Extraction of anisotropic critical current densities and flux pinning potentials

✍ Scribed by H.L Ji; Z.X Shi; Z.Y Zeng; X Jin; H.C Fan; X.X Yao; X.S Rong; Y.M Ni; Z.X Zhao

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 482 KB
• Volume: 34
• Category: Article
• ISSN: 0011-2275
• DOI: 10.1016/0011-2275(94)90114-7

✦ Synopsis

Magnetic measurements were performed on an MTG YBa2Cu306+x sample at three field orientations. An extended Bean model was used to extract the anisotropic critical current densities. Compared with the corresponding magnetic measurement at the Hllab plane, the anomalous increase of calculated Jab, ab (critical current density flowing in the ab plane at H_Lc-axis) with the applied field is much more clear, and its field dependence is similar to that of magnetization hysteresis at HIIc-axis. Moreover, from the magnetization relaxation measurements at Hllab the time dependences of Jab, ab and Jc, ab (critical currents flowing along the c-axis at Hllab plane) were derived and used to determine the two corresponding effective activation energies for flux motion. Both of the current density dependences can be fit with the power law but with different exponents, which may provide a possible explanation of the stronger temperature dependence of Jab, ab than Jc, ab.