A superconducting composition of matter including overlapping first and second regions. The regions comprise unit cells of a solid, the first region comprises an electrical insulator or semiconductor, and the second region comprises a metallic electrical conductor. The second region extends through the solid and a subset of said second region comprise surface metal unit cells that are adjacent to at least one unit cell from the first region. The ratio of the number of said surface metal unit cells to the total number of unit cells in the second region being at least 20 percent.

A superconducting composition of matter including overlapping first and second regions. The regions comprise unit cells of a solid, the first region comprises an electrical insulator or semiconductor, and the second region comprises a metallic electrical conductor. The second region extends through the solid and a subset of said second region comprise surface metal unit cells that are adjacent to at least one unit cell from the first region. The ratio of the number of said surface metal unit cells to the total number of unit cells in the second region being at least 20 percent.

A method of providing an article having a set of directional channels, including a first directional channel, therein is described. The method comprises preparing a mixture including particles comprising a first material and a first binding agent. The method comprises providing an article precursor by surrounding a pattern comprising a second material with the mixture. The method comprises heating the article precursor thereby coalescing the particles to provide the article. The method comprises removing the pattern by reacting the second material to form a gaseous product, thereby providing the set of directional channels in the article, wherein the set of directional channels corresponds with the removed pattern. Such an article is also described.

A method of providing an article having a set of directional channels, including a first directional channel, therein is described. The method comprises preparing a mixture including particles comprising a first material and a first binding agent. The method comprises providing an article precursor by surrounding a pattern comprising a second material with the mixture. The method comprises heating the article precursor thereby coalescing the particles to provide the article. The method comprises removing the pattern by reacting the second material to form a gaseous product, thereby providing the set of directional channels in the article, wherein the set of directional channels corresponds with the removed pattern. Such an article is also described.

A superconducting bulk magnet comprising a plurality of superconducting bulk materials combined, in which breakage of superconducting bulk materials is prevented and a strong magnetic field can be generated, that is, a superconducting bulk magnet comprising a plurality of superconducting bulk materials, each comprising a single-crystal formed RE.sub.1Ba.sub.2Cu.sub.3O.sub.y (RE is one or more elements selected from Y or rare earth elements, where 6.8≦y≦7.1) in which RE.sub.2BaCuO.sub.5 is dispersed and each provided with a top surface, a bottom surface, and side surfaces, combined together, in which superconducting bulk magnet, bulk material units, each comprising a superconducting bulk material and a bulk material reinforcing member arranged so as to cover a side surface of the same, are arranged facing the same direction and contacting each other to form an assembly, a side surface of the assembly is covered by an assembly side surface reinforcing member, a top surface and bottom surface of the assembly are respectively covered by an assembly top reinforcing member and an assembly bottom reinforcing member, and the assembly side surface reinforcing member, the assembly top reinforcing member, and the assembly bottom reinforcing member are joined into an integral unit, is provided.

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.

The invention relates to a material for storing and releasing oxygen, consisting of a reactive ceramic made of copper, manganese and iron oxides, wherein, subject to the oxygen partial pressure of a surrounding atmosphere and/or an ambient temperature, the reactive ceramic has a transition region that can be passed through any number of times, said transition region being between a discharge threshold state of a three-phase crednerite/cuprite/hausmannite mixed ceramic and a charge threshold state of a two-phase spinel/tenorite mixed ceramic. A passing through of the transition region from the discharge threshold state towards the charging threshold state is associated with oxygen uptake and a passing through of the transition region from the charge threshold state towards the discharge threshold state is associated with oxygen release.

The invention relates to a material for storing and releasing oxygen, consisting of a reactive ceramic made of copper, manganese and iron oxides, wherein, subject to the oxygen partial pressure of a surrounding atmosphere and/or an ambient temperature, the reactive ceramic has a transition region that can be passed through any number of times, said transition region being between a discharge threshold state of a three-phase crednerite/cuprite/hausmannite mixed ceramic and a charge threshold state of a two-phase spinel/tenorite mixed ceramic. A passing through of the transition region from the discharge threshold state towards the charging threshold state is associated with oxygen uptake and a passing through of the transition region from the charge threshold state towards the discharge threshold state is associated with oxygen release.

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.