PECULIARITIES OF VORTEX PHASES IN RARE-EARTH SUPERCONDUCTORS

The spin-flop or metamagnetic transition in antiferromagnetic rare earth (RE) superconductors may lead to the appearance of a magnetic domain structure with modulated vortex density. Near the vortex core a ferrimagnetic region could be formed and under appropriate conditions peculiar two-quanta vortices may be stable. The anisotropy of the magnetic RE subsystem substantially influences the intervortex interaction: in the RE superconductors with an easy axis magnetic anisotropy the flux lines attract each other at large distances if they are inclined with respect to the anisotropy axis. In this case the tilted lower critical field corresponds to the penetration of a vortex chain into the sample, rather than a single vortex.