Important defeats on pinning of 2D pancake vortices in highly anisotropic Bi-2212 superconducting matrix with homovalent Bi/La substitution

Zalaoğlu, Y.; Büyükuslu, H.; Sarıtekin, N. K.; Varılcı, A.; Terzioğlu, C.; Görür, O.

doi:10.1016/j.jallcom.2015.01.095

Cited by 38 publications

(10 citation statements)

References 56 publications

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“…It is also known that Cu-O bond lengths in repeatedly stacked layers of Cu-O 2 layers regulate the size of the base plane. Moreover, Pb foreign substances increase the a-axis length as a result of an increase in Cu-O bond length and effective Cu valance [20][21][22][23][24][25][26]. XRD measurements also provide information on impurity phases.…”

Section: Xrd Measurement Evidencesmentioning

confidence: 99%

Improving Superconductivity, Microstructure, and Mechanical Properties by Substituting Different Ionic Pb Elements to Bi and Ca Elements in Bi-2223 Superconductors

Sarıtekin

Uzumcu

2022

J Supercond Nov Magn

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In this detailed study, the changes of microstructural, mechanical, and superconducting features of bulk Bi1.8Pb0.2Sr2.0Ca1.8Pb0.2Cu3Oy materials prepared at different milling time intervals (0.5 h ≤ x ≤ 8 h) were investigated in the most precise manner. The measurements of X-ray powder diffraction (XRD) and Vickers microhardness (Hv) were designed to scrutinize the bulk BSCCO samples. All the results of the measurements and calculations show that the characteristics responsible for the applications of the technology, industry, and engineering are significantly improved up to the 3 h milling time beyond that they tend to deteriorate. The enhancement of the characters is generally related to the transition from underdoped level of the (Bi, Pb)-2223 to the optimum level with the milling duration and this event approves that sufficient Pb nanoparticles penetrate the crystal structure. On the other hand, some of the reasons for the suppression in the superconducting properties are the presence of the porosity, disorder, defects, and the localization problem in the Cu-O2 consecutively stacked layers. In addition to those mentioned above, the other reasons are degradation in the crystallinity, reduction in the average crystallite size, and decrease in mobile hole concentration in the Cu-O2 layers. Similarly, the Pb inclusion rises the artificial random dislocations and grain boundary weak-links in the (Bi, Pb)-2223 superconducting system. Vickers microhardness measurements show that (Bi, Pb)-2223 bulk superconducting specimens exhibit typical indentation size behavior depending on the presence of both elastic and plastic deformations in the system. The results obtained from the hardness measurements have been analyzed by using Meyer law, PRS model, MPRS model, elastic–plastic deformation model, and Hays-Kendall approach. As a result, the Hays-Kendall approach was identified as the most successful model in describing the mechanical properties of the samples.

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Section: Xrd Measurement Evidencesmentioning

confidence: 99%

Improving Superconductivity, Microstructure, and Mechanical Properties by Substituting Different Ionic Pb Elements to Bi and Ca Elements in Bi-2223 Superconductors

Sarıtekin

Uzumcu

2022

J Supercond Nov Magn

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“…In other words, the magnitude of the room temperature resistivity changes by about a factor of 6 with the changes of the Nd inclusions in the HcN superconducting core. The main reason for the increase in the resistivity with the excessive Nd atoms is the decrease in mobile hole concentration (hole localization effect) of the Cu-sites in the Y-123 system, resulting in the phase transition from optimally doped to the underdoped position in the crystal array [36,37]. Furthermore, the thermodynamic fluctuations or the opening of spin-gap mechanism (considered as the small curvatures above the ( T c onset ) values) confirm the penetration of the magnetic impurities (Nd nanoparticles) into the superconducting system [38].…”

Section: Electrical Resistivity Measurementsmentioning

confidence: 99%

The Successful Incorporation of Nd Into Ba Site of Y0.9Ho0.1Ba2-yNdyCu3O7-δ Bulk Superconductors

