ISSN:
1434-6036
Keywords:
74.60Ge
;
74.76Bz
;
61.80Jh
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract The nature of dissipative flux motion in epitaxial YBa2Cu3O7−δ thin films has been investigated by means of resistivity ϱ(T, B) and transport current-voltage characteristicsE(j, T, B) covering up to 5 orders of magnitude in voltage for a wide range of temperatures (4.2–85 K) and magnetic fields (0.5–7.0 T). Activation energiesU(T, B, j) have been determined in the framework of the collective flux creep theory. It is shown thatU(T, B, j) decreases with increasing temperature, magnetic field and current density. In order to study the influence of a well-defined defect structure, columnar defects have been generated by irradiation with 340 MeV Xe-ions. From a scaling law relating theI–V curves after irradiation with the curves before irradiation it is found that vortices pinned by the columnar defects do not contribute to dissipation. Due to irradiation the irreversibility line is shifted to higher magnetic fields, indicating its connection to the pinning mechanisms present in the samples.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01312172
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