Materials, devices, and methods for producing strong magnetic-flux pinning in superconducting materials by including sites having high electronic effective mass and charge carrier density

A superconducting material having a strong magnetic-flux pinning by way of sites having high electronic effective mass and charge carrier density. The superconducting material involves a superconducting host material and a dopant pinning material being inert in relation to the superconducting host material and has a √{square root over (ρ)}/m* in a range less than that of the superconducting host material, the dopant pinning material doping the superconducting host material.

BACKGROUND OF THE INVENTION

Technical Field

The present disclosure technically relates to superconducting materials. Particularly, the present disclosure technically relates to superconducting materials having a strong magnetic flux pinning.

Description of Related Art

Flux-Pinning is generally defined as the phenomenon where a magnet's lines of force (called flux) become trapped or “pinned” inside a superconducting material. This pinning binds the superconductor to the magnet at a fixed distance. Flux-pinning is only possible when there are defects in the crystalline structure of the superconductor—usually resulting from grain boundaries or impurities. In the related art, large and randomly arranged pinning centers (single-particle) have been observed to cause a strong deformation of a flux line lattice, wherein each pinning center acts on the lattice with a maximum force, in relation to superconductors. The average force for such pinning is inferable from a simple summing procedure. Pinning centers of average force, such as clusters of dislocations, strongly deform the flux line lattice only in weak fields and in fields close to the critical field, wherein a peak exists in the dependence of the critical current on magnetic field. In a range of intermediate fields, a weak collective pinning exists. A large concentration of weak centers results in collective pinning in all fields, wherein, near the critical field, a critical current peak is observed.

Challenges experienced in the related art of high-temperatures superconductors include successfully retaining a dissipation-free state while carrying large electrical currents. The controlled combination of two effective pinning centers (randomly distributed nanoparticles and self-assembled columnar defects) has been observed. By changing the temperature or growth rate during pulsed-laser deposition of barium zirconium oxide-(BaZrO3)-doped yttrium barium copper oxide (YBa2Cu3O7) films, the ratio of these self-assembled columnar defects is variable by tuning the field and angular critical-current (Ic) performance to maximize Ic. The self-assembled columnar defects' microstructure involves a mixture of splayed columnar defects and random nanoparticles. The very high Icarises from a complex vortex pinning landscape, wherein columnar defects provide large pinning energy, and wherein splay and nanoparticles inhibit flux creep. The related art has used the foregoing observations to produce thick films with higher Ic(H) and nearly isotropic angle dependence.

All related art high-Tcmaterials are type-II superconductors. As such, when these related art high-Tcmaterials are in the presence of a sufficiently high magnetic field, the magnetic field penetrates the material in physically distinct quantized topological structures known as magnetic-flux lines or vortices. The material within the vortex core is then forced into the normal state. The flow of an electrical super-current through the material exerts a force on the vortices, which, if free to move, will then dissipate energy resulting in the destruction of the dissipation-less conductive state. Some natural defects may occur within related art high-Tcmaterials, which serve as natural pinning sites for vortices, because of weakening or completely suppressing the superconducting state within the volume of these sites, however, the random nature of these natural defects provides only random pinning strength at these sites.

In the related art, reaching a high critical current density has been a major challenge and most of the focus has been on merely optimizing the geometry of the pinning landscape. Therefore, a need exists in the related art for the development of materials, devices, and methods for producing strong magnetic-flux pinning in superconducting materials using alternative techniques.

SUMMARY

The present disclosure involves superconducting materials. In accordance with an embodiment of the present disclosure, an enhanced superconducting material, having a magnetic-flux pinning by way of sites having high electronic effective mass m* and charge carrier density p, and methods of making the same are disclosed. The enhanced superconducting material is comprised of a superconducting host material and a dopant pinning material. The dopant pinning material being inert in relation to the superconducting host material wherein the value of the relationship between the square root of the electronic resistivity, ρ, and the effective mass, m* (√ρ/m*) is in a range less than that of the superconducting host material. The method of making such an enhanced superconducting material includes applying or doping the dopant pinning material doping on to the superconducting host material. By specifically configuring the dopant pinning material, the superconducting material of the present disclosure yields a uniform material configured to increase pinning strength for vortices by way of structuring the functionality and ordering pinning sites in a superconducting host material.

