Thermally activated depinning of individual vortices in YBa2Cu3O7 superconducting films

Pan, Alexey V.; Zhao, Yue; Ionescu, Mihail; Dou, Shi Xue; Komashko, V. A.; Flis, V. S.; Pan, V. M.

doi:10.1016/j.physc.2004.05.008

Cited by 23 publications

(29 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This technique shows visually the position of cracks [5,8], weak links [4,6,7] and other micro-and macroscopic defects in the sample [2,9], however there may be other current-limiting mechanisms that are not so readily visible at the macroscopic scale nor directly dependent on critical current density [10,11].…”

Section: Introductionmentioning

confidence: 99%

Dynamic magneto-optical imaging of superconducting thin films

Wells

Pan

Wilson

et al. 2016

Supercond. Sci. Technol.

View full text Add to dashboard Cite

We present a novel method for analysis of superconducting thin films using dynamic magneto-optical imaging, revealing hallmarks of flux penetration with temporal resolution around 1 ms (in the present work) or better. This method involves investigation of transient field and dynamic current distributions, which are calculated by an inversion procedure on the Biot-Savart Law, which we show to be valid under dynamic conditions. We compare and discuss the flux front penetration speed and evolution of current distribution in high quality YBa2Cu3O${}_{7-\delta }$ thin films with that of samples deliberately damaged in such a way as to reduce critical current density without causing macroscopic damage. We present a novel method for analysis of superconducting thin films using dynamic magnetooptical imaging, revealing hallmarks of flux penetration with temporal resolution around 1 ms (in the present work) or better. This method involves investigation of transient field and dynamic current distributions, which are calculated by an inversion procedure on the Biot-Savart Law, which we show to be valid under dynamic conditions. We compare and discuss the flux front penetration speed and evolution of current distribution in high quality YBa2Cu3O7−δ thin films with that of samples deliberately damaged in such a way as to reduce critical current density without causing macroscopic damage.

show abstract

Section: Introductionmentioning

confidence: 99%

Dynamic magneto-optical imaging of superconducting thin films

Wells

Pan

Wilson

et al. 2016

Supercond. Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…Note, B * can be defined as the field at which the critical current reaches the 90% 79 or 95% 77,78 of the value obtained for zero applied field. However, in this work it is sufficient to qualitatively demonstrate that B * is the transition from a plateau-like J c (B a ) dependence to the power-law dependence and is directly proportional to dislocation density (as well as to the island density at any thickness of the film) 61,77 . The characteristic field B * increases with increasing laser frequency [ Fig.…”

Section: B Ybco Thin Filmsmentioning

confidence: 82%

“…61 . This field, denoting transition from the single vortex pinning regime at low fields to a collective pinning regime at higher fields, can be used to accurately determine the pinning radius of the individual vortex pinning 77,78 . Note, B * can be defined as the field at which the critical current reaches the 90% 79 or 95% 77,78 of the value obtained for zero applied field.…”

Section: B Ybco Thin Filmsmentioning

confidence: 99%

“…7] (note, this trend is independent of the B * definition). The B * increase indicates enhanced pinning and reduction of the individual depinning radius 77,78 . As B * is proportional to the dislocation density (dominating pinning in PLD YBCO films), it is natural to expect an enhancement of J c (B a ) consistent with the B * enhancement that is clearly the case, as can be seen in Fig.…”

Section: B Ybco Thin Filmsmentioning

confidence: 99%

“…The quantitative agreement between densities of dislocations and islands, as well as B * , J c (B a ) and J c (0) may be not easy to find 77 because while B * is determined by density of pinning centres in single vortex pinning regime, J c (0) is established by strength of individual pinning cites 28 . In addition, other effective pinning defects 77,78 , such as twin boundaries 26,81 , oxygen vacancies 82 and Y 2 O 3 inclusions 83,84 are present and can be affected by deposition frequency. Indeed, smoother transitions at the higher deposition frequencies from the plateau-like J c (B a ) dependence at B a → 0 to the powerlaw dependence at the larger fields [insert in Fig.…”

Section: B Ybco Thin Filmsmentioning

confidence: 99%

See 2 more Smart Citations

Significant tunability of thin film functionalities enabled by manipulating magnetic and structural nano-domains

Golovchanskiy

Pan

Fedoseev

et al. 2014

Applied Surface Science

View full text Add to dashboard Cite

The influence of laser frequency on the structure and physical properties of thin films grown by pulsed laser deposition has been studied. Different types of thin films, hard ferromagnetic FePt L10 and quasi-single crystal superconducting YBa2Cu3O7 (YBCO), have been used for demonstration of the effect. Significant structural modifications have been obtained for the films with similar thicknesses. These modifications are shown to dramatically control their corresponding properties, providing an instrumental ability for tuning the practical characteristics of the films by changing the laser frequency of their deposition. In particular, 20-fold increase of coercive field and modification of demagnetization mechanism are obtained for FePt films by varying the frequency from 1 Hz to 6 Hz. Over a similar frequency range, a strong dependence on the laser frequency is discovered for the YBCO films for the critical current density behavior as a function of the applied magnetic field [ Jc(Ba)] with the unexpected reversal of Jc(Ba) curves with temperature. The mechanisms of structure modifications and corresponding property variations are proposed. The influence of laser frequency on the structure and physical properties of thin films grown by pulsed laser deposition has been studied. Different types of thin films, hard ferromagnetic FePt L10 and quasi-single crystal superconducting YBa2Cu3O7 (YBCO), have been used for demonstration of the effect. Significant structural modifications have been obtained for the films with similar thicknesses. These modifications are shown to dramatically control their corresponding properties, providing an instrumental ability for tuning the practical characteristics of the films by changing the laser frequency of their deposition. In particular, 20-fold increase of coercive field and modification of demagnetization mechanism are obtained for FePt films by varying the frequency from 1 Hz to 6 Hz. Over a similar frequency range, a strong dependence on the laser frequency is discovered for the YBCO films for the critical current density behaviour as a function of the applied magnetic field [Jc(Ba)] with the unexpected reversal of Jc(Ba) curves with temperature. The mechanisms of structure modifications and corresponding property variations are proposed.

show abstract

Tunable pinning effects produced by non‐uniform antidot arrays in YBCO thin films

et al. 2017

View full text Add to dashboard Cite

Uniform, graded and spaced arrays of 3 μm triangular antidots in pulsed laser deposited YBa 2 Cu 3 O 7 (YBCO) superconducting thin films are compared by examining the improvements in the critical current density J c they produced. The comparison is made to establish the role of their lithographically defined (non-)uniformity and the effectiveness to control and/or enhance the critical current density. It is found that almost all types of non-uniform arrays, including graded ones enhance J c over the broad applied magnetic field and temperature range due to the modified critical state. Whereas uniform arrays of antidots either reduce or produce no effect on J c compared to the original (asdeposited) thin films.

show abstract

Thermally activated depinning of individual vortices in YBa2Cu3O7 superconducting films

Cited by 23 publications

References 24 publications

Dynamic magneto-optical imaging of superconducting thin films

Dynamic magneto-optical imaging of superconducting thin films

Significant tunability of thin film functionalities enabled by manipulating magnetic and structural nano-domains

Tunable pinning effects produced by non‐uniform antidot arrays in YBCO thin films

Contact Info

Product

Resources

About