Abstract
Nanoscale c-axis-aligned one dimensional artificial pinning centers (1D-APC) in superconducting YBa2Cu3O7-x (YBCO) films have been shown to provide strong correlated pining to magnetic vortices at magnetic field H//c-axis. A question arises on how the pinning effectiveness is sustained as the H-orientation (θ) deviates from the c-axis and how such an angular range is correlated to the pinning efficiency of an individual 1D-APC. To shed lights on this question, this work investigates the angular range of pinning effectiveness of the BaZrO3 (BZO) 1D-APCs in BZO/YBa2Cu3O7-x nanocomposites as the strain field overlap is systematically varied by increasing the BZO doping level in the range of 2-6 vol.% and by the introduction of the secondary Y2O3 nanoparticles (3D APCs). By evaluating the maximum pinning force density (Fp, max), its location Hmax, and the α values of the nanocomposites normalized to that of the reference YBa2Cu3O7-x film as functions of θ at temperatures of 65–77 K, a quantitative correlation between the pinning efficiency of the BZO 1D-APCs and their effective angular range was obtained. In most samples, the 1D-APCs can provide enhanced Hmax in the range of θ ∼0°-60°. However, the Fp, max values only in nanocomposites with high pinning efficiency 1D-APCs exceed that of the YBa2Cu3O7-x over a smaller range up to θ ∼ 37°. Finally, the introduction of 3D APCs results in reduction of the α values over nearly the entire angular range. This study reveals the importance in improving individual 1D-APC’s pinning efficiency and hence extending its angular range of effective pinning.
Highlights
Over the last decade or so, nanoscale artificial pinning centers (APCs) of a variety of morphologies have been reported in superconducting YBa2Cu3O7-x (YBCO) films on dielectric or metal substrates for enhancement of magnetic vortex pinning and critical current density Jc in applied magnetic fields (H)
To shed lights on this question, this work investigates the angular range of pinning effectiveness of the BaZrO3 (BZO) 1D-APCs in BZO/YBa2Cu3O7-x nanocomposites as the strain field overlap is systematically varied by increasing the BZO doping level in the range of 2-6 vol.% and by the introduction of the secondary Y2O3 nanoparticles (3D APCs)
This study reveals the importance in improving individual 1D-APC’s pinning efficiency and extending its angular range of effective pinning
Summary
Over the last decade or so, nanoscale artificial pinning centers (APCs) of a variety of morphologies have been reported in superconducting YBa2Cu3O7-x (YBCO) films on dielectric or metal substrates for enhancement of magnetic vortex pinning and critical current density Jc in applied magnetic fields (H). The first reported APC study on BaZrO3 (BZO) doped YBCO films was conducted by MacManus-Driscoll et al BZO doped YBCO films, which demonstrated a 5-fold improvement of Jc at 75.5 K and 7 T indicating enhanced pinning by the BZO APCs.. The first reported APC study on BaZrO3 (BZO) doped YBCO films was conducted by MacManus-Driscoll et al BZO doped YBCO films, which demonstrated a 5-fold improvement of Jc at 75.5 K and 7 T indicating enhanced pinning by the BZO APCs.3 This initiated many interesting works on generation of APCs and characterization of the pinning enhancement. Several insulator dopants are demonstrated to form 1D-APCs in YBCO through strain-mediated selfassembly during growth including BaZrO3 (BZO), BaSnO3(BSO), BaHfO3 (BHO) and Ba2Y(Nb/Ta)O6.15–17 Considering the 1DAPCs are effective only within a certain angular range around H//caxis, doping of APCs of mixed morphologies has been explored scitation.org/journal/adv recently for strong, as well as isotropic pinning at all orientations of the magnetic field, to meet the specifications of applications in high-field magnets, motors, generators, transformers, etc. For example, the secondary dopant, Y2O3, typically forms 3D APCs and can be combined with the primary BZO (BHO or BSO) 1D- APCs to form 1D+3D APC/YBCO nanocomposite films to reduce the H-orientation dependence of Jc.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
