TY - JOUR
T1 - Geometry dependence of intergranular currents in sintered YBa2Cu3O7-δ
AU - Schuster, Th
AU - Koblischka, M. R.
AU - Kuhn, H.
AU - Ludescher, B.
AU - Kronmüller, H.
N1 - Funding Information:
We acknowledgvea luabled iscussionws ith U. Ess-manna nd V. SkumryevT. he authorsw ish to thank R. Henesf or the samplep reparationa ndP. Keppler for the gold coatingsT. his work is financiallys up- portedb y theB undesministeriufmti Forschungu nd Technologie( Project 13N 57005).T his is gratefully acknowledged.
PY - 1992/11/15
Y1 - 1992/11/15
N2 - Using standard four-point terminal measurements, the intergranular critical current densities jJc(T, B) of sintered YBa2Cu3O7-δ samples are determined. The dependence of the critical current density on the sample geometry (height h and width b of parallel- epiped samples) is measured systematically for various temperatures (5K ≤ T ≤ 91 K) and low applied external magnetic fields (0 mT ≤ μ0Hext ≤ 10 mT). It is shown that the intergranular critical current density increases on reducing the sample height or width, if no external magnetic field is applied to the sample. The results are discussed using a model assuming the currents flowing in a surface layer of the sample. A reduction of the height or width of the sample changes the circumferences and not the current itself, thus implying an enhancement of the critical current density, jJc(T, B). It is found that the increase of jJc(T, B) on reducing the sample dimensions is limited by the Josephson penetration depth, λJ(T). This penetration depth, λJ(T), turns out to be a very important parameter to reach high intergranular critical current densities in sintered high-Tc superconductors.
AB - Using standard four-point terminal measurements, the intergranular critical current densities jJc(T, B) of sintered YBa2Cu3O7-δ samples are determined. The dependence of the critical current density on the sample geometry (height h and width b of parallel- epiped samples) is measured systematically for various temperatures (5K ≤ T ≤ 91 K) and low applied external magnetic fields (0 mT ≤ μ0Hext ≤ 10 mT). It is shown that the intergranular critical current density increases on reducing the sample height or width, if no external magnetic field is applied to the sample. The results are discussed using a model assuming the currents flowing in a surface layer of the sample. A reduction of the height or width of the sample changes the circumferences and not the current itself, thus implying an enhancement of the critical current density, jJc(T, B). It is found that the increase of jJc(T, B) on reducing the sample dimensions is limited by the Josephson penetration depth, λJ(T). This penetration depth, λJ(T), turns out to be a very important parameter to reach high intergranular critical current densities in sintered high-Tc superconductors.
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U2 - 10.1016/0921-4534(92)90167-B
DO - 10.1016/0921-4534(92)90167-B
M3 - Article
AN - SCOPUS:0026947573
VL - 202
SP - 249
EP - 255
JO - Physica C: Superconductivity and its Applications
JF - Physica C: Superconductivity and its Applications
SN - 0921-4534
IS - 3-4
ER -