Determination of critical current densities of YBa2Cu3O7−δ thin films from AC susceptibility measurements

Xing, Weirong; Heinrich, B.; Chrzanowski, J.; Irwin, J. C.; Zhou, Hua; Cragg, A.; Fife, A. A.

doi:10.1016/0921-4534(93)90397-9

Cited by 42 publications

(23 citation statements)

References 20 publications

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“…The superconducting sample is fully inserted in the pick-up coil, where the induced signal is measured. An alternative technique that has been used is the screening technique, 2,4,6,7,13 in which a superconducting sample is sandwiched between two coils. In this case the excitation field is not uniform in the sample.…”

Section: Introductionmentioning

confidence: 99%

“…[1][2][3][4][5][6][7][8][9][10] With this technique it is possible to study Josephson tunneling 11 and vortex states, 12 determine the critical current density (J c ), 3,4,7 etc. In this technique, the pick-up and compensation coils are connected in series and placed coaxially inside a solenoid that generates a homogeneous ac field in its interior.…”

Section: Introductionmentioning

confidence: 99%

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Screening technique measurement of ac imaginary susceptibility and critical current density of YBa2Cu3O7−δ films

Acosta

Sosa

et al. 2000

Journal of Applied Physics

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The screening technique was used to study systematically the ac susceptibility of superconducting YBa2Cu3O7−δ thin films in the temperature range of 32–83 K. We used the Fourier transform of the pick-up signal, coming from the secondary coil, to estimate the critical current density. From the experimental data we observed regularities in the imaginary part of ac susceptibility, and confirmed that the flux creep mechanism is dominant.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Screening technique measurement of ac imaginary susceptibility and critical current density of YBa2Cu3O7−δ films

Acosta

Sosa

et al. 2000

Journal of Applied Physics

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“…Therefore, the caution should be taken when one uses the critical state model to determine J c from ACS measurements, especially for J c (T) by increasing H a and thus decreasing T p , as employed in many groups. 10,11 In conclusion, a scaling law has been obtained for temperature dependencies of ACS in an ac field range from 0.22 to 30.8 G ͑square root values͒. The critical state model can be used to account for the ACS only below the irreversibility line, which is characterized as the peak position of the imaginary part of ACS.…”

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confidence: 98%

“…This behavior of ACS is in good agreement with that reported by other groups. 10 Figure 2 gives the H a dependence of the Ј onset (T conset ) and Љ peak (T p ) temperatures. It is obvious that T p is much more sensitive to the field H a than T conset .…”

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confidence: 99%

A scaling law for ac susceptibility of an YBa2Cu3O film in a perpendicular ac field

Han

Ong

et al. 1997

Applied Physics Letters

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The ac susceptibility (ACS) of an YBa2Cu3O thin film in a perpendicular ac magnetic field (Ha) from 0.22 to 30.8 G is measured as a function of temperature. The temperature dependence of the real (χ′) and imaginary (χ′′) parts of the ACS for various Ha can be well scaled onto a single curve using the peak value (χp″) and temperature (Tp) of χ′′(T) as the scaling parameters. The scaling law suggests that the critical state can be established only below Tp. Above Tp, the ACS is determined by the screening effect of the film due to the sharp decrease of its resistance. Below Tp, the scaling behavior is in agreement with the theoretical approaches based on the critical state model, only if the temperature for zero critical current density is related to the irreversibility temperature Tirr rather than Tc. From the scaling law, we found that Tirr=Tp.

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“…He proposed that H p is the value associated with the highest peak in the ratio χ 3 (H ac )/χ 1 (H ac ) max . We also add the criterion of Xing et al [5], based on the measurement of the maximum of χ 1 (T ). Under this method the critical current density is found to be …”

Section: The Sun Model and Experimentalmentioning

confidence: 99%

Critical current density and ac harmonic voltage generation in YBa2Cu3O7-δ

Pérez-López

Gamboa

Sosa

2010

Physica C: Superconductivity and its Applications

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The temperature and field dependence of harmonics in voltage V n = V n − iV n using the screening technique have been measured for YBa 2 Cu 3 O 7−δ superconducting thin films. Using the Sun model we obtained the curves for the temperature-dependent critical current density J c (T ). In addition, we applied the criterion proposed by Acosta et al. to compute J c (T ). Also, we made used of the empirical law J c ∝ (1 − T /T c ) n as an input in our calculations to reproduce experimental harmonic generation up to the fifth harmonic. We found that most models fit well the fundamental voltage but higher harmonics are poorly reproduced. Such behavior suggests the idea that higher harmonics contain information concerning complex processes like flux creep or thermally assisted flux flow.

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Determination of critical current densities of YBa2Cu3O7−δ thin films from AC susceptibility measurements

Cited by 42 publications

References 20 publications

Screening technique measurement of ac imaginary susceptibility and critical current density of YBa2Cu3O7−δ films

Screening technique measurement of ac imaginary susceptibility and critical current density of YBa2Cu3O7−δ films

A scaling law for ac susceptibility of an YBa2Cu3O film in a perpendicular ac field

Critical current density and ac harmonic voltage generation in YBa2Cu3O7-δ

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