Softer than normal, but not as soft as one might think: Spontaneous flux   lattices in ferromagnetic spin-triplet superconductors
  A theory is developed for the spontaneous vortex lattice that is expected to occur in the ferromagnetic superconductors ZrZn_2, UGe_2, and URhGe, where the superconductivity is likely of spin-triplet nature. The long-wavelength fluctuations of this spontaneous flux lattice are predicted to be huge compared to those of a conventional flux lattice, and to be the same as those for spin-singlet ferromagnetic superconductors. It is shown that these fluctuations lead to unambiguous experimental signatures which may provide the easiest way to observe the spontaneous flux lattice. 
Sumanta Tewari, D. Belitz, T.R. Kirkpatrick, and John Toner