The critical current performance of REBa2Cu3Oy-coated conductors must be isotropically improved for use in high-field coil-based applications operated at low temperatures less than 50 K. The high and isotropic critical current densities (Jc) with respect to the directions of the magnetic field under these operating conditions were achieved by a 3.8 vol.% BaHfO3 (BHO)-doped SmBa2Cu3Oy (SmBCO) film on a metallic substrate deposited with low-temperature growth (L-BHO film). In particular, the L-BHO film attained a high flux pinning force density over 1.5 TN/m3 at a temperature of 4.2 K. From the anisotropic scaling approach based on the effective mass model, a high density of random pinning centers in the L-BHO film plays an important role in achieving the high Jc performance at 4.2 K. In order to reveal the reason why the L-BHO film includes high density of random pinning centers, we compared the flux pinning properties and the dominant flux pinning centers between the L-BHO film and the other two samples: A 3.8 vol.% BHO-doped SmBCO film fabricated with relatively high-temperature growth, and a nondoped SmBCO film fabricated with low-temperature growth. From the comparison, it is revealed that the random pinning centers are induced by BHO nanorods.
- coated conductor
- flux pinning
- random pinning center
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering