting bulk magnet of this embodiment uses the superconductor of this embodiment, and therefore does not require orientation control of the crystal orientation relative to the magnetic field, further increasing the possibility of practical application. The superconducting coil electromagnet of this embodiment uses the superconductor of this embodiment, and therefore does not require control of the crystal orientation relative to the magnetic field, further increasing the possibility of practical application. [Example]

[0050] The present invention will be described in more detail below using examples, but the present invention is not limited to these examples.

[0051] [Example 1] As a raw material for the superconductor, a pellet-shaped manganese oxide having the formula (I) of L=La, A=Sr, M=Ir, x=0.3, and y=0 was used and set as a target TA. 0.7 Sr 0.3 Similarly, a pellet-shaped manganese oxide having the composition formula (I) of L=La, A=Sr, M=Ir, x=0.3, and y=0.05 was used as the target TB. 0.7 Sr 0.3 Mn 0.95 Ir 0.05 The composition represented by O3 was set.

[0052] Under normal pressure and in an environment of 25°C, a KrF excimer laser (oscillation wavelength 248 nm) was irradiated onto the galvanometer mirror for 100 minutes, and the laser was fired at high speed at the targets TA and TB, respectively, to form a thin film (single crystal film, thickness 150 nm) with the number of moles of iridium relative to the total number of moles of manganese and iridium (hereinafter also referred to as the iridium concentration) adjusted to 1.8% by galvanometer scanning pulsed laser deposition (epitaxial growth).

[0053] The substrate for film formation is (LaAlO3) 0.3 -(SrAl 0.5 Ta 0.5 O3) 0.7 A c-plane LSAT substrate with the above composition was used, and oxygen gas at 50 mTorr (6.7 Pa) was supplied to the deposition chamber during deposition. During deposition, a nickel alloy plate was placed on the surface of the LSAT substrate opposite to the deposition surface, and the LSAT substrate was indirectly heated by irradiating this alloy plate with an 18 W IR laser. The surface temperature of the LSAT substrate during deposition was 530°C.

[0054] [Example 2] As the raw material for the superconductor, a pellet-shaped manganese oxide having y = 0.05 in formula (I) was used as the target TA, and a pellet-shaped manganese oxide having y = 0.21 in formula (I) was used as the target TB. Except for this, a thin film (single crystal film, thickness 130 nm) with an iridium concentration adjusted to 7.3% was deposited in the same manner as in Example 1. That is, in Example 2, a pellet-shaped manganese oxide having the composition formula La 0.7 Sr 0.3 Mn 0.95 Ir 0.05 The composition represented by O3 was set, and the target TB was set to the composition formula La 0.7 Sr 0.3 Mn 0.79 Ir 0.21 The composition represented by O3 was set.

[0055] [Example 3] As a raw material for the superconductor, a pellet-shaped manganese oxide with y = 0.11 in formula (I) was used and set as target TA, and no raw material was set in target TB, and no separate irradiation was performed on targets TA and TB. In the same manner as in Example 1, a thin film (single crystal film, thickness 120 nm) with an iridium concentration adjusted to 11.0% was deposited. That is, in Example 3, a manganese oxide pellet with the composition formula La 0.7 Sr 0.3 Mn 0.89 Ir 0.11 A composition represented by O3 was set, and only the target TA was irradiated with a KrF excimer laser.

[0056] [Example 4] As a raw material for the superconductor, a pellet-shaped manganese oxide with y = 0.23 in formula (I) was used and set as target TA, and no raw material was set in target TB, and no separate irradiation was performed on targets TA and TB. In the same manner as in Example 1, a thin film (single crystal film, thickness 150 nm) with an iridium concentration adjusted to 19.3% was deposited. That is, in Example 4, a manganese oxide pellet with the composition formula La 0.7 Sr 0.3 Mn 0.77 Ir 0.23 A composition represented by O3 was set, and only the target TA was irradiated with a KrF excimer laser.

[0057] [Comparative Example 1] As a raw material for the superconductor, a pellet-shaped manganese oxide with y = 0 in formula (I) was used and set as target TA, and no raw material was set in target TB, and targets TA and TB were not separately bombarded. In the same manner as in Example 1, a thin film (single crystal film, thickness 130 nm) with an iridium concentration adjusted to 0% was deposited. That is, in Comparative Example 1, a manganese oxide pellet with y = 0 in formula (I) was used as target TA, and a raw material was not set in target TB, and targets TA and TB were not separately bombarded. 0.7 Sr 0.3 A composition represented by MnO3 was set, and only the target TA was irradiated with a KrF excimer laser.

