Superconducting fluctuation and infrared absorption of Cd-substituted Tl0.9Bi0.1Sr1.8Yb0.2Ca1−xCdxCu1.99Fe0.01O7−δ ceramics

Ismail, Saidatul Akmar; Yahya, A. K.; Khan, Nawazish A.

doi:10.1016/j.ceramint.2012.10.073

Cited by 13 publications

(8 citation statements)

References 10 publications

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“…Moreover, Re substitution caused changes in T 2D−3D ; the highest transition was observed at x = 0.15 [26]. Excess conductivity analyses of ( [16] showed that Cd substitution influenced T 2D−3D , ξ c (0), and J . Interestingly, changes in ξ c (0) due to elemental substitution were also previously reported for other Tl-1212 compounds [20,21], Tl 0.5 Pb 0.5 Sr 2−x Yb x CaCu 2 O 7−δ [25] and Tl 1−x Cu x Sr 1.2 Yb 0.8 CaCu 2 O 7−δ [28].…”

Section: Resultsmentioning

confidence: 92%

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Superconducting Fluctuations and Excess Conductivity Analysis of Te-Substituted TlSr2(Ca1−x Te x )Cu2O7−δ

Al-Sharabi

Abd‐Shukor

2015

J Supercond Nov Magn

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Samples with nominal starting compositions TlSr 2 (Ca 1−x Te x )Cu 2 O 7−δ (x = 0.05-0.30) were prepared by the solid-state reaction method and studied by powder X-ray diffraction and electrical resistance measurements. The purpose of this work was to determine the valence state of Te in the TlSr 2 CaCu 2 O 7−δ (Tl-1212) phase. It is also to determine the dimension of fluctuation-induced conductivity λ, and the superconducting fluctuations and excess conductivity using the Aslamazov-Larkin (AL) theory. The Lawrence-Donaich (LD) theory was used to calculate the coherence length ξ c (0), interlayer coupling J , and anisotropy γ = (ξ ab (0)/ξ c (0)). X-ray powder diffraction patterns indicated that the samples were dominantly Tl-1212 phase. Temperature-dependent resistance measurements showed metallic normal-state behavior for all samples. The onset transition temperature, T c onset , was between 32 K (x = 0.05) and 61 K (x = 0.25). The valence of Te in Tl-1212 is suggested to be Te 6+ from the analysis of the highest T c in the x = 0.25 sample. Excess conductivity analyses showed that Te substitution induced 2D-to-3D conductivity transition with the highest transition temperature, T 2D−3D observed for x = 0.25. The calculations based on Lawrence-Doniach model showed the shortest coherence length, ξ c (0), and highest anisotropy (γ = 10.24) for the x = 0.25 sample.

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Section: Resultsmentioning

confidence: 92%

“…The linear resistivity versus temperature curve bends down above T c due to the enhanced conductivity, which is attributed to superconducting fluctuations [16]. Fluctuation-induced conductivity of superconductors has been analyzed to study the mechanism for enhancing T c and the optimization of charge carriers in the CuO 2 planes.…”

Section: Introductionmentioning

confidence: 99%

Superconducting Fluctuations and Excess Conductivity Analysis of Te-Substituted TlSr2(Ca1−x Te x )Cu2O7−δ

Al-Sharabi

Abd‐Shukor

2015

J Supercond Nov Magn

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“…For the series, FTIR absorption spectrum showed softening of apical oxygen mode with increasing substitution which in conjunction with the decrease in c-lattice parameter observed by XRD measurements indicate increase in distance between Tl-O and CuO 2 planes pointing to a decrease in separation between CuO 2 planes [24]. The decrease was suggested to cause increase in Fermi wave vector, k F and coherence length, ξ c (0).…”

Section: Introductionmentioning

confidence: 86%

“…The solid-state reaction technique has been used to prepare the polycrystalline Tl1212 samples with the nominal starting compositions Tl 0.9 Bi 0.1 Sr 1.8 Yb 0.2 Ca 1 À x Cd x Cu 1.99 Fe 0.01 O 7 À δ (x ¼0, 0.1, 0.2, 0.3 and 0.4) [24]. The samples were prepared by two steps.…”

Section: Methodsmentioning

confidence: 99%

“…On the other hand, quite recently, infrared absorption studies on Fe-doped TlSr1212 with composition Tl 0.9 Bi 0.1 Sr 1.8 Yb 0.2 Ca 1 À x Cd x Cu 1.99 Fe 0.01 O 7 À δ (x ¼0-0.4) revealed interesting features including optimization of superconducting properties with substitution of Cd 2 þ ion [24]. For the series, FTIR absorption spectrum showed softening of apical oxygen mode with increasing substitution which in conjunction with the decrease in c-lattice parameter observed by XRD measurements indicate increase in distance between Tl-O and CuO 2 planes pointing to a decrease in separation between CuO 2 planes [24].…”

Section: Introductionmentioning

confidence: 98%

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