Scaling of pinning forces in NdBa2Cu3O7−δ superconductors

Abstract

Articles you may be interested inColumnar tilt and vortex stress in superconducting thin films of Nd Ba 2 Cu 3 O 7 − δ : Magnetization critical current-density measurementsThe scaling of the volume pinning forces, F p ϭ j c ϫB a , is performed versus the reduced fields b f ϭB a /B fp ͑where B a is the applied field, and B fp denotes the peak position of F p,max ) and h ϭH a /H irr ͑where H irr denotes the irreversibility field͒ for two different NdBa 2 Cu 3 O 7Ϫ␦ superconductors, a single crystal and a melt-processed sample. In both cases, an excellent natural scaling is found to hold. Based on these good scaling results, we extend the scaling analysis towards lower temperatures. There, the scaling parameters are no longer directly accessible within our experimental field range, but can be deduced from the F p (B a ) curves normalized using fitting values of B fp and F p,max so that these overlap with the high temperature curves. It is shown that such a procedure allows to obtain reasonably good estimates of F p,max and H irr , which leads in turn to an estimation of the irreversibility line well down to 0 temperature. At low temperatures, deviations from the analytical dependencies appear which are due to interference with the central and intermediate peak in the magnetization loops. The shape of the irreversibility line is discussed.

Doping dependence of the vortex dynamics in single-crystal superconducting NaFe${}_{1-x}$CoxAs

“…However, these values do not agree with any single model for flux-pinning mechanisms introduced by Dew-Hughes. Similar values of the exponents have been reported for cuprate high-T c superconductors such as YBa 2 Cu 3 O 7 (p = 2.48, q = 3.56, h = 0.33), NdBa 2 Cu 3 O 7 (p = 1.48, q = 2.23, h = 0.45) and Sm 0.5 Eu 0.5 Ba 2 Cu 3 O d -7 [38,[51][52][53]. Furthermore, a table with values of p and q for most of the iron-based compounds can be found in [54].…”

The collective flux pinning force in (Sm0.5Eu0.5)Ba2Cu3O7−δsuperconductors

“…The flux pinning mechanism is not definitely established. The scaling of the normalized pinning force density versus reduced applied magnetic field gave varied values of the parameters p and q, indicating the type of flux pinning mechanism, in the MTG RE123 samples [13][14][15][16][17][18]. In order to know what the effective pinning centre is in our samples, we also scale the flux pinning force at several temperatures in the following.…”

The flux pinning force and vortex phase diagram of single crystal

“…NdBa 2 Cu 3 O 7- (p=1.48, q=2.23, h max =0.45); YBa 2 Cu 3 O 7 (p=2, q=4, h max =0.33), and Sm 0.5 Eu 0.5 Ba 2 Cu 3 O 7- (p=2.08, q=3.56, h max =0.37). [14][15][16] The value of h max ~0.28, for our FeTe 0.60 Se 0.40 single crystal. Dew Hughes has propounded a model where h max =0.2 and 0.33 correspond to the surface pinning and the point core pinning respectively.…”

“…Similar scaling was also found to valid in the case of unconventional high temperature superconductors (HTSC), with h=H/H irr , where H irr is the irreversibility field. [13][14][15] The H irr is taken as the value of applied magnetic field, where J c (T,H) becomes too small to be useful for any practical application.…”