Detailed analysis on electrical conduction transition from 2D variable range hopping to phonon-assisted 3D VRH mechanism belonging to Bi-site La substituted Bi-2212 system

Zalaoğlu, Y.; Terzioğlu, C.; Görür, O.

doi:10.1016/j.jallcom.2014.10.150

Cited by 18 publications

(3 citation statements)

References 77 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Therefore, while the interlayer distances between the Cu-Ca-Cu and Ca-Sr sites in the layered structure increase, the interlayer spaces of the Sr-Bi, Bi-Bi, and Sr-Bi-Bi-Sr sites first expand and then contract automatically [17]. When the a/c ratio increases from 0.144 for Bi4 to 0.159 for Bi6, extra energy is naturally required for bond formation [18,19]. At the same time, the decrease in the c-parameter is related to the reduction in the hole concentration in CuO 2 planes.…”

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

View full text Add to dashboard Cite

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.

show abstract

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

View full text Add to dashboard Cite

show abstract

“…Hence, the interlayer distances between the Cu-Ca-Cu and Ca-Sr sites in the layered structure enlarge; however, the interlayer spaces of the Sr-Bi, Bi-Bi and Sr-Bi-Bi-Sr sites shorten automatically, so does c cell parameter [29]. Moreover, it is natural to confirm that the required extra energy for the bond formation gives rise to the contraction (from 37.02 to 30.72 Å ) of the c-axis length [30]. At the same time, as well known that the Cu-O bond length in the Cu-O 2 consecutively stacked layers arranges the size of the basal plane [31].…”

Section: Xrd Measurement Evidencesmentioning

confidence: 99%

Solubility limit of tetravalent Zr nanoparticles in Bi-2223 crystal lattice and evaluation of fundamental characteristic properties of new system

Sarıtekin

Terzioğlu

Pakdil

et al. 2015

J Mater Sci: Mater Electron

Self Cite

View full text Add to dashboard Cite

In this comprehensive work, we focus sensitively on the changes of microstructural, electrical, superconducting and mechanical properties belonging to the bulk Bi 1.7 Pb 0.4 Sr 2.0 Ca 2.0 Zr x Cu 3.1 O y materials with the different Zr nanoparticles (0 B x B 1.0) inserted in the superconducting matrix. The characterizations of the materials prepared are experimentally performed by bulk density, dc resistivity (q-T), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), electron dispersive X-ray (EDX) and Vickers microhardness (H v ) investigations. It is found that all the characteristics given above (especially superconducting properties) degrade considerably with the increment in the Zr addition level, and in fact they reach to the global minimum points in case of the maximum dopant level. The main reason of the rapid decrement in the electrical and superconducting properties stems from the presence of the localization problem in the Cu-O 2 consecutively stacked layers. Likewise, the Zr foreign addition increases the artificial random defects, dislocations and grain boundary weak-links in the superconducting system, even being favored by the SEM examinations. At the same time, the EDX surveys indicate that the Zr nanoparticles in the tetravalent state prefer to substitute for the divalent states of the Cu inclusions through the crystal structure as a result of their close ionic radius values (86 pm for Zr 4? ion and 87 pm for Cu 2? ion). Thus, the differentiation of the electronegativity reduces the mobile hole concentration in the Cu-O 2 slabs. Additionally, the XRD experimental findings show that there is a systematic decrement in the Bi-2223 (high) phase up to the Zr concentration level of x = 0.70 beyond which new characteristics peaks of ZrO 2 appear immediately. This is in relation to the fact that the solubility limit corresponding to the Zr foreign impurity in the Bi-2223 system is about x = 0.70. Similarly, the regular decrement in both the c-axis length and crystallite size with the dopant confirms the deterioration of the superconducting properties. Furthermore, the dramatic reduction of the H v values stems from the suppression of the crystallinity and connection quality in the intergrain coupling of the superconducting samples exhibiting typical Indentation Size Effect behavior due to the existence of both elastic and plastic deformations in the system.

show abstract

“…Additionally, researchers have concentrated their fundamental investigations related with the superconducting materials on high temperature superconductors (known as Type-II superconductor) [1]. Especially, within the Type-II superconductors, it is pointed out that studies are centered on the first type high temperature superconducting system without rare earth element, BSCCO [2][3][4][5][6][7][8]. This effective superconducting mechanism is composed of a generalized chemical formula Bi2Sr2Cay-1CuyOx where y value corresponds to 1, 2 and 3, respectively.…”

Section: Introductionmentioning

confidence: 99%

Determination of Solubility Characteristic of (Bi, Gd) Substitution in Bi-2223 Inorganic Materials

Zalaoğlu¹

2018

Sakarya University Journal of Science

View full text Add to dashboard Cite

In this study, it is examined the significant variations in the superconducting, electrical and structural belongings of Bi-site Gd nanoparticle substituted Bi-2223 crystal. The Bi2.0-xGdxSr2.0Ca2.1Cu3.2Oy (0≤x≤0.3) materials obtained with the standard solid state reaction technique are characterized by dc resistivity (ρ-T), X-ray diffraction (XRD) and transport critical current density (Jc) measurements. Moreover, all experimental findings as regards room temperature resistivity, residual resistivity, critical transition temperatures (𝑇 𝑐 𝑜𝑛𝑠𝑒𝑡 − 𝑇 𝑐 𝑜𝑓𝑓𝑠𝑒𝑡 ), crystallinity, lattice constant parameters, average crystallite size, phase fraction and strength quality of interaction between superconducting grains in the Bi-2223 ceramics declare that the structural, electrical and superconducting characteristics degrade systematically with the ascending of the Gd substitution level in the Bi-2223 samples. Furthermore, the major reason of the reduction trend observed especially in the electrical and superconducting features is in relation with the hole localization problem in the Cu-O2 layers. In this regard, grain boundary weak connections, dislocations and defects in the matrix considerably ascend with the enhancement of Gd nanoparticle substitution level.As seen from XRD measurements, it is clearly determined that there seems to be a decrement in the Bi-2223 phase with the enhancement of Gd inclusions up to the substitution amount of x=0.1. After this critical point, new characteristics peaks of Gd2O3 appear and measurement findings rapidly diminish to the minimum values. This substitution level emphasizes that the solubility limit of Gd is noted to be x=0.1 for Bi-2223. Likewise, the regular decrement observed c-axis length, critical current density and grain size favors the regular retrogression of the superconducting characteristics.

show abstract

Detailed analysis on electrical conduction transition from 2D variable range hopping to phonon-assisted 3D VRH mechanism belonging to Bi-site La substituted Bi-2212 system

Cited by 18 publications

References 77 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

Solubility limit of tetravalent Zr nanoparticles in Bi-2223 crystal lattice and evaluation of fundamental characteristic properties of new system

Determination of Solubility Characteristic of (Bi, Gd) Substitution in Bi-2223 Inorganic Materials

Contact Info

Product

Resources

About