Superconducting materials with high critical current density (Jc) properties under magnetic field and low-cost processes are required for superconducting applications such as high field magnets. To improve in-field Jc, nanorods and nanoparticles of BaMO (M: Hf, Zr, etc.) and defects of ion irradiation have been introduced into REBa2Cu3Oy (RE = Rare Earth: REBCO) and iron-based superconductors thin films[1-3]. In addition, the introduction of flux pinning centers increases the irreversibility field (Hirr, practical critical fields for applications) and reduces the anisotropy of Hirr. (La2-xBax)CuO4(LBCO) material is an interesting superconducting material because it has a maximal critical temperature (Tc) up to 30 K near optimal doping and a different anisotropy than REBCO and iron pnictide superconductors. However, there are few reports of the in-field superconducting properties such as critical fields (Hc2), Hirr and Jc for LBCO thin films.
In this study, in order to study the in-field properties for LBCO materials, we fabricated LBCO films on the LAO substrate using by Trifluoroacetates Metal Organic Deposition (TFA-MOD) method. The electrical resistivity measurements were used by four probe method. The LBCO films had its superconducting transition temperature Tconset=30 K. In-field measurements were carried out by mainly using 20 T cryogen-free superconducting magnet in HFLSM (Tohoku university). Although the upper critical field (Hc2) at B||c significantly decreases with increases magnetic field, the Hc2 at B||ab does not decrease much. The mass anisotropy ratio is calculated using angular dependence of Hc2 [4], we obtained γH=6.8 for LBCO films which is slightly larger than that of REBCO(γH=5). Detailed superconducting properties (Hc2, Hirr and anisotropy) for LBCO films will be presented.
Acknowledgements:
This work was supported by JST-FOREST (Grant Number JPMJFR202G).
Reference:
[1] M. Miura et al., NPG Asia Materials 9 (2017) e447
[2] M. Miura et al., Nat. Commun. 4 (2013) 2499
[3] T. Ozaki et al., Nat. Commun. 7 (2016) 13036
[4] G. Blatter et al. Rev. Mod. Phys. 66 (1994) 1125.
Keywords: LBCO, anisotropy, irreversibility field, upper critical field