[0058] (ICP analysis) To determine y in formula (I), ICP analysis was performed on the samples of Examples 1 to 4 and Comparative Example 1 under the following conditions. As a result, y = 0.018, 0.073, 0.11, and 0.193 were found for Examples 1, 2, 3, and 4, respectively. Furthermore, when x in formula (I) was determined by ICP analysis for the sample of Example 3, it was found to be 0.30. That is, in Example 3 above, which used a manganese oxide with an A-site composition ratio of La:Sr = 7:3 as the target, it was confirmed that the Sr concentration in the A-site was 30%.

[0059] (TEM observation) The cross section of the obtained thin film of Example 2 (iridium concentration 7.3%) was observed by TEM. The TEM image is shown in Fig. 5, and the EDX image of the TEM image is shown in Fig. 6. In Fig. 5, the crystal structure of the unit cell of the superconductor of Example 2 is also shown in the upper right corner of the figure, and La or Sr atoms and O atoms are shown in the TEM image. As shown in Figure 5, it was confirmed that a thin film of LaSrMnO containing iridium (Ir:LSMO thin film) was regularly formed on the LSAT substrate. As shown in Figure 6, it was confirmed that a portion of the manganese located at the body center was replaced by iridium.

[0060] (Resistivity measurement) The resistivity of each thin film was measured by passing a current of 1000 μA through it while lowering the temperature using liquid helium under atmospheric pressure. The results are shown in Figure 7. 7, the thin film of Comparative Example 1 (iridium concentration 0%) did not exhibit a superconducting transition phenomenon, which confirmed that the thin film of Comparative Example 1 cannot be said to be a superconductor.

[0061] In the thin films of Examples 1 to 4 (iridium concentrations of 1.8%, 7.3%, 11.0%, and 19.3%), a phenomenon in which the resistivity rapidly approaches zero (superconducting transition phenomenon) was confirmed as the temperature was decreased. This confirmed that the thin films of Examples 1 to 4 function as superconductors.

[0062] As shown in Figure 7, the superconducting transition temperature (T c ) was the highest in the thin film of Example 3 (iridium concentration 11.0%), at approximately 123 K. In the thin film of Example 1 (iridium concentration 1.8%), T c is about 9K, and in the thin film of Example 2, T c is about 83K, and in the thin film of Example 4 (iridium concentration 19.3%), T c It was confirmed that the values ​​were approximately 67K.

[0063] For each thin film, the superconducting transition temperature (T c on), and the resistivity is zero (2×10 -6 [Ω·cm] or less) (hereinafter referred to as "T c zero "), the upper critical magnetic field in the in-plane direction (hereinafter referred to as "μ0H c2 / / (0)), the upper critical magnetic field in the perpendicular direction (hereinafter referred to as "μ0H c2 ⊥ Since a c-plane LSAT substrate was used as the substrate, the upper critical magnetic field in the in-plane direction was measured as the upper critical magnetic field μ0H in the direction parallel to the c-plane. c2 ||ab (0), the upper critical magnetic field in the perpendicular direction is the upper critical magnetic field μ0H in the c-axis direction. c2 ||c Corresponds to (0). μ0H c2 / / (0) and μ0H c2 ⊥ The isotropy parameter was calculated from the value of (0) based on the following formula (3). The results are shown in Figure 8. In Figure 8, "-" indicates that T c zero indicates that no (Isotropic parameter) = (μH c2 / / (0)) / (μ0H c2 ⊥ (0)) ···(3) In equation (3), μ0 represents the vacuum permeability, and H c2 represents the magnitude of the upper critical magnetic field. Data marked with a "-" in the table are data that were not measured.

[0064] [Table 1]

[0065] As shown in Table 1, the thin films of Examples 1 to 4 had isotropy parameter values ​​of 0.96 to 2.0, which were close to 1, confirming excellent isotropy. The thin films of Examples 1 to 3 had isotropy parameter values ​​of 0.96 to 1.3, confirming particularly excellent isotropy. Furthermore, in the compositions of Examples 1 to 4 in which the composition is (La,Sr) and the B site is (Mn,Ir), it is considered that in formula (I), y is preferably 0.02 or more and 0.2 or less, more preferably 0.02 or more and 0.15 or less, and even more preferably 0.05 or more and 0.13 or less. It should be noted that the upper critical magnetic field could not be measured because the superconducting transition phenomenon could not be observed for the thin film of Comparative Example 1. Therefore, the isotropy parameter for the thin film of Comparative Example 1 could not be calculated.

