Neutron scattering study of the effects of dopant disorder on the superconductivity and magnetic order in stage-4 La2CuO4+y
Journal
Physical Review B - Condensed Matter and Materials Physics
Journal Volume
69
Journal Issue
2
Date Issued
2004
Author(s)
Abstract
We report neutron scattering measurements of the structure and magnetism of stage-4 La2CuO4+y with Tc≃42K. Our diffraction results on a single crystal sample demonstrate that the excess oxygen dopants form a three-dimensional ordered superlattice within the interstitial regions of the crystal. The oxygen superlattice becomes disordered above T≃330K, and a fast rate of cooling can freeze in the disordered-oxygen state. Hence, by controlling the cooling rate, the degree of dopant disorder in our La2CuO4+y crystal can be varied. We find that a higher degree of quenched disorder reduces Tc by ∼5K relative to the ordered-oxygen state. At the same time, the quenched disorder enhances the spin-density wave order in a manner analogous to the effects of an applied magnetic field. © 2004 The American Physical Society.
Type
journal article