  We review our recent results on ferromagnetic superconductors, URhGe and
UCoGe. High quality single crystals of both compounds were successfully grown.
The specific heat shows a clear jump related to the superconducting transition
in UCoGe. The finite values of C/T at 0K are discussed in terms of the
self-induced vortex state and the value of the ordered moment. With increasing
fields for H // b-axis in URhGe, the jump of thermal expansion increases and
shifts to lower temperature. The re-entrant and S-shaped superconducting phases
for URhGe and UCoGe respectively are explained by the unusual field dependence
of the effective mass, which is induced by the ferromagnetic instability when
the field is applied along the hard magnetization b-axis. The magnetic
fluctuations are very sensitive to the field orientation. This is reflected in
the Hc2 and the anisotropy of the effective mass.
