Abstract
This paper is devoted to exotic coexistence ferromagnetism and superconductivity of UCoGe compound and also magnetism of U3Co4Ge7 compound. U3Co4Ge7 compound is ferromagnet with Tc = 21 K and complex crystal structure.
Strong sample state dependence of physical behavior was observed in the case of UCoGe compound. While UCoGe as-cast sample was paramagnetic and hint of superconductivity occurred at 0.4 K the annealed sample was superconductor at Tsc = 0.7 K in strong spin fluctuation regime.
The UCoGe behaviour is discussed on the basis of critical ferromagnetic spin fluctuations.