Corresponding reference numerals or characters indicate corresponding components throughout the several figures of the Drawing. Elements in the several figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be emphasized relative to other elements for facilitating understanding of the various presently disclosed embodiments. Also, common, but well-understood, elements that are useful or necessary in commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments of the present disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENT(S)

Referring toFIG. 1, this diagram illustrates, in a perspective view, a superconducting material100having magnetic-flux pinning by way of sites having high electronic effective mass m* and charge carrier density ρ, in accordance with an embodiment of the present disclosure. The superconducting material100comprises: a superconducting host material102and a dopant pinning material103being inert in relation to the superconducting host material102. Wherein the value of the relationship between the square root of the electronic resistivity, ρ, and the effective mass, m* (√ρ/m*) is in a range less than that of the superconducting host material102The dopant pinning material103is used for doping the superconducting host material102. The superconducting material100further comprises a substrate101, wherein the substrate101comprises at least one of: aluminum oxide (Al2O3), magnesium oxide (MgO), magnesium aluminate (MgAl2O4), zinc oxide (ZnO), strontium titanate (SrTiO3), lanthanum aluminate (LaAlO3), lithium niobate (LiNbO3), neodynium gallate (NdGaO3), strontium lanthanum aluminate (SrLaAlO3), strontium lanthanum gallate (SrLaGaO3), ytterbium aluminate (YtAlO3), yttria-(Y2O3)-stabilized zirconia (ZrO2) (YSZ), or any other suitable substrate material. A suitable substrate material comprises at least one characteristic of: a structurally matching lattice interface, a melting point in a range of at least approximately 800° C., a non-reactive chemical composition, or at least one insulating electrical property.

Still referring toFIG. 1A, the dopant pinning material103comprises an A-site ordered perovskite oxide, whereby the superconducting host material102is configurable to exhibit heavy fermion behavior at pinning sites therein. The A-site ordered perovskite oxide comprises a form of A copper rubidium oxide (ACu3Ru4O12), wherein A comprises at least one of an alkaline earth metal, a rare-earth metal, and at least one other element, such as an alkali metal, yttrium (Y), cadmium (Cd), scandium (Sc), and lanthanum (La), and wherein B comprises a transition metal. The superconducting host material102comprises a high-Tccompound, wherein the high-Tccompound comprises at least one of another form of yttrium barium copper oxide (YBa2Cu3O7-δ) and any material, such as a form of barium copper oxide having a compositional form of R1-yMyBa2Cu3-zTzOx, wherein 6≤x≤7, wherein 0≤y≤1, wherein 0≤z≤1, wherein R comprises at least one of a rare earth and calcium, wherein M comprises at least one of a rare earth distinct from that of R and calcium if absent from R, wherein T comprises at least one of cobalt (Co), iron (Fe), nickel (Ni), and zinc (Zn). The A-site ordered perovskite oxide comprises ACu3Ru4O12, wherein A comprises one of sodium (Na), calcium (Ca), and lanthanum (La). The high-Tccompound, comprising YBa2Cu3O7-δ, comprises YBa2Cu3O6.96.

Still referring toFIG. 1, the superconducting host material102comprises a plurality of superconducting material layers102a, each superconducting material layer102aof the plurality of superconducting material layers102acomprising a thickness in a range of approximately 5 lattice constants to approximately 20 lattice constants, in accordance with an embodiment of the present disclosure. The dopant pinning material103comprises a thin interlayer103adisposed between each superconducting material layer102aof the plurality of superconducting material layers102, the thin interlayer103aconfigurable as at least one of a top layer formed on each superconducting material layer102aand as separately formed interlayer, and the thin interlayer103acomprising a thickness in a range of approximately 1 lattice constant to approximately 10 lattice constants.

