Charge carrier localization and metal to insulator transition in cerium substituted (Bi,Pb)-2212 superconductor

Shabna, R.; Sarun, P.M.; Vinu, S.; Syamaprasad, U.

doi:10.1016/j.jallcom.2009.12.047

Cited by 48 publications

(14 citation statements)

References 21 publications

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“…The variation of lattice parameters a and c with Cr content in Bi 1.6 Pb 0.5 Sr 2 Pr x Ca 1.1 Cu 2.1 O y is depicted in Table 1. As seen from the table, the lattice constant, a, increases [29][30][31][32] while the lattice constant, c, decreases with the increase [27,[33][34][35] in the Cr addition. According to these results, the Bi-2212 phase decreases while the Bi-2201 phase starts to increase with the increase of the Cr addition; nevertheless, Fig.…”

Section: Xrd Analysesmentioning

confidence: 84%

Investigation of Structural and Superconducting Properties of Cr Added Bi-2212 Superconducting Ceramics

Yıldırım

Yücel

Bal

et al. 2011

J Supercond Nov Magn

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This study reports the effect of Cr addition on the structural and superconducting properties of Bi 1.8 Sr 2.0 Crx Ca 1.1 Cu 2.1 O y superconductor with x = 0, 0.1, 0.3, 0.5 0.7, and 1 by means of X-ray analysis (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and resistivity measurements. The samples studied in this work were prepared using the standard solid-state reaction method. Zero resistivity transition temperatures (T c ) are qualitatively estimated from the dc resistivity measurements. The zero resistivity transition temperatures are obtained to decrease from 81 K to 53 K with the increase in Cr addition. Moreover, the phase and lattice parameters were determined from XRD measurements. Based on the refinement of cell parameters done by considering the structural modulation, the Cr addition was confirmed by an increase of the lattice parameter a and decrease of the cell parameter a of the samples in comparison with that of the undoped sample (Cr0). As for the microstructure and element composition analyses on the surface of the samples produced, SEM and EDS measurements were investigated. According to the measurements, not only were the grain sizes of the samples noted to decrease, but also the surface morphology and grain connectivity were obtained to degrade with increase in the

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Section: Xrd Analysesmentioning

confidence: 84%

Investigation of Structural and Superconducting Properties of Cr Added Bi-2212 Superconducting Ceramics

Yıldırım

Yücel

Bal

et al. 2011

J Supercond Nov Magn

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“…One can see from the table, the percentage of (Bi, Pb)-2223 phase decreases and that of (Bi, Pb)-2212 phase increases with the Mn addition. Additionally, a systematic expansion in the a-axis length is observed [38][39][40][41] while a regular contraction in the c-axis length is obtained with the increase [42][43][44][45] in the Mn addition. It is well known that the lattice parameter a is controlled by the length of in-plane Cu-O bond [46].…”

Section: Xrd Analysesmentioning

confidence: 81%

Effect of Mn Addition on Structural and Superconducting Properties of (Bi, Pb)-2223 Superconducting Ceramics

Yıldırım

Bal

Yücel

et al. 2011

J Supercond Nov Magn

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This study deals with the effect of Mn addition on the structural and superconducting properties of Bi 1.8 Pb 0.4 Sr 2 Mn x Ca 2.2 Cu 3.0 O y ceramics with x = 0, 0.03, 0.06, 0.15, 0.3 and 0.6 by means of X-ray analysis (XRD), scanning electron microscopy (SEM), electron dispersive X-ray (EDX), resistivity, and transport critical current density (J c ) measurements. Zero-resistivity transition temperatures (T c ) of the samples produced via the standard solidstate reaction method are estimated from the dc resistivity measurements. Moreover, the phase fraction and lattice parameters are determined from XRD measurements while the microstructure, surface morphology and element composition analyses of the samples are investigated by SEM and EDX measurements, respectively. It is found that T c values are obtained to decrease from 109 K to 85 K; likewise, J c values are observed to reduce from 3200 A/cm 2 to 125 A/cm 2 with increasing Mn addition. According to the refinement of cell parameters done by considering the structural modulation, the Mn addition is confirmed by both an increase of the lattice parameter a and a decrease of the cell parameter c of the samples in comparison with that of the pure sample (Mn0). SEM measurements show that not only the surface morphology and grain connectivity are seen to degrade but the grain sizes of the samples are found to decrease with the increase of the Mn addition as well. The EDX results reveal that the elements used for the prepara-

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“…It is apparent from the table that the enhancement in the Zr addition level leads to expand the a-axis length values but contract in the c cell parameter as a result of the partial replacement of tetravalent Zr inclusions for the divalent Cu nanoparticles in the Bi-2223 system. Namely, the presence of the different aliovalent substitutions through the Bi-2223 crystal structure results in the positive charge in the oxygen deficient Bi-O double layers, and so the positive charge appeared needs to be balanced by the valency/oxygen for the charge neutrality [24][25][26][27][28]. 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].…”

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

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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.

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Charge carrier localization and metal to insulator transition in cerium substituted (Bi,Pb)-2212 superconductor

Cited by 48 publications

References 21 publications

Investigation of Structural and Superconducting Properties of Cr Added Bi-2212 Superconducting Ceramics

Investigation of Structural and Superconducting Properties of Cr Added Bi-2212 Superconducting Ceramics

Effect of Mn Addition on Structural and Superconducting Properties of (Bi, Pb)-2223 Superconducting Ceramics

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

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