  UCoGa and URhGa, two isostructural compounds show opposite signs of the
initial response of Curie temperature to applied hydrostatic premenssure. To
determine the physical origin of this contradiction the magnetization data
measured with respect to temperature, magnetic field and hydrostatic pressure
were analyzed in the framework of the Takahashi's spin-fluctuation theory. The
parameters T0 and TA characterizing the distribution widths of the
spin-fluctuation spectrum in the energy and wave vector space, respectively,
and TC/T0, the degree of the 5f-electron localization have been determined.
Examination of available experimental data for the other UTX (T = a transition
metal, X = Al, Ga) ferromagnets having the ZrNiAl-type structure revealed some
correlations between the degree of the 5f-electron localization represented by
the spin-fluctuation parameters and the response of Curie-temperature on the
applied pressure. These observations may be applied more generally to describe
the localization and magnetic behaviors of the majority of the uranium
ferromagnetic compounds.
