DocumentCode :
789735
Title :
Pulsed electrical breakdown from superconducting electrodes in vacuum diodes
Author :
Shkuratov, Sergei I.
Author_Institution :
Inst. of Electrophys., Acad. of Sci., Ekaterinburg, Russia
Volume :
2
Issue :
2
fYear :
1995
fDate :
4/1/1995 12:00:00 AM
Firstpage :
251
Lastpage :
262
Abstract :
Results are presented of investigations of the pulsed electric strength and threshold current densities of YBa2Cu3O7 and Nb cathodes at cryogenic temperatures. It has been shown that the cooling of a Nb cathode from 300 to 4.2 K leads to a 1.5 to 2.5× increase of pulsed electric strength and that the transition of the cathode from the normal to the superconducting state has no effect on either the breakdown delay time or the threshold current density of cathode micropoints. An analysis is made of the process of heating of cathode micropoints from cryogenic temperatures under the action of high-density field emission current. Experiments have shown that the atomic structure and electronic properties of Nb cathode micropoints and the dynamics of their heating are the same for Nb cathode tips having an atomically smooth and clean surface. We did not observe this effect for YBa2Cu3O7-x single crystal cathodes. That is why the prebreakdown phenomena in diodes with YBa2Cu 3O7-x electrodes are similar to those in diodes with metallic ones. Data are presented of the work function, limiting current densities, and tensile strength of YBa2Cu3O7-x single crystal cathode tips
Keywords :
barium compounds; cathodes; cryogenics; diodes; electric breakdown; electric strength; electron field emission; high-temperature superconductors; niobium; superconducting device testing; type II superconductors; vacuum tubes; work function; yttrium compounds; 300 to 4.2 K; Nb; YBa2Cu3O7; atomic structure; breakdown delay time; cathode micropoints; cooling; cryogenic temperatures; electronic properties; high-density field emission current; limiting current densities; prebreakdown phenomena; pulsed electric strength; pulsed electrical breakdown; superconducting electrodes; tensile strength; threshold current densities; threshold current density; vacuum diodes; work function; Cathodes; Cooling; Cryogenics; Diodes; Electric breakdown; Electrodes; Heating; Niobium; Temperature; Threshold current;
fLanguage :
English
Journal_Title :
Dielectrics and Electrical Insulation, IEEE Transactions on
Publisher :
ieee
ISSN :
1070-9878
Type :
jour
DOI :
10.1109/94.388248
Filename :
388248
Link To Document :
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