Absorption of microwave radiation field by HTSC ceramics: pressing effect

The paper studies the impact of cold pressing on SHF-properties of HTSC ceramics. SHF-properties improve in the low pressure region (up to 3 kbar): absorption minimum grows in the zero magnetic filed. In the region of of medium pressures (from 3 to 6 kbar), absorption maximum is rewided in the zero magnetic field instend of absorption minimum. The occurrence of such inversive signal is exploined by the formation of a surface layer whose superconducting properties differ from those of the internal region. In the high pressure region (6 and above 6 kbar), SHF-properties of the sample change significantly whish reflects a strong alternation of HTSC material structure under pressure