High critical current density and strong pinning efficiency for Fe-based superconductor, K-doped BaFe2As2, were achieved by naturally formed low-angle grain boundary networks. K-doped BaFe2As2 thin film is composed of columnar grains with widths of approximately 30–60 nm. The grains are rotated around the b- (or a-) axis by 1.5° and around the c-axis by −1°, resulting in the formation of low-angle grain boundary networks. The achieving superconducting properties are almost 10 times as high as the K-doped BaFe2As2 single crystal and comparable to ion-irradiated single crystal.
- Kazumasa Iida
- Dongyi Qin
- Akiyasu Yamamoto
