Transmission electron-microscope images of transverse sections of films with a comparatively low magnification (approximately ). The films were deposited by pulsed laser ablation on a (100) substrate. a—substrate temperature , the subboundaries are of a diffuse, disordered character, and the size of the domains is ; b—substrate temperature , one can see domains separated from each other by well-formed ordered dislocation subboundaries; stacking faults with a domain size of can also be seen, (c) a schematic illustration of a typical nanostructure of domains in a film; also shown are threading edge dislocations in the subboundaries.
Critical current density as a function of the applied perpendicular field, measured at different temperatures with the aid of a SQUID magnetometer for film sample K1509 (off-axis dc magnetron sputtering, thickness ). The data from measurements by the transport method at are shown for comparison.
Schematic illustration of a 1° low-angle subboundary. The “windows” for the flow of supercurrent between the normal cores are shown. A distance between dislocations of corresponds to a misorientation angle of 1°.
Schematic picture of rectangular domains and the triangular Abrikosov vortex lattice. Shown are the characteristic sizes that are important for the model of limitation of on account of depinning of vortices from conditions in low-angle domain subboundaries.
Calculated dependence of on the dimensionless parameter at different values of , i.e., upon a change of the accomodation function . The straight lines correspond to the approximation .
Reduced field dependence of the critical current for a film obtained by off-axis magnetron sputtering on a sapphire∕ substrate. The solid line is a combined fit of the experimental data for 10, 30, and . The dashed lines are the calculated curves for a broad distribution and for “solid” (continuous) boundaries ; is the reduced distance between dislocations.
Model size distribution functions of the domains (the integral is normalized to unity). The value corresponds to the position of the peak. The experimental results correspond to .
Fourier transform of the diffraction function for the reflections (1 0 6) and (2 0 12) for a YBCO film grown by magnetron sputtering on a sapphire∕ substrate; is the parameter of the Fourier transformation.
Plots of (squares) and (triangles) for the film sample K2 ( thick, obtained by magnetron sputtering) at , measured by the magnetic susceptibility method immediately after cooling (filled symbols) and after thermocycling between 77 and (unfilled symbols).
Plots of (filled symbols) and (unfilled symbols) for film sample K6300 ( thick, obtained by magnetron sputtering) at , measured by the four-probe transport method.
Plots of for the film sample K34-2 ( thick, grown by magnetron sputtering) for different orientations of the magnetic field: the symbols are experimental, the curves, calculated.
Bending of vortices partially pinned on edge dislocations. Left: completely pinned vortex; for a parallel field does not penetrate into the film. Right: a vortex with partially depinned ends at .
Angle dependence of for film sample K2 for three values of the applied magnetic field. Angular hysteresis at a field of : the filled and unfilled symbols are the ascending and descending branches, respectively, and is the angle between and the axis.
Angular hysteresis of the critical current at an intermediate value of the applied magnetic field for the film sample K2.
Calculated evolution of the angle dependence with increasing applied magnetic field from . Some of the curves were obtained from measurements of under direct variation of the orientation of the film with respect to the field vector, while others are data interpolated with the use of the curves measured for the same film at various fixed values of .
Article metrics loading...
Full text loading...