Still referring toFIG. 1, under the proper conditions, e.g., wherein the dopant pinning material103is chemically inert in relation to the superconducting host material102, and wherein the ratio of √{square root over (ρ)}/m* of the dopant pinning material103is less than that of the superconducting host material102, the materials, devices, and methods of the present disclosure are utilizable for increasing the current-carrying capacity, e.g., the critical current density, of any superconducting material of the present disclosure in at least one form, such as a bulk polycrystalline form, a single crystal form, and a thin film form, wherein m*=the electronic effective mass, and wherein ρ=charge carrier density (FIG. 2).

Still referring toFIG. 1, the superconducting materials of the present disclosure comprise properties, such as entering into an electronically ordered state, thereby supporting the transport of an electrical current without any dissipation of energy, e.g., the value of the electrical resistivity of the superconducting materials goes to zero when below a critical temperature Tc. The superconducting materials of the present disclosure have strong magnetic flux pinning and are utilizable in numerous technological applications, whereby such technological applications will benefit or become viable with a sufficient increase over existing values in the related art.

Referring toFIG. 2, this diagram illustrates, in a perspective view, a lattice structure103bof the dopant pinning material103, such as configured in the thin interlayer103a, in accordance with an embodiment of the present disclosure. The superconducting host materials102of the present disclosure have strong magnetic flux pinning may comprise type-II superconductors capable of transferring to a mixed state, e.g., a flux line lattice, in a sufficiently strong magnetic field. The critical current in this state is determined by the pinning force, e.g., by a flux line lattice interaction with non-homogeneities of the superconducting materials. Two types of pinning-force dependence on the magnetic field exist. For strong pinning, the pinning-force dependence has a smooth, wide maximum at fields in a range of approximately 0.3Hc2to approximately 0.5Hc2. For weak pinning, usually in a wide range of fields, the pinning force weakly depends on the magnetic field; and, only near Hc2, the pinning force has a narrow and very high maximum, e.g., a “peak effect” is utilized.

Referring toFIG. 3, this diagram illustrates, in a cross-sectional view, a superconducting material100having a strong magnetic-flux pinning by way of sites having high electronic effective mass m* and charge carrier density ρ, as shown inFIG. 1, in accordance with an embodiment of the present disclosure. In accordance with embodiments of the present disclosure, the materials, devices, and methods generally involve a distinct manner of controlling the quantum fluctuations of vortices in order to realize a significant increase in the current-carrying capacity of a superconducting material in the presence of a magnetic field. Such control is performed by directly increasing the effective quantum mechanical mass of pinned magnetic vortices200through the introduction of non-reactive materials as point, line, and volume imperfections, e.g., Q˜√{square root over (ρN)}/m*, wherein Q=the effective quantum mechanical mass, wherein ρN=charge carrier density within a vortex core V, and wherein m*=electronic effective mass within the vortex core V. In accordance with the present disclosure, the dopant pinning material103exhibit bulk properties of relatively low electronic resistivity, ρ, and a large electronic effective mass, m*. To achieve an enhancement in the effective pinning strength of the defect, e.g., at a pinned magnetic vortex200, the ratio of √{square root over (ρ)}/m*of the dopant pinning material103is less than that of the superconducting host material102in the normal state √{square root over (ρN)}/m* at magnetic fields and temperatures above approximately the upper critical field Hc2(T).

Still referring toFIG. 2, in accordance with embodiments of the present disclosure, the materials, devices, and methods generally involve minimizing vortex excitations that arise from quantum fluctuations. In a high-Tcsuperconductor, the strength of excitations from quantum fluctuations comprises comparable magnitude or even exceeds those of thermal fluctuations under certain circumstances. With the inclusion of a “dopant” material, such as the dopant pinning material103, as a source of defects whose electronic properties are such that quantum fluctuations can be heavily suppressed, the materials, devices, and methods provide an enhancement of the critical current density by an order of magnitude beyond what is provided by the geometric suppression of thermal fluctuations alone, e.g., an enhanced pining pinning of the vortex core V in the thin interlayer103a, the thin interlayer103acomprising a heavy fermion layer, wherein “heavy” related relates to the quantum mechanical mass.

