Logarithmic U(j) relationship in melt-textured growth YBa2Cu3O6+x by AC susceptibility measurements

✍ Scribed by M.J. Qin; S.Y. Ding; C. Ren; X.X. Yao; Y.X. Fu; C.B. Cai; T.S. Shi; G.Y. Wang

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 539 KB
• Volume: 262
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/0921-4534(95)00381-9

✦ Synopsis

Complex AC susceptibility measurements have been performed systematically on a melt-textured growth YBa2Cu206+ sample. The activation energy has been determined to be U(T, H, j)= Uo[1-(T/Tx)2]3/2(Ho/H)n ln(jo/j), with n = 0.46 and n ~ 0.59 for H II ab and H II c, respectively. The expressions U(H) ~ H -°5 and U(j) ~ ln(jo/j) obtained by the AC technique in this work agree basically with those observed in YBa2Cu307 samples by transport or magnetic measurements, which may result from vortex pinning by the planar defects in the sample. We have also shown that the limited time window in conventional magnetic-relaxation measurements can be extended to much smaller values by the AC technique, which is in the range of 4× 10 -5 s-3 x 10 -3 s in this work.