Transport properties and flux pinning by self-organization in YBa2Cu3O7−δ

Anisotropic nonmonotonic behavior of the superconducting critical current in thinYBa2Cu3O7−δCantoni1, Verebelyi2, Specht3 et al. 2005Phys. Rev. B203161View full textAdd to dashboardCite

“…In this sense the tape surface is naturally vicinal, and since texture is obtained by high-temperature anneal of the metal substrate, unit-cell-high steps are expected on the epitaxial oxide buffer layers deposited on them. Several studies have documented that when YBCO grows on a stepped STO surface, unit cells nucleating on adjacent terraces can be out of register because they are shifted vertically with respect to each other by a fraction of the YBCO unit cell [1,[10][11][12][13][14]. This situation induces an extended planar defect in the YBCO film which is referred to as antiphase boundary (APB).…”

“…It has been found that steps induced on the substrate surface by a miscut angle ψ between the c-axis and the surface normal, are responsible for a variety of peculiar phenomena in the YBCO films deposited on such substrates. These effects include modifications of the type of defects associated with the film lattice [1,2], 3 anisotropy of the in-plane critical current density (J c ) [3][4][5], changes in the distribution of twin domains due to increased interfacial strain [6], vortex channeling effects [7], and change in the c-axis tilt of the YBCO film. Among others, Haage, and Jooss [1] have nicely documented the morphology of carefully reconstructed vicinal STO surfaces and the microstructure of the YBCO films grown of such surfaces.…”

“…These effects include modifications of the type of defects associated with the film lattice [1,2], 3 anisotropy of the in-plane critical current density (J c ) [3][4][5], changes in the distribution of twin domains due to increased interfacial strain [6], vortex channeling effects [7], and change in the c-axis tilt of the YBCO film. Among others, Haage, and Jooss [1] have nicely documented the morphology of carefully reconstructed vicinal STO surfaces and the microstructure of the YBCO films grown of such surfaces. They focused on vicinal angles of ~ 10° towards the [100], which expose the (106) plane of STO, and reported significantly enhanced critical currents for conduction along the step ledges (longitudinal direction, or L).…”

Nanotechnologies to Enable High‐Performance Superconductors for Energy Applications

“…The defects targeted by this study were threading edge and screw dislocations normally occurring during the YBCO growth process, especially in PLD films with their columnar growth mode. Subsequently, another type of strong, naturally occurring, pinning defects, known as antiphase boundaries, were studied in detail using controlled vicinal substrate surfaces to tailor their density [29,30]. Figure 6 shows a collection of various defects usually occurring in YBCO films as imaged by high resolution transmission electron microscopy (HRTEM).…”

Substrate surface engineering for tailoring properties of functional ceramic thin films

“…The planar APBs are oriented perpendicular to the film plane forming a regular nanoscale array with an APB distance of around 7 nm. A detailed analysis of the defect structure due to the nanoscale surface step structure of the substrate and its implications to transport properties and flux pinning is given in by Haage et al [16]. The predominant modifications of the properties of such films are summarized as follows [17]: (i) Strong anisotropy of the electrical dc resistivity; (ii) thickness dependent enhancement of the critical current; (iii) partial detwinning of the films with a better perfection of the CuO chains along the step edges; (iIV) anisotropy of the dimensionality of the fluctuation conductivity above T c with a large temperature range for the 3-dimensional fluctuations along the step edges and a small range for 3-dimensional fluctuations perpendicular to the step edges.…”