Sarıtekin

Uzumcu

2022

J. Mod. Mech. Eng. Technol.

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This inclusive study reports the effect of the Nd atoms on the mechanical, microstructural, electrical and superconducting characteristics of Y0.9Ho0.1Ba2-yNdyCu3O7-δ superconductors with the aid of standard characterization methods, including X-ray diffraction, scanning electron microscopy, the bulk density, dc resistivity, and transport critical current density. The experimental results such as the degree of granularity, hole localization effect, room temperature resistivity, critical transition temperature, degree of the broadening, thermodynamic fluctuations, crystallinity, crystal plane alignments, crystal structure, grain size, phase purity and lattice parameters, the appearance of flux pinning centers, grain boundary weak-links, surface morphologies elemental compositions and distributions belonging to Y-site Ho and Ba-site Nd substituted Y-123 superconducting samples are discussed in detail for the first time. All the experimental findings show that the microstructural, electrical, mechanical and superconducting properties regularly improve with the increment in the HcN (Ho constant+Nd changeble) until a certain value of y=0.100, beyond which the characteristics tend to retrograde rapidly. This is attributed to the fact that excess penetration of the Nd damages the crucial properties given above.

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“…Interaction of pancake vortices with structural defects, created for instance by fast neutrons irradiation, considered in the present paper, plays essential function in the transport current flow process through HTc multilayered superconductors and is observed in critical current and current-voltage characteristics. Pancake vortices are most relevant in Bi-2212 superconductors [1][2][3][4][5], where anisotropy effects occur. In the paper it will be analyzed individual interaction of pancake type vortices appearing in the multilayered copper-oxide based HTc superconductors with nano-sized defects, created by fast neutrons irradiation, for geometry of the magnetic field perpendicular to the superconducting layers, through which current flows.…”

Section: Model Presentationmentioning

confidence: 99%

New model of the pinning potential barrier in layered HTc superconductors

Sosnowski

2016

Mod. Phys. Lett. B

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New model of the pinning potential barrier in multi-layered HTc superconductors has been presented, basing on geometrical approach to the capturing interaction of pancake type vortices with nano-scale defects. Using this model the transport current flow phenomena in these materials, especially current-voltage characteristics and critical current density, have been considered. Details of theoretical analysis are given, including derivation of basic mathematical equations describing the potential barrier in the function of transport current density and initial position of captured pancake vortex. Computer simulation has been performed then of influence of transport current amplitude on potential barrier height for various sizes of pinning centers and initial pancake vortex position as well as influence of fast neutrons irradiation on critical current of HTc layered superconductor. Model presentationHigh temperature oxide superconductors are very attractive materials from applied, technical point of view, especially promising in electrical engineering applications. Firstly it is expected and already realized applications of HTc materials in superconducting cryocables, fault current limiters and SMES-s (Superconducting Magnets Energy Storages) as well as superconducting motors more economic, of small dimensions and noiseless. For more efficient use of these unique materials in devices it is necessary however to be more familiar with especial electromagnetic properties of them, caused by multilayered structure leading to characteristic shape of magnetic vortices called now pancake type. Interaction of pancake vortices with structural defects, created for instance by fast neutrons irradiation, considered in the present paper, plays essential function in the transport current flow process through HTc multilayered superconductors and is observed in critical current and current-voltage characteristics. Pancake vortices are most relevant in Bi-2212 superconductors [1][2][3][4][5], where anisotropy effects occur. In the paper it will be analyzed individual interaction of pancake type vortices appearing in the multilayered copper-oxide based HTc superconductors with nano-sized defects, created by fast neutrons irradiation, for geometry of the magnetic field perpendicular to the superconducting layers, through which current flows. Then pancake vortices bring regular form of the short rigid cylinder, while anisotropy effects and Josephson's coupling in present, first approach are neglected. From the thin pancake structure of parallel vortices the flux cutting effects also do not appear, while multi-vortices interaction is in this model taken into account only through analysis of the change of elasticity energy of the vortex lattice during the capturing process. In the model is considered geometry of the ordered nano-defects, which form square lattice repeated in each superconducting layer. More advances geometries and physical cases will be considered in next papers, while present one

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Important defeats on pinning of 2D pancake vortices in highly anisotropic Bi-2212 superconducting matrix with homovalent Bi/La substitution

Cited by 38 publications

References 56 publications

Improving Superconductivity, Microstructure, and Mechanical Properties by Substituting Different Ionic Pb Elements to Bi and Ca Elements in Bi-2223 Superconductors

Improving Superconductivity, Microstructure, and Mechanical Properties by Substituting Different Ionic Pb Elements to Bi and Ca Elements in Bi-2223 Superconductors

The Successful Incorporation of Nd Into Ba Site of Y0.9Ho0.1Ba2-yNdyCu3O7-δ Bulk Superconductors

New model of the pinning potential barrier in layered HTc superconductors

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