Directional Vortex Pinning at Microwave Frequency in YBa2Cu3O7−x Thin Films with BaZrO3 Nanorods

• Published in: Journal of superconductivity and novel magnetism Vol. 26; no. 5; pp. 2093 - 2097
• Main Authors: Pompeo, N., Torokhtii, K., Augieri, A., Celentano, G., Galluzzi, V., Silva, E.
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01-05-2013; Springer
• Subjects: Anisotropy; Barium zirconates; Characterization and Evaluation of Materials; Condensed Matter Physics; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Cuprates superconductors (high tc and insulating parent compounds); Exact sciences and technology; Fluid flow; Laser deposition; Magnetic Materials; Magnetism; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Microwaves; Nanorods; Nanostructure; Original Paper; Physics; Physics and Astronomy; Pinning; Properties of type I and type II superconductors; Strongly Correlated Systems; Superconductivity; Thin films; Vortex lattices ,flux pinning, flux creep; Vortices; Anisotropy; Vortex pinning; Nanorods; BaZrO; Barium Zirconates; Microwave radiation; Nanocolumn; Pulsed laser deposition; Inclusions; Preferred orientation; Thin films; Flux pinning; Vortices; Scaling laws; High-Tc superconductors; High frequency; Nanorod; Barium Copper Yttrium Oxides Mixed
• ISSN: 1557-1939; 1557-1947
• DOI: 10.1007/s10948-012-2060-9

We investigate the effect of the anisotropy and of the directional pinning in YBa
2
Cu
3
O
7−
x
films grown by pulsed laser ablation from targets containing BaZrO
3
at 5 mol%. BaZrO
3
inclusions self-assemble to give nanorods oriented along the
c
-axis, thus giving a preferential direction for vortex pinning. The directionality of vortex response is studied at high ac frequency with the complex microwave response at 48 GHz, as a function of the applied field and of the angle
θ
between the field and the
c
-axis. The complex microwave response does not exhibit any angular scaling, suggesting that the structural anisotropy of YBa
2
Cu
3
O
7−
x
is supplemented by at least another preferred orientation. The pinning parameter
r
shows evidence of directional pinning, effective in a wide range of angles around the
c
-axis (thus ascribed to BZO nanocolumns).