Presentation Information
[WBP1-23]Sr0.95La0.05TiO3 / Ni Conductive Buffer Layer for Ag-free REBCO Wires
*Tsubasa Uchida1, Koki Katayama1, Akiyoshi Matsumoto2, Takumi Ikenoue1, Toshiya Doi1 (1. Kyoto Univ. (Japan), 2. NIMS (Japan))
Keywords:
YBa2Cu3O7,Conductive Buffer Layer,La doped SrTiO3,Ag-free REBCO wire
[Purpose]
Toward the realization of Ag-free REBCO wire, we have been investigating a wire structure that does not require the deposition of Ag and Cu layers on top of the REBCO layer, using a {100}<001> textured Cu tape as the substrate and conductive materials as the buffer layer. We had fabricated the YBa2Cu3O7 (YBCO) wire using Ni and SrTi1-xNbxO3 (Nb-STO) as the conductive buffer layers (Nb-STO was deposited on the Ni layer). The Jc of the YBCO layer was 2.5 MA/cm2, and the resistivity of the Nb-STO in the thickness direction was 1 ~ 5 Ωcm[1]. We consider that the resistivity of the Nb-STO layer was not low enough to use Nb-STO as the conductive buffer layer of the REBCO wires. The resistivity of the Nb-STO layer increased since the oxygen diffused into the Nb-STO layer during the deposition of the YBCO layer. Thus, we apply Sr0.95La0.05TiO3 (La-STO) instead of Nb-STO as the conductive buffer material.
[Method]
Ni-electroplated Cu/SUS316L laminate tapes were used (Sumitomo Electric Industries, Ltd.) as the substrates. A SUS316L tape with a thickness of 100 μm was bonded to a 17 μm thick {100}<001> textured Cu tape. A 2 μm thick Ni layer was electro-deposited epitaxially on the surface of the Cu tape (Ni/Cu/SUS316L). We deposited the La-STO layer of 80 ~ 800 nm thick on the Ni/Su/SUS316L tape in a 97%Ar + 3%H2 atmosphere of 10-3 ~ 10-1 Pa by a pulsed laser deposition method (PLD method) at 650 ~ 900℃. Then we deposited the YBCO layer of 300 nm thick on the La-STO layer in an O2 atmosphere of 35 Pa by the PLD method at 760℃.
[Results]
We measured the X-ray (102)YBCO pole figure of the sample (see Figure 2 in the full-abstract). Four peaks at (α, β) = (55, 0), (55, 90), (55, 180), (55, 270) are observed in the X-ray (102)YBCO pole figure of the sample.
[Consideration]
The YBCO layer deposited on the La-STO layer on the Ni/Cu/SUS316L tape has a biaxial crystal alignment.
[Conclusion]
The biaxially aligned YBCO layer was obtained on the conductive La-STO buffered Ni / Cu / SUS316L tape.
References
1)T. Doi et al. Appl. Phys. Express. Vol 12, p023010, 2019.
Toward the realization of Ag-free REBCO wire, we have been investigating a wire structure that does not require the deposition of Ag and Cu layers on top of the REBCO layer, using a {100}<001> textured Cu tape as the substrate and conductive materials as the buffer layer. We had fabricated the YBa2Cu3O7 (YBCO) wire using Ni and SrTi1-xNbxO3 (Nb-STO) as the conductive buffer layers (Nb-STO was deposited on the Ni layer). The Jc of the YBCO layer was 2.5 MA/cm2, and the resistivity of the Nb-STO in the thickness direction was 1 ~ 5 Ωcm[1]. We consider that the resistivity of the Nb-STO layer was not low enough to use Nb-STO as the conductive buffer layer of the REBCO wires. The resistivity of the Nb-STO layer increased since the oxygen diffused into the Nb-STO layer during the deposition of the YBCO layer. Thus, we apply Sr0.95La0.05TiO3 (La-STO) instead of Nb-STO as the conductive buffer material.
[Method]
Ni-electroplated Cu/SUS316L laminate tapes were used (Sumitomo Electric Industries, Ltd.) as the substrates. A SUS316L tape with a thickness of 100 μm was bonded to a 17 μm thick {100}<001> textured Cu tape. A 2 μm thick Ni layer was electro-deposited epitaxially on the surface of the Cu tape (Ni/Cu/SUS316L). We deposited the La-STO layer of 80 ~ 800 nm thick on the Ni/Su/SUS316L tape in a 97%Ar + 3%H2 atmosphere of 10-3 ~ 10-1 Pa by a pulsed laser deposition method (PLD method) at 650 ~ 900℃. Then we deposited the YBCO layer of 300 nm thick on the La-STO layer in an O2 atmosphere of 35 Pa by the PLD method at 760℃.
[Results]
We measured the X-ray (102)YBCO pole figure of the sample (see Figure 2 in the full-abstract). Four peaks at (α, β) = (55, 0), (55, 90), (55, 180), (55, 270) are observed in the X-ray (102)YBCO pole figure of the sample.
[Consideration]
The YBCO layer deposited on the La-STO layer on the Ni/Cu/SUS316L tape has a biaxial crystal alignment.
[Conclusion]
The biaxially aligned YBCO layer was obtained on the conductive La-STO buffered Ni / Cu / SUS316L tape.
References
1)T. Doi et al. Appl. Phys. Express. Vol 12, p023010, 2019.