Strong reduction of field-dependent microwave surface resistancein Y Ba 2 Cu 3 O 7 − δ with submicrometric Ba Zr O 3 inclusions

• Published in: Applied physics letters 2007-10, Vol.91 (18), p.182507-182507-3
• Main Authors: Pompeo, N., Rogai, R., Silva, E., Augieri, A., Galluzzi, V., Celentano, G.
• Format: Article
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.2803856

We observe a strong reduction of the field induced thin film surface resistance measured at high microwave frequency ( ν = 47.7 GHz ) in Y Ba 2 Cu 3 O 7 − δ thin films grown on Sr Ti O 3 substrates, as a consequence of the introduction of submicrometric Ba Zr O 3 particles. The field increase of the surface resistance is smaller by a factor of ∼ 3 in the film with Ba Zr O 3 inclusions, while the zero-field properties are not much affected. Combining surface resistance and surface reactance data, we conclude (a) that Ba Zr O 3 inclusions determine very deep and steep pinning wells and (b) that the pinning changes nature with respect to the pure film.