Field emission current from high-Tc ceramic cathodes

In this work the result of emission phenomena investigations are presented. Experiments were conducted for high-Tc superconducting ceramics YBaCuO and BiPbSrCaCuO. Fowler-Nordheim characteristics and the current-temperature dependencies were observed for superconducting and non-superconducting cathodes. It was noticed that the emission current value abruptly changed in the vicinity of the critical temperature. All measurements were done in a vacuum chamber at [10.sup.-6] Pa. X-ray diffraction analysis and scanning electron microscopy examination of the ceramic electrodes were performed also.