High-frequency absorption in melt-textured high- Tc YBaCuO superconductors

Abstract

The melt-textured YBa 2Cu 3O 7− x superconductors are studied using two techniques namely, microwave (MW) (41 GHz) grazing incidence reflectivity and radiofrequency (RF) (2.5 MHz) resonant absorptivity. The studies are carried out in temperature interval 77–300 K. The samples were prepared using commercial prereacted YBa 2Cu 3O 7− x powder. Seeding by SmBa 2Cu 3O x crystal produces a single domain material. The obtained results are considered in terms of the sample absorption property dependence on temperature and the plane (top, bottom and side). MW absorption depends on the sample plane and on position of studied part on the sample plane even at 300 K. Nonmonotony in temperature dependence of absorption is observed for some planes. On the other hand, the temperature dependence of RF absorption for all of the samples displays two-phase nature which manifests itself in the best way for bottom plane.