TY - JOUR
T1 - Engineering of pinning sites in melt-processed (Nd0.33Eu0.33Gd0.33)Ba2Cu3Oy superconductors
AU - Koblischka, Michael R.
AU - Muralidhar, Miryala
AU - Murakami, Masato
N1 - Funding Information:
We acknowledge valuable discussions with J.R. Clem, J.R. Thompson, M.W. McElfresh, T.H. Johansen, K. Fossheim, A. Erb, M. Däumling and Ø. Fischer. This work was partially supported by NEDO for the R&D of Indust. Sci. and Tech. Frontier program. MMD is thankful to the Iwate Techno Foundation, Iwate, Japan for providing the financial assistance, and MRK thanks the Japanese Science and Technology Agency (STA) for providing the fellowship.
PY - 1999/10/29
Y1 - 1999/10/29
N2 - Extremely fine normal-conducting particles could be uniformly dispersed in the superconductive matrix through a combination of Pt addition and a mixture of three different LRE (LRE: `light rare earths', i.e. Nd, Eu, Gd) elements in the LRE-Ba2Cu3Oy system. Although (Nd,Eu,Gd)2BaCuO5 powders about 3 μm in diameter were added to the precursor, we have found that Gd2BaCuO5 (Gd-211) inclusions about 0.1 μm in diameter were finely distributed in the (Nd,Eu,Gd)Ba2Cu3Oy matrix. The formation of such fine normal-conducting particles has not been achieved in any other bulk superconductors like YBa2Cu3O7 or NdBa2Cu3O7. The presence of small Gd-211 did not inhibit the function of flux pinning provided by composition fluctuations leading to a spatial scatter of the superconducting transition temperature, Tc, which is typically observed in LRE-Ba2Cu3Oy materials, which have a LRE1-xBa2-xCU3Oy-type solid solution. Therefore, two different pinning centers are simultaneously active in one sample, which is also confirmed by the pinning analysis based on the scaling formalism, and leading to a record high current density for bulk high temperature superconductors at 77 K.
AB - Extremely fine normal-conducting particles could be uniformly dispersed in the superconductive matrix through a combination of Pt addition and a mixture of three different LRE (LRE: `light rare earths', i.e. Nd, Eu, Gd) elements in the LRE-Ba2Cu3Oy system. Although (Nd,Eu,Gd)2BaCuO5 powders about 3 μm in diameter were added to the precursor, we have found that Gd2BaCuO5 (Gd-211) inclusions about 0.1 μm in diameter were finely distributed in the (Nd,Eu,Gd)Ba2Cu3Oy matrix. The formation of such fine normal-conducting particles has not been achieved in any other bulk superconductors like YBa2Cu3O7 or NdBa2Cu3O7. The presence of small Gd-211 did not inhibit the function of flux pinning provided by composition fluctuations leading to a spatial scatter of the superconducting transition temperature, Tc, which is typically observed in LRE-Ba2Cu3Oy materials, which have a LRE1-xBa2-xCU3Oy-type solid solution. Therefore, two different pinning centers are simultaneously active in one sample, which is also confirmed by the pinning analysis based on the scaling formalism, and leading to a record high current density for bulk high temperature superconductors at 77 K.
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U2 - 10.1016/S0921-5107(99)00198-1
DO - 10.1016/S0921-5107(99)00198-1
M3 - Article
AN - SCOPUS:0033204702
VL - 65
SP - 58
EP - 65
JO - Materials Science and Engineering B: Solid-State Materials for Advanced Technology
JF - Materials Science and Engineering B: Solid-State Materials for Advanced Technology
SN - 0921-5107
IS - 1
ER -