Abstract
We have used the technique of small-angle neutron scattering to observe magnetic flux lines directly in a single crystal at fields higher than previously reported. For field directions close to perpendicular to the planes, we find that the flux lattice structure changes smoothly from a distorted triangular coordination to nearly perfectly square as the magnetic induction approaches 11 T. The orientation of the square flux lattice is as expected from recent -wave theories but is from that recently observed in .
- Received 21 August 2003
DOI:https://doi.org/10.1103/PhysRevLett.92.067004
©2004 American Physical Society