In order to improve the flux pinning properties of GdBa2Cu3O7-δ(Gd123) superconductors, the introduction of BaMO3 (BMO, M=Hf, Zr, etc.) as artificial pinning centers (APCs) is widely known [1][2]. However, because of the large lattice misfit of BaMO3 with the base material and its tendency to coarsen the crystals, the c-axis of Gd123 is not oriented when more than 3 vol% of BaMO3 is introduced. In this study, we tried to introduce the superconductor Gd2CuO4(Gd214) (TC=18 K) as an APC, which has not been reported before. The reason for this is that Gd214 has a smaller lattice misfit with the base material, so more APCs can be expected to be introduced compared to the conventional BaMO3. As a result, we succeeded in introducing 6.23 vol% of Gd214 without any loss of crystallinity of the base material, and the maximum JC at 4.2 K was obtained in the film with 2.02 vol% of Gd214, with values of 8.13 MA/cm2 at 0.5 T and 3.05 MA/cm2 at 3 T. The values were 1.99 and 2.21 times higher than those of the non-doped film, respectively.
[1] T. Yoshihara et al., “BaMO3 (M = Zr, Hf) Doped REBCO Tapes Fabricated by Fluorine-Free MOD,” IEEE Trans. Appl. Supercond., vol. 33, no, 5, Aug. 2023, Art. no. 6600205.
[2] N. Kobayashi, O. Miura and, R. Kita, "Improvement of flux pinning properties for hafnium-doped Gd123 thin films fabricated by fluorine-free MOD method", IEEE Trans. Appl. Supercond., vol. 27, no. 4, Jun. 2017, Art. no. 8001104.
This work was supported by JSPS KAKENHI Grant Number JP 24KJ1858
Keywords: RE123, BMO, fluorine-free metal organic deposition, critical current density, high-JC superconductor.