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Critical current magnetic field dependence

Current-Voltage, I(V), characteristics were also measured on the same unstructured film in the presence of a magnetic field applied perpendicularly to the sample surface for two different temperatures. The critical current is defined by the arbitrary electric field criterion E = Ecr= 10 V/cm. Fig. 2 shows the resulting magnetic field dependence of the critical current, I. The film shows the usually reported monotonic field dependence of Ic. The expected enhancements of the critical current for fields values close to the first matching field, H] a 1 Tesla, for T = 3.1 K was not detected. This result could be ascribed to the... [Pg.222]

Critical current density also depends on magnetic field, decreasing monotonically to zero at the upper critical field Hc2 (16-17). In YBaCuO the slope of Hc2 with temperature is unusually large, of order 2 T/K when field is applied parallel to the predominant conduction planes of the structure (18-19). This implies record values (up to 200 T has been estimated) for the upper critical field at low temperatures and opens up the possibility of very high field magnets. [Pg.283]

Fig. 12.19. Magnetic field dependence at 77 K of the normalized critical current density for both in-plane directions of a (103) film is comparable to a high-/c c-3xis film. The effective magnetic field in the (103) film is (1/2) / because the superconducting Cu02 planes are at 45° to the substrate surface. Fig. 12.19. Magnetic field dependence at 77 K of the normalized critical current density for both in-plane directions of a (103) film is comparable to a high-/c c-3xis film. The effective magnetic field in the (103) film is (1/2) / because the superconducting Cu02 planes are at 45° to the substrate surface.
Wollman et al. (1993, 1995) reported detailed measurements of the magnetic field dependence of the Josephson critical current for Y123/Au/Pb junctions formed on Y123 crystals. The observed results of the dependences for the edge junction and the corner junction are as shown in fig. 28. Double peak stmetures were seen for the comer junction, as expected from equation (5), indicating that Y123 is a d-wave superconductor. [Pg.599]

Fig.tt.2-32 Critical current density on dependence on the phase transformation from tetragonal to orthorhombic applied magnetic field for a single crystal film and a sintered... [Pg.729]

Fig. 4.2-46 Magnetic field dependence of the critical current density of an epitaxial B12212 film for the B c and Bxc directions at 4.2 K and 60 K, respectively. /c(0,4.2) is the critical current density at 4.2 K in zero field [2.90]... Fig. 4.2-46 Magnetic field dependence of the critical current density of an epitaxial B12212 film for the B c and Bxc directions at 4.2 K and 60 K, respectively. /c(0,4.2) is the critical current density at 4.2 K in zero field [2.90]...
Shown in fig. 16 is the magnetic field dependence of the critical current density for the IBAD and RABiTS based YBCO coated samples recently produced at LANL and ORNL, respectively. These coated samples operated in the liquid nitrogen temperature range clearly outperform the metallic superconductors (NbTi, NbjSn) at 4.2 K. Furthermore, even in the worst field direction H c), and for temperatures below 65 K, the short sample YBCO coated conductors operated in a 8-tesla background field have at least an order of magnitude higher Jc than pre-commercial BSCCO-2223 wire with no applied field. [Pg.25]

Fig. 16. Magnetic field dependence of the critical current density for a range of short sample YBCO conductors produced using either IBAD or RABiT substrates. These data are compared with typical values obtained for NbTi and Nb3Sn wires at 4.2 K and for BSCCO, oxide-powder-in-tube wires at 77 K. From Hawsqr and Peterson (1996). Fig. 16. Magnetic field dependence of the critical current density for a range of short sample YBCO conductors produced using either IBAD or RABiT substrates. These data are compared with typical values obtained for NbTi and Nb3Sn wires at 4.2 K and for BSCCO, oxide-powder-in-tube wires at 77 K. From Hawsqr and Peterson (1996).
We plot in figure 2 the angular dependence of the critical current density JJJd, Jd is the critical current density when a magnetic field is applied parallel to the film surface. We note that JcI is independent of the angle 9. The solid circles are the experimental data obtained for YBa2Cu307.8 thin film at 10 T and 60 K. For comparison, the solid curve presents the theoretical values given by [8]... [Pg.160]

The strong inverse dependence of critical current density on magnetic field at 77 K is a limitation associated with Bi-2223 tape. This necessitates operation at lower temperatures for certain applications (e.g. electromagnets) when the cable is subjected to strong magnetic fields. This limitation does not arise with the (RE)BCO system and intensive efforts are being made to manufacture suitable tapes. [Pg.230]

Strobilism would then potentially exist in the molecule, waiting to be rendered observable by a developer (in the photographic sense of the word) which, in our case, is the external magnetic field. If strobilism is a potential property of the molecule at rest, it is conceivable that it must be directly dependent upon the electronic and geometrical characteristics of the molecule in the ground state, e.g. electron distribution, symmetry point group, and so on. We will see immediately how it is possible to verify this and in particular to support, from this viewpoint, Musher s criticism of the ring current concept. [Pg.43]

The preceding material may be used to characterize the thermodynamics of transitions from the normal to the superconducting state. This transformation takes place for a limited class of materials at a particular temperature Tc, currently below 140 K. For soft superconductors of type I this state is marked by a complete disappearance of electrical resistivity and by the fact that at moderate values the magnetic induction B = M. + AnH vanishes within the bulk of the sample, so that for such materials M = —AnH. However, as the field is increased a critical magnetic field He is reached beyond which the material reverts back to its normal state. In first approximation He depends only on temperature according to the relation... [Pg.344]

Figure 9 Dependence of the critical current on the external magnetic field from 21 K to 33 K, for the sample of Fig. 8. A clear phase shift of ix is observed at the same threshold temperature for which a minimum of the Josephson current is achieved. Figure 9 Dependence of the critical current on the external magnetic field from 21 K to 33 K, for the sample of Fig. 8. A clear phase shift of ix is observed at the same threshold temperature for which a minimum of the Josephson current is achieved.

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