[0066] [Example 5-1] The only target TA is the one with the formula Pr 0.7 Sr 0.3 Mn 0.90 Ir 0.10 The composition represented by O3 was set.

[0067] Under normal pressure and at 25°C, a KrF excimer laser (oscillation wavelength 248 nm) was irradiated via a galvanometer mirror onto the target TA alone for 100 minutes, and a thin film (single crystal film) with an iridium concentration adjusted to 6.8% was deposited (epitaxial growth) using the galvanometer scanning pulsed laser deposition method.

[0068] The substrate for film formation is (LaAlO3) 0.3 -(SrAl 0.5 Ta 0.5 O3) 0.7 A c-plane LSAT substrate having the above composition was used, and oxygen gas at 50 mTorr (6.7 Pa) was supplied to the deposition chamber during deposition. During deposition, a nickel alloy plate was placed on the surface of the LSAT substrate opposite to the deposition surface, and the LSAT substrate was indirectly heated by irradiating this alloy plate with an 18 W IR laser. The surface temperature of the LSAT substrate during deposition was 530°C.

[0069] [Examples 5-2 to 5-6] A thin film was formed in the same manner as in Example 5-1, except that the composition ratio of the composition set as the target TA was changed.

[0070] Comparative Example 2 As a raw material for superconductors, the target TA has the composition formula Pr 0.7 Sr 0.3 A composition represented by MnO3 was set, and a thin film (single crystal film) with an iridium concentration adjusted to 0% was formed in the same manner as in Example 5-1. That is, in Comparative Example 2, only the target TA was irradiated with a KrF excimer laser.

[0071] (ICP analysis) In order to determine x and y in formula (I), ICP analysis was carried out on the samples of Examples 5-1 to 5-6 under the same conditions as in Examples 1 to 4.

[0072] In addition, the lattice constants a and c measured by X-ray diffraction (XRD) using CuKα1 radiation were used to calculate the formula V = a 2 The lattice volume V was calculated by × c.

[0073] (Resistivity measurement) The resistivity was measured while decreasing the temperature for the thin films of Examples 5-1 to 5-6 and Comparative Example 2 under the same conditions as in Example 1. The results are shown in FIG. As shown in FIG. 8, the thin film of Comparative Example 2 (iridium concentration 0%) did not exhibit a superconducting transition phenomenon.

[0074] The thin films of Examples 5-1 to 5-6 (iridium concentrations of 6.8%, 6.9%, 7.1%, 8.1%, 11.9%, and 17.5%) were confirmed to exhibit a superconducting transition phenomenon. This confirmed that the thin films of Examples 5-1 to 5-6 function as superconductors.

[0075] As shown in Figure 8, the superconducting transition temperature (T c) was the highest in the thin film of Example 5-1 (iridium concentration 6.8%), at approximately 119 K. 0.7 Sr 0.3 For )(Mn,Ir)O3, the superconducting transition temperatures are summarized in Table 2.

[0076] In addition, for each thin film, T c on , T c zero , μ0H c2 / / (0), μ0H c2 ⊥ (0) were measured. c2 / / (0) to μ0H c2 ⊥ The isotropy parameter was calculated by dividing by (0). The results are also summarized in Table 2. In all of Examples 5-1 to 5-6, the unit cell has a cubic crystal structure, and therefore it is believed that even samples for which the isotropy parameter was not measured exhibit high isotropy.

[0077] FIG. 9 shows the relationship between the lattice volume and T c on and T c zero 9 is a graph showing the correlation between the lattice volume and the lattice constants. In the figure, the measurement results of Comparative Example 2, Example 5-4, Example 5-5, Example 5-1, Example 5-2, Example 5-3, and Example 5-6 are plotted in order of increasing lattice volume. FIG. 9 was calculated from the lattice constants obtained by ICP analysis. From FIG. 9, it can be seen that Example 5-1 has a lattice volume of 58.5 Å. 3 With increasing lattice volume, T c on and T c zero It was confirmed that the lattice volume V increased. The lattice volume V is also shown in Table 2. The lattice volume of Comparative Example 2 was 57.78 Å. 3Therefore, it is considered preferable that the ratio of the lattice volume of the superconductor after Ir substitution to the lattice volume of the composition (Comparative Example 2) not substituted with Ir element is 1.003 times or more and 1.017 times or less in the superconductor according to this embodiment. Data marked with the symbol "-" in the table is data that was not measured. From Table 2, when the A site is (Pr, Sr) and the B site is (Mn, Ir), it is considered that y in formula (I), which corresponds to the Ir concentration, is preferably 0.05 or more and 0.1 or less, and more preferably 0.06 or more and 0.075 or less, from the viewpoint of the transition temperature.

