Transverse-field components of the flux-line lattice in the anisotropic superconductorYBa2Cu3O

Observations of the configuration of the high-field vortex lattice inYBa2Cu3O7: Dependence upon temperature and angle of applied field

“…4͒. Both of these ratios may be deduced from the expression for the form factor in the presence of basal-plane anisotropy, which can be calculated from London theory 18,53 …”

“…As a bulk probe, it is unaffected by the systematics of surface-sensitive techniques. Being a diffraction technique, SANS is sensitive to spatial correlations of the vortices, making it highly suited to a diverse range of vortex matter studies including VL melting, 10 flux flow, 11 a range of studies on YBa 2 Cu 3 O 7−␦ that include investigations of twin-plane pinning, [12][13][14][15][16][17][18][19] and studies designed to probe the effect of disorder on the VL. [20][21][22] In the present context of unconventional VL structures and VL phase transitions, SANS continues to be a fecund source of information and a useful test bed against which to compare theory: recent examples in this area include borocarbides, 23 strontium ruthenate, 24 heavy-fermion materials, 25 and both electron-and hole-doped [26][27][28] high-T c materials.…”

Simultaneous evidence for Pauli paramagnetic effects and multiband superconductivity inKFe2As2by small-angle neutron scattering studies of the vortex lattice

“…For more than half a century small-angle neutron scattering (SANS) has been used to study the vortex lattice (VL) in a wide range of materials, [17][18][19][20][21][22] and has provided often unique information about gap nodes and dispersion, 6,[23][24][25] non-local effects, 26,27 multiband superconductivity, 28 Pauli paramagnetic effects, [29][30][31][32] and a direct measure of the intrinsic superconducting anisotropy (Γ ac ). [32][33][34][35][36][37][38] The latter quantity may be directly measured by the field-angledependent distortion of the VL structure (Γ VL ) from a regular hexagonal pattern. In London theory Γ ac represents the anisotropy of the penetration depth.…”

Eilenberger and London theories for transverse components of flux line lattice form factors in uniaxial superconductors

“…In this paper, we investigate the magnetic field orientation dependence of the transverse and the longitudinal components of the FLL form factors for the material parameters appropriate to YBa 2 Cu 3 O 7−δ [8]. We perform the calculations by two methods of the Eilenberger theory and the London theory, comparatively.…”