Effects of cation substitution on flux pinning in Bi-2212 superconductors

Wakata, Mitsunobu; Takano, Shinjiro; Munakata, Fumio; Yamauchi, H.

doi:10.1016/0011-2275(92)90025-6

Cited by 26 publications

(11 citation statements)

References 9 publications

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“…The main advantages of Bi-based systems are their layered structure and hence texturing can be easily induced in it. 11,12 On the technological side the doping of Pb for Bi improve the superconducting properties of both bulks and tapes 13 and the doping of rare-earth ͑RE͒ ions in place of Ca/Sr stabilize the crystal structure of the system. These inherent properties lead to rapid flux creep that causes energy dissipation.…”

Section: Introductionmentioning

confidence: 99%

Enhancement of critical current density and flux pinning properties of Gd-doped (Bi, Pb)-2212 superconductor

Vinu

Sarun

Shabna

et al. 2008

Journal of Applied Physics

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The enhanced critical current density (JC) and flux pinning properties of Bi1.7Pb0.4Sr2-xGdxCa1.1Cu2.1O8+δ (where x=0.0, 0.1, 0.2, and 0.3) system prepared by solid-state synthesis in bulk polycrystalline form were studied. Phase analysis, microstructural investigation, and superconducting characterization were performed to evaluate the relative performance of the samples. The x-ray diffraction and energy dispersive spectroscopy analyses show that Gd atoms are successfully doped in place of Sr in the system. It is found that Gd in (Bi, Pb)-2212 enhances the critical temperature (TC), JC, and flux pinning strength of the system. The flux pinning force (FP) calculated from the field dependant JC values shows that the irreversibility line of the Gd-doped (Bi, Pb)-2212 shift toward higher fields to different extents depending on the value of x. The samples with x=0.2 show maximum FP of 645 kN m−3 and the peak position of FP shifts to higher fields (0.68 T) as against 26 kN m−3 and 0.12 T for the pure sample. Also, the values of self-field JC and pinning potential (U0) are maximum for this sample (x=0.2). The enhancements of TC, self-field JC, JC(B) characteristics, U0, and FP are explained on the basis of the hole optimization and formation of point defects due to the doping of Gd in (Bi, Pb)-2212 system.

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Section: Introductionmentioning

confidence: 99%

Enhancement of critical current density and flux pinning properties of Gd-doped (Bi, Pb)-2212 superconductor

Vinu

Sarun

Shabna

et al. 2008

Journal of Applied Physics

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“…Also the Pb-substituted Bi-2212 [(Bi, Pb)-2212] has shown enhanced J C s in applied fields, compared to the Pb-free Bi-2212 [7]. Again a few studies reported that the flux pinning strength of (Bi, Pb)-2212 increases by rare-earth (RE) doping [8][9][10] and the flux pinning ability is usually determined from the values of flux pinning force density and activation energy [8,11,12]. Because the activation energy is the potential barrier height, it is the measure of flux pinning strength of the superconductor.…”

Section: Introductionmentioning

confidence: 99%

Analysis of thermo-magnetic fluctuations in Bi1.6Pb0.5Sr2−xLuxCa1.1Cu2.1O8+δ (0.000≤x≤0.125) superconductor

Vinu

Sarun

Shabna

et al. 2009

Journal of Alloys and Compounds

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“…In order to overcome these problems appeared, the flux pinning mechanism in the film should be investigated in detail. In the recent works [12][13][14][15][16][17][18][19][20][21][22][23][24], the researchers have extensively analyzed the flux pinning mechanism in the superconducting state to introduce the effective pinning centers such as planar defects, stacking faults, and microdefects, resulting in thermally activated jumps; or hopping of flux lines; or flux bundles over an energy barrier [25,26]. Over the pinning energy barrier of a structure, the flux line might be thermally activated although the Lorentz force exerted on the flux bundle by the current is smaller than the pinning force [27][28][29][30].…”

Section: Introductionmentioning

confidence: 99%

Effect of Magnetic Field Direction on Magnetoresistivity, Activation Energy, Irreversibility and Upper Critical Field of Bi-2212 Thin Film Fabricated by DC Sputtering Method

Bal

Varılcı

2012

J Supercond Nov Magn

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This study aims to investigate the effect of magnetic field direction on superconducting properties of Bi-2212 thin film fabricated on MgO (100) substrate using the direct current (DC) magnetron reactive sputtering technique at 100 watt with the aid of magnetoresistivity measurements. The zero resistivity transition temperatures (T c ), irreversibility fields (μ 0 H irr ) and upper critical fields (μ 0 H c2 ) are deduced from the magnetoresistivity versus temperature curves under DC magnetic fields (parallel and perpendicular to c-axis) up to 5 T. Moreover, thermally activated flux flow (TAFF) model is studied for activation energy (U 0 ) values of the sample. It is found that the T c value decreases from 76.4 K to 39.1 K for the applied magnetic field perpendicular to c-axis (μ 0 H ⊥c-axis); likewise, the T c reduces towards 28.8 K with the increase in the applied field parallel to c-axis (μ 0 H c-axis). Furthermore, the U 0 values are found to decrease considerably with increasing applied magnetic field. In fact, the U 0 of 134.5 K is obtained to be smallest at 5 T field parallel to the c-axis. Additionally, both the μ 0 H irr and μ 0 H c2 values determined are also observed to reduce with the increase of the applied magnetic field. At absolute zero temperature (T = 0 K), the extrapolation of the μ 0 H irr (T ) and μ 0 H c2 (T ) curves is used to obtain the μ 0 H irr (0) and μ 0 H c2 (0) values of the film, respectively. The inner is found to be about 22.216 T (19.046 T) for the applied field perpendicular (parallel) to c-axis whereas the latter is determined to be about 54.095 T (126.522 T) for the applied field parallel (perpendicular) to c-axis, respectively, as a result of anisotropic behavior of the film prepared. On the other hand, penetration depths (λ) and coherence lengths (ξ ) inferred from μ 0 H irr (0) and μ 0 H c2 (0) values are obtained to be about 38.519 Å (41.601 Å) and 16.147 Å (24.685 Å) in the case of applied field perpendicular (parallel) to c-axis, respectively. Based on all the results, the change of the superconducting properties as a function of the magnetic field direction presents the anisotropy of the sample produced. X-ray diffraction (XRD) and scanning electron microscopy (SEM) examinations are also conducted for microstructural and phase analyses of the film.

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Effects of cation substitution on flux pinning in Bi-2212 superconductors

Cited by 26 publications

References 9 publications

Enhancement of critical current density and flux pinning properties of Gd-doped (Bi, Pb)-2212 superconductor

Enhancement of critical current density and flux pinning properties of Gd-doped (Bi, Pb)-2212 superconductor

Analysis of thermo-magnetic fluctuations in Bi1.6Pb0.5Sr2−xLuxCa1.1Cu2.1O8+δ (0.000≤x≤0.125) superconductor

Effect of Magnetic Field Direction on Magnetoresistivity, Activation Energy, Irreversibility and Upper Critical Field of Bi-2212 Thin Film Fabricated by DC Sputtering Method

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