Distance between vortices in a thin YBa2Cu3O7 film in parallel magnetic field

A direct measurement of the distance between the vortices was performed by neutron surface diffraction. The vortices were created by an external magnetic field Hext parallel to the surface of a thin YBa2Cu3O7 film. The behavior of the equilibrium vortex configurations in increasing Hext beyond the first critical field was studied. The distances between vortices within the vortex rows parallel to the sample surface were deduced from the positions of the Bragg-peaks measured in grazing incidence configuration GID for Hext=1.0 and 1.5T. The obtained values of the distance of 445 and 480A, respectively, belong to the equilibrium configurations with four and five vortex rows perpendicular to the film surface.