Vortex structure in ferromagnetic superconductors

It is shown that in ferromagnetic superconductors the polarization of the local spins induced by the persistent current in a vortex is quantized along with the magnetic field due to the current. Because of the polarization the vortex structure strongly depends on temperature. Near the ferromagnetic transition temperatures TM all the superconductors become type I even if they are extremely of type II far above TM. © 1979.