Influence of ternary additions and precipitation on the critical current density and other superconducting properties in Nb-65 wt. %Ti

Panek, Marek; Pattanayak, D.; Meier‐Hirmer, R.; Küpfer, H.

doi:10.1063/1.331976

Cited by 16 publications

(11 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Cold drawing in NbTi wires creates dislocations. Panek et al [19] and Matsushita and Kupfer [20] demonstrated that dislocations form high-field pinning centers.…”

Section: Physical Properties and Pinning Centers In Nbti Wiresmentioning

confidence: 99%

“…Livingston [2] indicates that there are different types of pinning centers volume, surface, and point centers (e.g., precipitates and voids close to the coherence length). These pinning centers are most effective for increasing critical current density in low and medium magnetic fields [18][19][20]. In addition, Gajda et al [21] showed that these pinning centers in MgB 2 increase the critical current density (J c ) above 30 K, whereas pinning centers created by dislocations (line pinning centers) [2], substitution of C for B (lattice substitution pinning centers) [22], and precipitates inside the grain (inside grains pinning centers) [23] very effectively increase the J c in high magnetic fields [18].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Analysis Method of High-Field Pinning Centers in NbTi Wires and MgB2 Wires

Gajda

2018

J Low Temp Phys

View full text Add to dashboard Cite

The main purpose of this article is to show an easier and more accurate method for analyzing high-field pinning centers. Previous methods did not allow for precise analysis and research on high-field pinning centers, they studied only the dominant pinning mechanism, and they required a maximum of pinning force (F pmax) to analyze pinning centers. The main advantage of this method can be used in samples without the maximum pinning force required by other methods to analyze the pinning mechanism. In addition, this method allows us to observe even small changes in the density of individual pinning centers. This method is based on analysis of critical current density values in different ranges of reduced magnetic field. The method of analysis of highfield pinning centers allows primarily to develop methods and directions for creation of high-field pinning centers. The surface pinning centers are strong pinning centers in low magnetic fields and very weak pinning centers in middle and high magnetic fields. Additionally, the analysis of pinning centers shows that dislocations, strains, substitutions in the crystal lattice, and precipitation inside the grains create strong pinning centers in high magnetic fields and very weak pinning centers in low and middle magnetic fields. Research indicates that strains, substitutions in the crystal lattice, and precipitates inside grains form pinning centers that operate in the high magnetic field range.

show abstract

“…Cold drawing in NbTi wires creates dislocations. Panek et al [19] and Matsushita and Kupfer [20] demonstrated that dislocations form high-field pinning centers.…”

Section: Physical Properties and Pinning Centers In Nbti Wiresmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Analysis Method of High-Field Pinning Centers in NbTi Wires and MgB2 Wires

Gajda

2018

J Low Temp Phys

View full text Add to dashboard Cite

show abstract

“…The results presented in articles [8][9][10][11] suggest that high annealing pressure can improve the microstructure of MgB 2 material, reduce its void size, improve connections between the grains, allow smaller grains to be obtained and introduce strain-dislocations. In papers [12,13], the authors suggest that the dislocations create a line pinning center, which increases J c in high magnetic fields. The author in [14] suggests that the point pinning center can create not only intergranular precipitation but also voids similar in size to the coherence length; both are effective in pinning flux.…”

Section: Introductionmentioning

confidence: 99%

The influence of HIP on the homogeneity, J_c, B_irr, T_c and F_p in MgB₂ wires

Gajda¹,

Morawski

Zaleski

et al. 2014

Supercond. Sci. Technol.

View full text Add to dashboard Cite

Unreacted MgB2 wires were made at Hyper Tech Research, USA by a continuous tube forming and filling method using mixtures of Mg and B with and without SiC powder additions. All of the wires underwent hot isostatic pressure (HIP) treatment at the Institute of High Pressure. The first part of the wire was annealed at a pressure of 1 GPa, and the second part was annealed at 0.1 MPa. In this work, we show the influence of high pressure on critical current density (Jc), pinning force (Fp), critical temperature (Tc), irreversible magnetic fields (Birr) and the Fp scaling and microstructure of MgB2 wires. The results obtained indicate that after annealing at high pressure, the MgB2 wires show increases of Jc and Fp in high magnetic fields (8 T–12 T); in SiC doped MgB2 wires, Fpmax shifts to higher magnetic fields. We also compared the Jc of the doped and undoped MgB2 wires (without HIP and with HIP). The scanning electron microscope (SEM) results show that HIP increases the density of MgB2 material and improves its uniformity.

show abstract

“…Identifying pinning centers and pinning mechanisms is of major importance for achieving higher critical currents in superconducting wires. In the early 1980s several flux line pinning (FLP) studies were made on the Nb-Ti system, considering the pinning produced by grain boundaries and small precipitates [1,2]. At that time, the defect microstructure of the optimized Nb-Ti conventional wires was often thought of as too complex for basic FLP studies.…”

Section: Introductionmentioning

confidence: 99%

Composition gradient as a source of pinning in Nb–Ti and NbTa–Ti superconductors

Bormio-Nunes

Sandim

Ghivelder

2007

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

Superconducting Nb-Ti and NbTa-Ti wires produced by solid-state diffusion were studied, correlating microstructural and transport properties. The most interesting result is that the diffusion layer sharp composition variation is an important source of pinning in these materials. Within this scenario, we suggest that the source of pinning centers in conventional NbTi wires should be reexamined, since the α-Ti precipitation creates a Nb gradient composition around it. We propose that in conventional superconducting wires there are actually two kinds of strong pinning centers. One is the well-known α-Ti normal interface and the new one now identified is the composition gradient around α-Ti precipitates.

show abstract

Influence of ternary additions and precipitation on the critical current density and other superconducting properties in Nb-65 wt. %Ti

Cited by 16 publications

References 22 publications

Analysis Method of High-Field Pinning Centers in NbTi Wires and MgB2 Wires

Analysis Method of High-Field Pinning Centers in NbTi Wires and MgB2 Wires

The influence of HIP on the homogeneity, J_c, B_irr, T_c and F_p in MgB₂ wires

Composition gradient as a source of pinning in Nb–Ti and NbTa–Ti superconductors

Contact Info

Product

Resources

About

Influence of ternary additions and precipitation on the critical current density and other superconducting properties in Nb-65 wt. %Ti

Cited by 16 publications

References 22 publications

Analysis Method of High-Field Pinning Centers in NbTi Wires and MgB2 Wires

Analysis Method of High-Field Pinning Centers in NbTi Wires and MgB2 Wires

The influence of HIP on the homogeneity, Jc, Birr, Tc and Fp in MgB2 wires

Composition gradient as a source of pinning in Nb–Ti and NbTa–Ti superconductors

Contact Info

Product

Resources

About

The influence of HIP on the homogeneity, J_c, B_irr, T_c and F_p in MgB₂ wires