Relation of critical current irreversibility to trapped flux and microstructure in polycrystalline YBa2Cu3O7

✍ Scribed by J.E. Evetts; B.A. Glowacki

• Publisher: Elsevier Science
• Year: 1988
• Tongue: English
• Weight: 905 KB
• Volume: 28
• Category: Article
• ISSN: 0011-2275
• DOI: 10.1016/0011-2275(88)90147-6

✦ Synopsis

A study has been made of the cnt=cal current m silver clad YBa2Cu307 wires Detailed res=stwe trans,tlons, m zero magnetic field and w=th a magnet=c field apphed, indicate that below 10-3V m-1 these mater=als d~splay clear power law behawour of the form E=kl n w=th n values up to about 16 Th=s character=st~c =s s~m=lar to that seen m convent=onal superconducting compos=te w=res and has been related to the spatial distribution of mhomogenelty For higher electnc fields, E, there is a dewatlon from simple power law behawour as current is progresswely transferred to the sdver cladding It ~s shown that the vanat=on of voltage w=th magnet=c field at constant current can be related d=rectly to/c(B), the vanat=on of cr=t~cal current w=th apphed field The dependence of/c(B) on the smtermg conditions and amount of S=O2 =mpur=ty add~t=on =s presented and =t =s shown that / c versus B can be related to the Fraunhofer diffract=on structure for a d=stnbut~on of Josephson junct=ons =n an apphed field It =s further observed that Ic(B) for all samples shows a stnkmg ~rrevers~bd~ty w=th cycles =n the apphed field The Fraunhofer related/c(B) curve =s d=splaced m B and the maximum / c reduced The magmtude of the shift depends on the maximum value of B =n the cycle and vanes w~th smtermg temperature and =mpur=ty content An mterpretat=on of the complex dependence of cnt~cal current on apphed field and sample m~crostructure ~s g~ven =n terms of the hysteret~c propert=es of a Josephson lunct~on network mediated by trapped flux wh=ch =s retained by strong pmmng reg=ons