We probe the short-range pinning properties with the application of microwave currents at very high driving frequencies (47.7 GHz) on YBa2Cu3O7-δfilms with and without sub-micrometer BaZrO3inclusions. We explore the temperature and field ranges 60 K < T < Tcand 0 <μ0H < 0.8 T, with the field applied along the c-axis. The magnetic field induces a much smaller increase of the microwave resistivity, Δρ1(H)+iΔρ2(H), in YBa2Cu3O7-δ/BaZrO3with respect to pure YBa2Cu3O7-δ. Δρ1(H) is slightly superlinear in pure YBa2Cu3O7-δ(suggesting a possible contribution of thermal activation), but linear or sublinear in YBa2Cu3O7-δ/BaZrO3(suggesting a possible suppression of thermal activation as a consequence of BaZrO3inclusions). These features persist up to close to Tc. We discuss our data in terms of the ratio r = Δ ρ2(H) / Δ ρ1(H) in the framework of the models for the microwave surface impedance in the mixed state. Large r are found in YBa2Cu3O7-δ/BaZrO3, with little field dependence. By contrast, smaller values and stronger field dependences are found in pure YBa2Cu3O7-δ. We discuss the different field dependence of the pinning constant. © 2008 Elsevier B.V. All rights reserved.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Energy Engineering and Power Technology
- Electrical and Electronic Engineering
Pompeo, N., Galluzzi, V., Rogai, R., Celentano, G., & Silva, E. (2008). Change of strength of vortex pinning in YBCO due to BaZrO. Physica C: Superconductivity and its Applications, 468(7-10), 745 - 748. https://doi.org/10.1016/j.physc.2007.11.040