Anisotropic magnetization and weak links in melt textured YBa2Cu3O7

Gomis, V.; Catalán, I.; Pérez, F.; Martı́nez, B.; Fontcuberta, J.; Fuertes, Amparo; Obradors, X.

doi:10.1016/0011-2275(93)90074-x

Cited by 4 publications

(2 citation statements)

References 22 publications

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“…The identification of this intermediate field region as a small-bundle regime has also been carried out by Civale et al in 123 single crystals [140]. This temperature-field region of the phase diagram corresponds to that where fishtail anomalies are usually detected in 123 materials [141]. Our work suggests that these anomalies originate in the small-bundle regime when the effects of interface pinning are moderate in melttextured 123 materials or null (single crystals) [104].…”

Section: Phase Diagramsupporting

confidence: 81%

Tailoring of microstructure and critical currents in directionally solidified

Sandiumenge

Martı́nez

Obradors

1997

Supercond. Sci. Technol.

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Directionally solidified composites display a complex microstructure with several defects coexisting in the matrix and hence the identification of the flux-pinning mechanisms requires a detailed analysis of the critical currents. In this work we review the formation mechanism of twins, stacking faults, microcracks, subgrain boundaries and dislocations in connection with the refining strategies of (211 phase) inclusions and modifications of the microstructure generated through prolonged oxygen annealings and high-temperature plastic deformation of the ceramic. The influence of these defects and post-processing treatments on the critical currents is then analysed focusing on their relative importance as flux-pinning centres at different temperatures and magnetic fields up to 20 T. A complete magnetic phase diagram is finally proposed as a basis for a systematic classification of the observed irreversible superconducting behaviour in single-grain melt-textured composites.

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Section: Phase Diagramsupporting

confidence: 81%

Tailoring of microstructure and critical currents in directionally solidified

Sandiumenge

Martı́nez

Obradors

1997

Supercond. Sci. Technol.

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“…16 This temperature range corresponds actually to that where usually fishtail anomalies are detected in YBa 2 Cu 3 O 7 . 53 Our work suggests that these anomalies originate in the small bundle regime when the effects of interface pinning is moderate or null as in single crystals. 52 The single vortex pinning regime observed in region I does not exist in single crystals because the thermal activation makes ineffective the weak pinning centers but when the cooperative effects of the flux-line lattice increase at high fields J c might be enhanced thus leading to fishtail anomalies.…”

Section: Discussionmentioning

confidence: 68%

Critical currents and pinning mechanisms in directionally solidifiedYBa2Cu3
Martı́nez
¹
,
Obradors
²
,
Gou
³

et al. 1996
Phys. Rev. B
130
3
44
1
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The superconducting properties of directionally solidified YBa 2 Cu 3 O 7 -Y 2 BaCuO 5 composites, with critical currents above 10 5 A/cm 2 at 77 K and zero magnetic field, are reported in a wide variety of samples having very different contents of Y 2 BaCuO 5 ͑211 phase͒ precipitates with different particle size and magnetic fields up to 22 T. The field, temperature, and composition dependence of the critical currents allow us to identify interfacial pinning by 211 precipitates as a very effective pinning mechanism. Nevertheless, single vortex interfacial pinning has a dominant role only in a narrow region below about 1 T and temperatures 40 KрTр80 K. In this region the system shows a behavior very akin to that observed in ion irradiated single crystals and described as correlated disorder. On lowering the temperature the thermal wandering of the vortex from secondary weak pinning centers decreases leading to a new single vortex pinning regime extending up to very high magnetic fields where a mixture of strong and weak pinning centers are active. On the other hand, increasing the magnetic field, the characteristic footprints of the small bundle and large bundle regimes are identified at intermediate temperatures. The former is found below the H-T line given by the maximum of the macroscopic pinning force while the latter is observed above this line up to the irreversibility line. Finally, collecting all these results together a magnetic phase diagram of the mixed state of the YBa 2 Cu 3 O 7 -Y 2 BaCuO 5 textured composites is proposed.

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AC susceptibility study of YBCO sintered samples near the transition temperature

Polichetti

Pace

Testa

et al. 1996

Solid State Communications

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Anisotropic magnetization and weak links in melt textured YBa2Cu3O7

Cited by 4 publications

References 22 publications

Tailoring of microstructure and critical currents in directionally solidified

Tailoring of microstructure and critical currents in directionally solidified

Critical currents and pinning mechanisms in directionally solidifiedYBa2Cu3
Martı́nez
¹
,
Obradors
²
,
Gou
³

et al. 1996
Phys. Rev. B
130
3
44
1
View full text Add to dashboard Cite

AC susceptibility study of YBCO sintered samples near the transition temperature

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Anisotropic magnetization and weak links in melt textured YBa2Cu3O7

Cited by 4 publications

References 22 publications

Tailoring of microstructure and critical currents in directionally solidified

Tailoring of microstructure and critical currents in directionally solidified

Critical currents and pinning mechanisms in directionally solidifiedYBa2Cu3Martı́nez1, Obradors2, Gou3 et al. 1996Phys. Rev. B1303441View full textAdd to dashboardCite

AC susceptibility study of YBCO sintered samples near the transition temperature

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About

Critical currents and pinning mechanisms in directionally solidifiedYBa2Cu3
Martı́nez
¹
,
Obradors
²
,
Gou
³

et al. 1996
Phys. Rev. B
130
3
44
1
View full text Add to dashboard Cite