Magnetism and superconductivity in ErNi2B2C

摘要

We have performed a series of neutron diffraction experiments from the magnetic order and the vortex lattice in single crystal ErNi2B2C. The incommensurate magnetic structure develops additional even harmonics below the `ferromagnetic' ordering temperature, e?‘?F of 2.3 K. This feature and the existence of rods of diffuse scattering suggest the development of ferromagnetic microdomain walls. The magnetic structure is very sensitive to the application of a magnetic ???eld with changes in modulation vector and harmonic content. Studies of the vortex lattice show the presence of a 45?° reorientation transition and a distorted hexagonal to square transition as a function of applied ???eld. Further distortions of the vortex lattice occur at e?‘?N, but no changes are seen at e?‘?F.