In-field Performance Comparison and Vortex Pinning Analysis in Depth of Pristine and BaHfO3-Doped Y0.5Gd0.5Ba2Cu3O7-δ Films in Different Temperature Regions

• Published in: Journal of superconductivity and novel magnetism Vol. 35; no. 12; pp. 3505 - 3520
• Main Authors: Ye, Jiachao, Mou, Shaojing, Zhu, Rongji, Liu, Linfei, Li, Yijie
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.12.2022
• Subjects: Characterization and Evaluation of Materials; Condensed Matter Physics; Magnetic Materials; Magnetism; Original Paper; Physics; Physics and Astronomy; Strongly Correlated Systems; Superconductivity; Artificial pinning center; Cu; Y; Pinning contribution; Gd; BaHfO; Vortex pinning; Ba; O
• ISSN: 1557-1939; 1557-1947
• DOI: 10.1007/s10948-022-06427-x

Pristine Y 0.5 Gd 0.5 Ba 2 Cu 3 O 7- δ films and Y 0.5 Gd 0.5 Ba 2 Cu 3 O 7- δ films with additional 1 mol% and 3 mol% BaHfO 3 secondary phases were fabricated on a CeO 2 layer, and the microstructure and superconducting properties in the liquid helium, hydrogen, and nitrogen temperature regions were compared. BaHfO 3 dopants exist in the form of nanorods and cause lengthening of the Y 0.5 Gd 0.5 Ba 2 Cu 3 O 7- δ c -axis lattice and degradation of the texture due to the strain field, which, in turn, reduces the critical temperature and self-field critical current density. The field and temperature dependences of the transport characteristics were investigated in an applied magnetic field normal to the film by up to 9 T. The fitting on the normalized pinning force density shows effective modulation in the flux creep by doping BaHfO 3 over a wide temperature range, which is more significant with increasing doping concentrations. The analysis of the pinning contribution weight confirmed enhancement of the strong pinning by the BaHfO 3 nanorods over the entire temperature range, which further explained the weakened attenuation of the current transport capacity in the BaHfO 3 -doped films with an increasing field. The angular dependence measurement at 77.3 K showed that the BaHfO 3 nanorods along the c -axis effectively consolidated the pinning ability approaching the main growth orientation, which leads to improved in-field J c anisotropy.