Referring back toFIGS. 1, 2, and 3, in accordance with embodiments of the present disclosure, the materials, devices, and methods generally involve are useable for any combination of materials, wherein the dopant pinning material103comprises the following features: (1) inert in relation to the superconducting host material102, and (2) √{square root over (ρ)}/m* is less than that of the superconducting host material102. The use of the A-site ordered perovskite oxides of the form ACu3B4O12, wherein A comprises at least one of an alkaline earth metal, a rare-earth metal, and at least one other element, and wherein B comprises a transition metal, whereby superconducting host material102is configurable, by doping, by way of the dopant pinning material103, to exhibit heavy fermion behavior as pinning sites, such as pinned magnetic vortices200, therein, e.g., within a high-Tccompound, such as YBa2Cu3O7-δ, wherein δ is a number in a range of approximately 0 to approximately 1. The materials, devices, and methods involve using heavy fermion compounds ACu3Ru4O12, wherein A comprises one of sodium (Na), calcium (Ca), and lanthanum (La). For comparison, in YBa2Cu3O6.96, the quantity √{square root over (ρN)}/m* is approximately 1.8; and, in ACu3Ru4O12, wherein A comprises one of Na, Ca, La, the quantity √{square root over (ρ)}/m* is, respectively, approximately 0.11, approximately 0.22, and approximately 0.34.

Still referring back toFIGS. 1, 2 and 3, in an embodiment, a superconducting material100comprises a multilayer film, the multilayer film comprising a plurality of superconducting host material layers102a; and a thin interlayer103adisposed between each superconducting host material layer102aof the plurality of superconducting material host layers102a, wherein the thin interlayer103ais configurable as one of a top layer grown on each superconducting host material layer102aand as separately formed thin interlayer103a. A requirement for this approach is that the two materials, e.g., the dopant pining material103and the superconducting host material layer102a, are structurally compatible as in relation to the foregoing fermion compounds.

Still referring back toFIGS. 1, 2, and 3, in accordance with an embodiment of the present disclosure, a superconducting material100with a strong magnetic-flux pinning by way of sites, such as pinned magnetic vortices200, having high electronic effective mass m* and charge carrier density ρ, the superconducting material100comprises a superconducting host material102; and a dopant pinning material103being inert in relation to the superconducting host material102and having a √{square root over (ρ)}/m* in a range less than that of the superconducting host material102, the dopant pinning material103doping the superconducting host material102.

Still referring back toFIGS. 1, 2, and 3, in accordance with an embodiments of the present disclosure, the dopant pinning material comprises an A-site ordered perovskite oxide, whereby the superconducting host material is configurable to exhibit heavy fermion behavior as pinning sites therein, the A-site ordered perovskite oxide comprises a form of ACu3B4O12, A comprises at least one of an alkaline earth metal, a rare-earth metal, and at least one other element, B comprises a transition metal, the superconducting host material comprises a high-Tccompound, the high-Tccompound comprises YBa2Cu3O7-δ, the A-site ordered perovskite oxide comprises ACu3Ru4O12, A comprising one of Na, Ca, and La, and the high-Tccompound, comprising YBa2Cu3O7-δ, comprises YBa2Cu3O6.96. The high-Tccompound comprises at least one of YBa2Cu3O7-δand any material having a compositional form of R1-yMyBa2Cu3-zTzOx, wherein 6≤x≤7, wherein 0≤y≤1, wherein 0≤z≤1, wherein R comprises at least one of a rare earth and calcium, wherein M comprises at least one of a rare earth distinct from that of R and calcium if absent from R, and wherein T comprises at least one of cobalt, iron, nickel, and zinc.

Still referring back toFIGS. 1, 2, and 3, the present disclosure involves materials, devices, and methods for producing strong magnetic-flux pinning in superconducting materials, such as the superconducting material100, by including sites, such as pinned magnetic vortices200, having high electronic effective mass m* and charge carrier density ρ. An approach of the present disclosure comprises countering vortex excitations resulting from quantum fluctuations. The superconducting materials100(high-Tcmaterials) of the present disclosure have numerous potential applications for at least that the superconducting materials100achieve certain technological benchmarks, such as reaching a high critical current density, wherein the high critical current density is the maximum amount of electrical current that can be passed through a unit cross-sectional area of a superconducting material in a dissipation-less state.

