Enhanced flux pinning in (Bi,Pb)-2223/Ag tapes by slight Pr-doping

Pu, M.H.; Song, Wenhai; Zhao, Bing; Wu, Xingcai; Sun, Yan; Du, Junjie; Fang, Jingzhong

doi:10.1016/s0921-4534(01)00408-7

Cited by 24 publications

(12 citation statements)

References 15 publications

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“…(2) At very low values of voltage, the linear E-J behavior can be discussed according to the thermally assisted flux flow (TAFF) as the free vortices are created below T c as a result of a finite penetration depth [67]. ( [40] when they substituted Pr 3+ ions at Ca site with very small percentages in (Bi,Pb)-2223/Ag tapes. On the other hand, the formation of (Bi,Pb)-2212 increases with x > 0.025 and could be residual at the grain boundaries.…”

Section: Characterization and Investigationmentioning

confidence: 99%

Electrical and mechanical properties of (Bi,Pb)-2223 substituted by holmium

et al. 2016

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Abstract:The effect of the partial substitution of Ca 2+ by Ho 3+ ions on the electrical and mechanical properties of the superconducting phase (Bi,Pb)-2223 was studied. Superconducting samples of the type (Bi 1.8 Pb 0.4 )Sr 2 Ca 2.1−x Ho x Cu 3.1 O 10+δ were prepared by solid-state reaction technique under ambient pressure, and characterized by means of X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The superconducting transition temperature T c and pseudogap temperature T * were estimated from electrical resistivity measurements, while the critical current density J c was determined from I-V curves. The electrical resistivity data were discussed according to bipolaron model in the absence of thermally excited individual polarons. The sample with x = 0.025 showed the highest phase volume fraction, T c , and J c . Room temperature Vickers microhardness measurements were carried out at different applied loads (0.25-5 N) in order to investigate the performance of the mechanical properties of (Bi 1.8 Pb 0.4 )Sr 2 Ca 2.1−x Ho x Cu 3.1 O 10+δ phase. It was found that all the samples exhibit normal indentation size effect (ISE). The Vickers microhardness number H V increased as x increased from 0 to 0.025. The experimental results were discussed in view of Meyer's law, Hays-Kendall (HK) approach, elastic/plastic deformation (EPD) model, and proportional specimen resistance (PSR) model. The load independent (true) microhardness of (Bi 1.8 Pb 0.4 )Sr 2 Ca 2.1−x Ho x Cu 3.1 O 10+δ superconducting samples showed identical behavior to that of the PSR model.

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Section: Characterization and Investigationmentioning

confidence: 99%

Electrical and mechanical properties of (Bi,Pb)-2223 substituted by holmium

et al. 2016

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“…Based on the above results, we concluded that the improvement of J c behavior under magnetic field originates from the introduction of effective pinning centers due to Fe ions partial substitution of Cu ions. Similar to Pr-doping in Bi2223/Ag tapes [5], for Fe doped sample, the local superconductivity is lost in the vicinity of randomly distributed Fe-ions, the defect region in the vicinity of Fe-ion may play a role of a normal-like defect. When Fe-doping level is lower, the normal-like defects may separate to each other and work as point-like pinning centers under applied magnetic fields.…”

Section: Resultsmentioning

confidence: 93%

“…J c decreases drastically with the increase of magnetic fields as a result of the motion of the magnetic flux lines, which arises from the weak flux pinning of the Bi-system materials [2]. Introducing artificial defects as extra pinning centers by means of physical and chemical doping is an effective method to improve the flux pinning ability of this material [3][4][5]. In our previous work, Cr ions had been introduced into Bi2223/Ag tapes to substitute partially Cu ions.…”

Section: Introductionmentioning

confidence: 99%

The Impact of Fe Doping on Jc Behavior of Bi2223/Ag Tapes under Magnetic Field

Xiao

Song

et al. 2002

phys. stat. sol. (a)

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Bi1.8Pb0.4Sr2Ca2.2Cu3—xFexOy silver‐sheathed (Bi2223/Ag) tapes with different Fe‐doping amounts, x = 0.001, 0.002, 0.003, 0.004, were fabricated by powder‐in‐tube (PIT) technique. It is found that the magnetic field dependence of critical current density Jc(H) is improved for samples with Fe‐doping amounts of x = 0.001, 0.002, and 0.003 at high magnetic fields, while the Jc(H) behavior deteriorates with Fe‐doping level increasing further. X‐ray diffraction analyses manifest that a small amount of Fe‐doping has little effect on the phase composition of Bi2223/Ag tapes. Scanning electron microscopy (SEM) observations do not show an obvious difference between un‐doped and Fe‐doped samples. It is concluded that the enhanced flux pinning originates from the introduction of effective pinning centers due to Fe ions partial substitution for Cu ions.

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“…Additionally, the width of the superconducting transition depends strongly on the anisotropy associated with the magnetic field direction with regard to the Cu-O planes (the c-axis) in the structure [35][36][37][38][39]. Flux pinning ability can also be estimated from the flux pinning force density and activation energy values because, as well known, the activation energy (mentioned as the potential barrier height) is generally regarded as a measure of flux pinning strength of a superconductor material [40,41]. The activation energy is inferred from TAFF theory described with Arrhenius equation [ρ = ρ 0 exp(−U 0 /k B T )], which will be dealt with in detail in results and discussion part.…”

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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Enhanced flux pinning in (Bi,Pb)-2223/Ag tapes by slight Pr-doping

Cited by 24 publications

References 15 publications

Electrical and mechanical properties of (Bi,Pb)-2223 substituted by holmium

Electrical and mechanical properties of (Bi,Pb)-2223 substituted by holmium

The Impact of Fe Doping on Jc Behavior of Bi2223/Ag Tapes under Magnetic Field

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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