Different regions of fluctuation conductivity in Sn-doped Cu0.5Tl0.5Ba2Ca2Cu3−ySnyO10−δ superconductors

Khan, Nawazish A.; Hassan, Najmul; Irfan, M.; Firdous, Tayyaba

doi:10.1016/j.physb.2009.12.036

Cited by 24 publications

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“…Analysis of the excess conductivity such as using the AL and LD models can give important parameters such as coherence length along c-axis, ξ c (0) [25][26][27], transition temperature, T 2D-3D [27][28][29], and interplanar coupling constant, J [30][31][32]. In (Cu,Tl)-based superconductors, i.e., (Cu,Tl)-1223 [33][34][35], (Cu,Tl)-1212 [36], and (Cu,Tl)-1245 [37] excess conductivity analysis revealed crossover from 2D to 3D transition behavior as temperature was lowered. Y123 [38,39] system have also shown 2D to 3D fluctuation behavior.…”

Section: Introductionmentioning

confidence: 99%

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Influence of Ce Substitution at Sr-Site on Superconducting Fluctuation Behavior and Infrared Absorption of Tl0.9Bi0.1Sr2−x Ce x Ca0.9Y0.1Cu1.99Fe0.01O7−δ (x=0–0.20) Ceramics

Ismail

Yahya

Khan

2012

J Supercond Nov Magn

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Ce substituted Tl 0.9 Bi 0.1 Sr 2−x Ce x Ca 0.9 Y 0.1 Cu 1.99 Fe 0.01 O 7−δ (x = 0-0.20) samples were synthesized to determine the effects of the higher valence ion substitution on superconductivity and structure of the Fe-doped Tl1212 derivatives. The normal state behavior for x = 0 showed semiconductor-like behavior which gradually turned to metallic behavior with increasing Ce at x = 0.05-0.15. However, further substitution of Ce for x > 0.15 turned the normal state to insulating behavior. The zero critical temperature, T c zero increased from 65.4 K (x = 0.05) to 71.0 K (x = 0.10), but slightly decreased for x > 0.10 indicating the optimum value of average copper valence was achieved at x = 0.10. Excess conductivity analysis using the Aslamazov Larkin, AL and Lawrence-Doniach, LD models revealed two-dimensional, 2D to three-dimensional, 3D transition of superconducting fluctuation behavior, SFB with the highest transition temperature, T 2D-3D at x = 0.10. FTIR analysis in conjunction with XRD results showed softening of FeO 2 /CuO 2 planar oxygen mode from 610.5 cm −1 (x = 0) to 605 cm −1 (x = 0.20) which is suggested to be related to possible increase of inter plane coupling, J and this is supported by computed results based on the LD model. The enhanced J increases superconducting coherence length along c-axis, ξ c (0), and hence lowers anisotropy, γ resulting in enhanced superconducting properties.

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Section: Introductionmentioning

confidence: 99%

“…The analysis of excess conductivity was carried out by using the AL and LD models as a framework to determine the effect of Ce on dimensionality of SFB [59], ξ c (0) [25][26][27], γ [33], and J [30][31][32]. FTIR absorption spectra were analyzed to investigate the changes in phonon modes as a result of the substitution.…”

Section: Introductionmentioning

confidence: 99%