On anisotropy of resistance in the basal plane of YBa2Cu3O<i>x</i> single crystals in a magnetic field
Abstract
Resistive transitions are investigated for different orientations of a magnetic field in the ab plane for orthorhombic YBaCuO single crystals with twins. It is shown that the anisotropy of resistance in the basal plane observed for such single crystals can be explained in analogy with resistance anisotropy induced by a magnetic field in HTS polycrystals. This anisotropy is a consequence of anisotropy in the conductivity and field Hc2 in the ab plane due to the presence of highly conducting CuO chains in orthorhombic crystals. In view of peculiarities in its symmetry, the observed anisotropy cannot be explained by the effect of twinning planes or magnetic flux creep. Single crystals with a low oxygen content containing no chains do not exhibit any anisotropy or R in the basal plane.