Still referring back toFIGS. 1, 2, and 3, in accordance with an embodiment of the present disclosure, the superconducting material100with a strong magnetic-flux pinning by way of sites, such as pinned magnetic vortices200, having high electronic effective mass m* and charge carrier density ρ, comprises: a superconducting host material102and a dopant pinning material103being inert in relation to the superconducting host material102and has a √{square root over (ρ)}/m* in a range less than that of the superconducting host material102; and the dopant pinning material103doping the superconducting host material102, wherein the dopant pinning material103is specifically configured, e.g., synthesized, whereby the superconducting material100overcomes many of the challenges in the related art, e.g., in a uniform material configured to increase pinning strength for vortices, such as pinned magnetic vortices200, by way of structuring the functionality and ordering pinning sites in a superconducting host material102.

Referring toFIGS. 1, 2, 3 and 4, the present disclosure provides a method M1of synthesizing a superconducting material100with a strong magnetic-flux pinning by way of sites having high electronic effective mass and charge carrier density, in accordance with an embodiment of the present disclosure. The method M1comprises: providing a superconducting host material, as indicated by block401; providing a dopant pinning material that is inert in relation to the superconducting host material and having a √{square root over (ρ)}/m* in a range less than that of the superconducting host material, as indicated by block402; and doping the superconducting host material with the dopant pinning material, as indicated by block403.

Still referring toFIGS. 1, 2, 3 and 4, providing a dopant pinning material, as indicated by block402, comprises providing an A-site ordered perovskite oxide, whereby the superconducting host material is configurable to exhibit heavy fermion behavior as pinning sites therein. Furthermore, providing the A-site ordered perovskite oxide comprises providing a form of ACu3B4O12, providing a form of ACu3B4O12comprises providing A as at least one of an alkaline earth metal, a rare-earth metal, and at least one other element, providing a form of ACu3B4O12comprises providing B as a transition metal. Providing the superconducting host material comprises providing a high-Tccompound, providing the high-Tccompound comprises providing YBa2Cu3O7-δ, providing the A-site ordered perovskite oxide comprises providing ACu3Ru4O12, wherein A comprises one of Na, Ca, and La, and providing the high-Tccompound, comprising providing YBa2Cu3O7-δ, comprises providing YBa2Cu3O6.96. The high-Tccompound comprises at least one of YBa2Cu3O7-δand any material having a compositional form of R1-yMyBa2Cu3-zTzOx, wherein 6≤x≤7, wherein 0≤y≤1, wherein 0≤z≤1, wherein R comprises at least one of a rare earth and calcium, wherein M comprises at least one of a rare earth distinct from that of R and calcium if absent from R, and wherein T comprises at least one of cobalt, iron, nickel, and zinc.

FIG. 5, discloses a method M2of increasing a current-carrying capacity of a superconducting material by controlling the quantum fluctuations of vortices in the presence of a magnetic field, in accordance with an embodiment of the present disclosure. The method M2comprises: providing a superconducting material with a strong magnetic-flux pinning, as indicated by block500, which provides superconducting material that comprises: providing a superconducting host material as indicated by block501; providing a dopant pinning material that is inert in relation to the superconducting host material and having a √ρ/m* in a range less than that of the superconducting host material, as indicated by block502; and doping the superconducting host material with the dopant pinning material, as indicated by block503; and directly increasing the effective quantum mechanical mass of pinned magnetic vortices by introducing at least one non-reactive material as at least one of a point defect, a line defect, and a volume defect, as indicated by block504. The method M2further comprises exposing the superconducting material to a magnetic field and a temperature above approximately an upper critical field Hc2(T), as indicated by block505, whereby an effective pinning strength of a defect is enhanced, thereby increasing the current-carrying capacity of the superconducting material.