Films and surfaces of ferromagnetic superconductors

The ternary compounds such as (RE)Rh₄B₄ and (RE)Mo₆S₈ contain magnetic rare earth ions RE at the regular lattice sites, nevertheless they show superconductivity. In the superconducting state of films and surfaces of these compounds, the interplay between magnetism and superconductivity causes the following unusual phenomena: the magnetization bound within the London penetration depth from the surface appears below a critical temperature. In the films various types of the magnetic orders coexisting with superconductivity appears depending on the film thickness. The anomalous behavior of the Josephson effect in ferromagnetic superconductors is briefly discussed.