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

Microwave bulk properties of melt-textured high-TCYBa2Cu3O7 superconductors

“…Since in this case a central part of the sample surface has been measured, the increase in absorption is conditioned by the properties of the SmBa 2 Cu 3 O X seeding crystal deposited in the central part of the surface of the top plane (figure 1(b)). The increase of absorption in the centre of the top plane was also shown in [2] at room temperature (in normal state).…”

“…One of the three samples (PT22) investigated in [2], with dimensions 21 × 21 mm h −1 × 15. 5 Y123 material, was chosen for the present study.…”

“…In order to remove the damaged surface layer, the sample was polished after cutting. The measurements were carried out at T = 77 K (the integral levitation force and field mapping measurements), in the temperature range T = 77-130 K (the microwave absorption measurements using the grazing incidence reflectivity technique [2][3][4] at frequency f = 41 GHz) and at 300 K (the SWR measurements using the same technique). The dimensions of the sample testing area, determined by dimensions of the inclined open ended waveguide window, is short-circuited by the sample surface, are 15 × 5.2 mm 2 (figure 1(a)), therefore the results are averaged over this area.…”

“…Recently [2], we have reported on the results of the measurements of microwave (MW) absorption on the top, bottom and sides of bulk melt-textured YBa 2 Cu 3 O 7−δ at T = 77 and 300 K. Based on these results, we have arrived at the conclusion on correlation of the measurement results in the superconducting (S) and normal (N) states. The grazing incidence microwave reflectivity technique has been used for the above mentioned measurements [3,4] (the microwave waveguide section is shown in figure 1(a)).…”