[0078] [Table 2]

[0079] [Example 6-1] As a raw material for superconductors, the only target TA is Nd 0.7 Sr 0.3 Mn 0.90 Ir 0.10 The composition represented by O3 was set.

[0080] Under normal pressure and at 25°C, a KrF excimer laser (oscillation wavelength 248 nm) was irradiated via a galvanometer mirror onto the target TA alone for 100 minutes, and a thin film (single crystal film, thickness 90 nm) with an iridium concentration adjusted to 7.9% was deposited (epitaxial growth) using the galvanometer scanning pulsed laser deposition method.

[0081] The substrate for film formation is (LaAlO3) 0.3 -(SrAl 0.5 Ta 0.5 O3) 0.7 A c-plane LSAT substrate with the above composition was used, and oxygen gas at 50 mTorr (6.7 Pa) was supplied to the deposition chamber during deposition. During deposition, a nickel alloy plate was placed on the surface of the LSAT substrate opposite to the deposition surface, and the LSAT substrate was indirectly heated by irradiating this alloy plate with an 18 W IR laser. The surface temperature of the LSAT substrate during deposition was 530°C.

[0082] [Example 6-2] A thin film (single crystal film, thickness 80 nm) was formed in the same manner as in Example 6-1, except that the composition ratio in the target composition was changed, with the iridium concentration adjusted to 11%.

[0083] (ICP analysis) To determine x and y in formula (I), ICP analysis was performed on the samples of Examples 6-1 and 6-2 under the same conditions as in Examples 1 to 4. As a result, x = 0.315 and y = 0.079 in Example 6-1, and y = 0.115 in Example 6-2.

[0084] (Resistivity measurement) The resistivity of the thin films of Examples 6-1 and 6-2 was measured while decreasing the temperature under the same conditions as in Example 1. The results are shown in FIG.

[0085] The superconducting transition phenomenon was confirmed in the thin films of Examples 6-1 and 6-2 (iridium concentrations of 7.9% and 11.5%).

[0086] As shown in Figure 10, the superconducting transition temperature (T c ) was the highest in the thin film of Example 6-2 (iridium concentration 11.5%), at approximately 98 K. The superconducting transition temperatures are summarized in Table 3.

[0087] In addition, for each thin film, V, T c on , T c zero The lattice volume V was calculated by determining the lattice constants a and c in the same manner as in Example 5-1, and then calculating V=a 2 × c. 0.7 Sr 0.3 The results for (Mn,Ir)O3 are also summarized in Table 3. Data marked with a "-" in the table are data that were not measured.

[0088] [Table 3]

[0089] [Example 7-1] As a raw material for superconductors, only one target TA is used, and the composition formula is La 0.7 Sr 0.3 Mn 0.95 Ir 0.05 The composition represented by O3 was set.

[0090] Under normal pressure and at 25°C, a KrF excimer laser (oscillation wavelength 248 nm) was irradiated via a galvanometer mirror onto the target TA alone for 100 minutes, and a thin film (single crystal film, thickness 70 nm) with an iridium concentration adjusted to 3.6% was deposited (epitaxial growth) using the galvanometer scanning pulsed laser deposition method.

[0091] The substrate used for film deposition was a c-plane STO substrate with a composition of SrTiO3. Oxygen gas at 50 mTorr (6.7 Pa) was supplied to the deposition chamber during deposition. A nickel alloy plate was placed on the side of the STO substrate opposite the deposition surface, and an 18 W IR laser was irradiated onto this alloy plate to indirectly heat the STO substrate. The surface temperature of the STO substrate during deposition was 530°C.

[0092] [Example 7-2] The target TA is composed of La 0.7 Sr 0.3 Mn 0.90 Ir 0.10 A thin film (single crystal film, thickness 60 nm) with an iridium concentration adjusted to 8.8% was formed in the same manner as in Example 7-1, except that the composition represented by O3 was used.

