Non-logarithmic flux creep in Bi-2212

✍ Scribed by A Spirgatis; R Trox; J Kötzler; J Bock

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 305 KB
• Volume: 33
• Category: Article
• ISSN: 0011-2275
• DOI: 10.1016/0011-2275(93)90092-3

✦ Synopsis

The decay of the remanent magnetizations of crystalline (MIIc) and ceramic Bi2Sr2CalCu208 have been measured between 1 s and 2 × 104 s for temperatures between 4 K and 20 K. With increasing temperature the long-time relaxation M(t, T) becomes significantly non-logarithmic, which, following a suggestion by Maley et al., we formally relate to an effective activation energy Ueff. We can describe this barrier by the simple law Ueff(M)= U o In(Mo/M), which corresponds to an algebraic flux creep, M(t, T)/Mo = (t/to)-%T/Uo. The activation energies are Uo = 8(1) meV for the crystal and 20(3) meV for the ceramic. According to the recent theories by Vinokur et al., this behaviour may be associated with pinning of single 3D vortices.