According to an embodiment, a superconductor includes a base member, and a superconducting layer provided on the base member. The superconducting Layer has a first surface on the base member side, and a second surface on the side opposite to the first surface. The lattice constant of the base member substantially matches the lattice constant of the superconducting layer. The superconducting layer includes REA.sub.1-xREB.sub.xBa.sub.2Cu.sub.3O.sub.7-z. The x is not less than 0.01 and not more than 0.40. The z is not less than 0.02 and not more than 0.20. The REA includes at least one of Y, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, or Lu. The REB includes at least one of Nd or Sm. The superconducting layer includes a first surface-side region including a portion of the first surface. The first surface-side region includes a first region having an orientation property, and a second region.

An oxide superconductor according to an embodiment includes an oxide superconducting layer includes a single crystal having a continuous perovskite structure containing at least one rare earth element selected from the group consisting of yttrium, lanthanum, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium, barium, and copper, containing praseodymium in a part of the site of the rare earth element in the perovskite structure, and having a molar ratio of praseodymium of 0.00000001 or more and 0.2 or less with respect to the sum of the at least one rare earth element and praseodymium; fluorine in an amount of 2.0×10.sup.15 atoms/cc or more and 5.0×10.sup.19 atoms/cc or less; and carbon in an amount of 1.0×10.sup.17 atoms/cc or more and 5.0×10.sup.20 atoms/cc or less.

A superconductor wire having a first HTS layer with a first cap layer in direct contact with a first surface of the first HTS layer and a second cap layer in direct contact with a second surface of the first HTS layer. There is a first lamination layer affixed to the first cap layer and a stabilizer layer having a first surface affixed to the second cap layer. There is a second HTS layer and a third cap layer in direct contact with a first surface of the second HTS layer and a fourth cap layer in direct contact with a second surface of the second HTS layer. There is a second lamination layer affixed to the fourth cap layer. The second surface of the stabilizer layer is affixed to the third cap layer and there are first and second fillets disposed along a edge of the laminated superconductor.

An oxide superconductor includes: REBa.sub.2Cu.sub.3O.sub.7-x (RE being one element selected from a “RE element group” of Pr, Nd, Sm, Eu, Gd, Y, Tb, Dy, Ho, Er, Tm, Yb, and Lu). The RE includes at least three, types of metallic elements (M1, M2, and M3), and the three types of metallic elements are any element of the RE element group selected in order. In an oxide system satisfying R(1)≦20 mol % and R(M2)≧60 mol % and R(M3)≦20 mol %, R(M1) being an average metallic element ratio of M1 in M1+M2+M3, SD(Ms)>0.15 is satisfied at a position at 50% of an average film thickness of a cross section including the c-axis, Ms being the metallic element of not larger of R(M1) and R(M3), SD(Ms) being a standard deviation/average value of a concentration of Ms.

A superconducting oxide thin film includes a superconducting layer formed on a supporting material. The superconducting layer includes an RE-based superconductor as a main component, and the RE-based superconductor includes a CuO chain that has a Cu vacancy portion.

An oxide superconductor of an embodiment includes an oxide superconductor layer having a continuous Perovskite structure containing rare earth elements, barium (Ba), and copper (Cu). The rare earth elements contain a first element which is praseodymium (Pr), at least one second element selected from the group consisting of neodymium (Nd), samarium (Sm), europium (Eu), and gadolinium (Gd), at least one third element selected from the group consisting of yttrium (Y), terbium (Tb), dysprosium (Dy), and holmium (Ho), and at least one fourth element selected from the group consisting of erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu).

An oxide superconductor of an embodiment includes an oxide superconductor layer having a continuous Perovskite structure including rare earth elements, barium (Ba), and copper (Cu). The rare earth elements include a first element which is praseodymium, at least one second element selected from the group consisting of neodymium, samarium, europium, and gadolinium, at least one third element selected from the group consisting of yttrium, terbium, dysprosium, and holmium, and at least one fourth element selected from the group consisting of erbium, thulium, ytterbium, and lutetium. When the number of atoms of the first element is N(PA), the number of atoms of the second element is N(SA), and the number of atoms of the fourth element is N(CA), 1.5×(N(PA)+N(SA))≤N(CA) or 2×(N(CA)−N(PA))≤N(SA) is satisfied.

According to an embodiment, a superconductor includes a base member, and a superconducting layer provided on the base member. The superconducting layer has a first surface on the base member side, and a second surface on the side opposite to the first surface. The lattice constant of the base member substantially matches the lattice constant of the superconducting layer. The superconducting layer includes REA.sub.1-xREB.sub.xBa.sub.2Cu.sub.3O.sub.7-z. The x is not less than 0.01 and not more than 0.40. The z is not less than 0.02 and not more than 0.20. The REA includes at least one of Y, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, or Lu. The REB includes at least one of Nd or Sm. The superconducting layer includes a first surface-side region including a portion of the first surface. The first surface-side region includes a first region having an orientation property, and a second region.

An oxide superconducting thin film material includes: a metal substrate having a surface with a biaxially oriented crystal orientation structure; an intermediate layer biaxially oriented and formed on the metal substrate; and an oxide superconducting thin film formed on the intermediate layer and composed of a RE123-based oxide superconductor represented by REBa.sub.2Cu.sub.3O.sub.y. The oxide superconducting thin film includes Br (bromine).

An oxide superconductor includes: REBa.sub.2Cu.sub.3O.sub.7-x (RE being one element selected from a “RE element group” of Pr, Nd, Sm, Eu, Gd, Y, Tb, Dy, Ho, Er, Tm, Yb, and Lu). The RE includes at least three types of metallic elements (M1, M2, and M3), and the three types of metallic elements are any element of the RE element group selected in order. In an oxide system satisfying R(M1)≤20 mol % and R(M2)≥60 mol % and R(M3)≤20 mol %, R(M1) being an average metallic element ratio of M1 in M1+M2+M3, SD(Ms)>0.15 is satisfied at a position at 50% of an average film thickness of a cross section including the c-axis, Ms being the metallic element of not larger of R(M1) and R(M3), SD(Ms) being a standard deviation/average value of a concentration of Ms.