Effect of Er-substitution on superconducting and metal-insulator transitions in 2212 bismuth cuprate

Sattar, Abdus; Srivastava, J.P.; Sharma, Sameer; Nath, T. K.

doi:10.1016/0921-4534(96)00360-7

Cited by 14 publications

(7 citation statements)

References 17 publications

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“…This lowers the carrier concentration in the samples and degrades the superconducting properties, as is also indicated by resistivity data. 3 The peak near 645 cm~1 is, generally, attributed to the stretching vibration of O(4) and O(5) in Bi layers. A g Most of the earlier workers5,9,10 observed this peak and assigned it similarly.…”

Section: Resultsmentioning

confidence: 98%

“…The wavenumber of this mode decreases suddenly above an Er concentration of x \ 0.45, the critical concentration at which the sample shows insulating properties. 3 We believe that this change is due to the excess of oxygen in the system on account of doping which ultimately changes the lattice parameters. In general, the decrease in wavenumber, *l8 /l8 , is larger than the increase in the lattice parameter, *b/b.…”

Section: Resultsmentioning

confidence: 99%

“…Our results of measurements of resistivity and XRD of the present system have been reported elsewhere. 3 We report here the results of micro-Raman scattering measurements on the above system and attempt to explain the observed vibrational features. This is the Ðrst microRaman measurement on this system and its results are correlated with our earlier measurements.…”

Section: Introductionmentioning

confidence: 96%

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Micro-Raman study of polycrystalline Bi2Sr2Ca1-xErxCu2O8+δ (0.0x1.0) composition

Sattar¹,

Srivastava²,

Sharma³

et al. 1997

J. Raman Spectrosc.

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Section: Resultsmentioning

confidence: 98%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 96%

See 1 more Smart Citation

Micro-Raman study of polycrystalline Bi2Sr2Ca1-xErxCu2O8+δ (0.0x1.0) composition

Sattar¹,

Srivastava²,

Sharma³

et al. 1997

J. Raman Spectrosc.

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“…Their undoped samples have shown a predominant single phase of "2223," whereas the contribution of the "2212" phase is observed in the samples with Er doping of x=0.005 to x=0.020 and the "2201" phase was observed in traces. Bi 2 Sr 2 Ca 1−x Er x Cu 2 O 8+δ (0.0≤ x ≤1.0) samples of A. Sattar et al [14] have shown an orthorhombic crystal structure with a space group of PMMM. By increasing the concentration (x) of "Er," the a-axis remained unchanged, the b-axis increased, whereas the c-axis decreased with increased Er doping.…”

Section: Introductionmentioning

confidence: 98%

Enhancement of Inter-plane Coupling and Superconductivity in Cu0.5Tl0.5Ba2(Ca3−yM y )Cu4O12−δ (M = 0, Pr, Y, Er, Gd; y = 0.02) Samples

Khan

Ashraf

Safeer

2016

J Supercond Nov Magn

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Cu 0.5 Tl 0.5 Ba 2 (Ca 3−y M y )Cu 4 O 12−δ (M=0, Pr, Y, Er, Gd; y=0.02) samples are synthesized at normal pressure to see the effect of M +3 elements doping in enhancing the inter-plane coupling of Cu 0.5 Tl 0.5 Ba 2 (Ca 3−y M y )Cu 4 O 12−δ superconductors. These samples have shown the tetragonal crystal structure in which the axis lengths increase with doping of rare-earth impurities. In the resistivity measurements, these samples have shown metallic variations of resistivity from room temperature down to the onset of superconductivity. The onset of superconductivity, the zero resistivity critical temperature, and the magnitude of diamagnetism are suppressed with the doping of rare-earth impurities at Ca sites. The excess conductivity analysis has shown suppression in the onset temperature of 3D and 2D Lawrence-Doniach (LD) conductivity regimes. The coherence length along the c-axis (ξ c(0) ), the inter-layer coupling (J ), and the Fermi velocity (V F ) of the carriers are suppressed with Y doping, whereas the values of these parameters increase with the doping of Er and Gd. However, the values of B c0 (T ), B c1 (T ), and J c (0) are suppressed with the doping of Y, Er, and Gd. Moreover, the values of magnetic field penetration depth (λ pd ) and the Ginzburg-Landau (GL) parameter κ increase with the doping of rare-earth elements. Since the λ pd is related inversely to the density of mobile carriers in the conducting CuO 2 planes, the increase in values of these parameters indicates that the density of mobile carriers is suppressed in the conducting planes with the doping of rare-earth elements. These studies stress the pivotal role of mobile charge carriers in the mechanism of high-T c superconductivity and have shown that M +3 rareearth elements develop some localization of the carriers in their neighborhood, thereby suppressing the values of essential superconductivity parameters.Keywords Cu 0.5 Tl 0.5 Ba 2 (Ca 3−y M y )Cu 4 O 12−δ (M = 0, Pr, Y, Er, Gd, y = 0.02) superconductors · Decoupling of CuO 2 planes · Enhanced flux pinning · Longer coherence length

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“…The suppression of superconductivity with rare earth substitution in the Bi-2212 system has engaged the attraction of many research groups who have studied the various physical properties of the system and tried to understand them [4,5]. In the Er doped system the suppression of superconductivity due to disorder was explained with the Ortuno-Pollak model [6]. Rare earth substitutions like Y increase the oxygen ratio in the Bi-O plane and also the modulation structure was reported by Kamba et al [7].…”

Section: Introductionmentioning

confidence: 99%

Texturing studies on bulk crystals

Prabhakaran

Subramanian

1998

Supercond. Sci. Technol.

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Textured crystals of have been grown by the platinum strip heater-floating zone technique. Texturing ratio and phase purity (Bi-2212) of the grown crystals were calculated from the x-ray diffraction data. Chemical compositions of the grown crystals were quantified from the inductively coupled plasma analysis. was found to be increased by 2 K for a lower level of substitution and a superconductor to semiconductor transition was observed for the higher order Y substitution. Oxygen stoichiometries of the Y substituted crystals were quantified from the iodometry titration method. Micro-twinning along the growth axis was revealed during etching studies for the cleaved crystals.

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Effect of Er-substitution on superconducting and metal-insulator transitions in 2212 bismuth cuprate

Cited by 14 publications

References 17 publications

Micro-Raman study of polycrystalline Bi2Sr2Ca1-xErxCu2O8+δ (0.0x1.0) composition

Micro-Raman study of polycrystalline Bi2Sr2Ca1-xErxCu2O8+δ (0.0x1.0) composition

Enhancement of Inter-plane Coupling and Superconductivity in Cu0.5Tl0.5Ba2(Ca3−yM y )Cu4O12−δ (M = 0, Pr, Y, Er, Gd; y = 0.02) Samples

Texturing studies on bulk crystals

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