[0093] Comparative Example 3 As a raw material for superconductors, the target TA has the composition formula La 0.7 Sr 0.3 A thin film (single crystal film, thickness 70 nm) was formed in the same manner as in Example 7-1, except that a composition represented by MnO3 was used, and the iridium concentration was adjusted to 0%.

[0094] (ICP analysis) In order to determine x and y in formula (I) and the lattice constants a and c of the superconductor constituting the thin film, ICP analysis was performed on the samples of Example 7-1 and Example 7-2 under the same conditions as in Examples 1 to 4. As a result, y = 0.036 in Example 7-1 and y = 0.088 in Example 7-2. In addition, from the lattice constants a and c measured in the same manner as in the above example, the formula V = a 2 The lattice volume V was calculated by multiplying the lattice constants by 1 / 2 and the lattice constants by 1 / 2. The lattice volume V of Comparative Example 3 was 58.73 Å. 3 It was.

[0095] (Resistivity measurement) The resistivity of the thin films of Examples 7-1 and 7-2 was measured while decreasing the temperature under the same conditions as in Example 1. The results are shown in FIG.

[0096] The superconducting transition phenomenon was confirmed in the thin films of Examples 7-1 and 7-2 (iridium concentrations of 3.6% and 8.8%).

[0097] In addition, for each thin film, T c on , T c zero , μ0H c2 / / (0), μ0H c2 ⊥ (0), V were measured. c2 / / (0) to μ0H c2 ⊥ The isotropy parameter was calculated by dividing by (0). 0.7 Sr 0.3 The results for (Mn,Ir)O3 are summarized in Table 4. Data marked with a "-" in the table are data that were not measured.

[0098] [Table 4]

[0099] As described above, it has been found that the superconductor of the present invention has excellent isotropy and does not require orientation control of the crystal orientation with respect to a magnetic field. According to the superconductor of the present invention, T c It was found that this has a high potential for practical application as a high-temperature superconductor.

Claims

1. A superconductor which is a polycrystalline film represented by formula (I) and has a perovskite-type crystal structure. L （１－ｘ） A ｘ Mn （１－ｙ） M ｙ O ３ ・・・(I) [In formula (I), L represents one or more elements selected from lanthanoids, A represents one or more elements selected from alkaline earth metals, Mn represents manganese, M represents one or more elements selected from platinum group elements, O represents oxygen, x is a number of 0 or more and 1 or less, and y is a number of 0.01 or more and 0.5 or less.]

2. 2. The superconductor of claim 1, wherein M in formula (I) is iridium.

3. 3. The superconductor according to claim 1, wherein L in formula (I) is lanthanum.

4. 3. The superconductor according to claim 1, wherein A in formula (I) is strontium.

5. A superconducting wire containing a superconductor represented by formula (I) and having a perovskite-type crystal structure. L （１－ｘ） A ｘ Mn （１－ｙ） M ｙ O ３ ・・・(I) [In formula (I), L represents one or more elements selected from lanthanoids, A represents one or more elements selected from alkaline earth metals, Mn represents manganese, M represents one or more elements selected from platinum group elements, O represents oxygen, x is a number of 0 or more and 1 or less, and y is a number of 0.01 or more and 0.5 or less.]

6. A superconducting wire as described in claim 5, wherein the superconductor is either a bulk body, a single crystal film, or a polycrystalline film.

7. 6. The superconducting wire according to claim 5, wherein M in formula (I) is iridium.

8. 6. The superconducting wire according to claim 5, wherein L in formula (I) is lanthanum.

9. 6. The superconducting wire according to claim 5, wherein A in formula (I) is strontium.

10. A superconducting coil electromagnet comprising the superconducting wire according to any one of claims 5 to 9.

11. A superconducting bulk magnet comprising a bulk superconductor represented by formula (I) and having a perovskite-type crystal structure. L （１－ｘ） A ｘ Mn （１－ｙ） M ｙ O ３ ・・・(I) [In formula (I), L represents one or more elements selected from lanthanoids, A represents one or more elements selected from alkaline earth metals, Mn represents manganese, M represents one or more elements selected from platinum group elements, O represents oxygen, x is a number of 0 or more and 1 or less, and y is a number of 0.01 or more and 0.5 or less.]

12. 12. The superconducting bulk magnet of claim 11, wherein M in formula (I) is iridium.

13. 12. The superconducting bulk magnet of claim 11, wherein L in formula (I) is lanthanum.

14. 12. The superconducting bulk magnet of claim 11, wherein A in formula (I) is strontium.

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