  The NMR measurements performed on a single orthorhombic crystal of
superconducting ferromagnet UCoGe (Y.Ihara et al, Phys. Rev. Lett. v.105,
206403 (2010)) demonstrate strongly anisotropic magnetic properties of this
material. The presented calculations allow to establish the dependence of
longitudinal spin-lattice relaxation rate from temperature and magnetic field.
The value 1/T_1T in field perpendicular to spontaneous magnetisation directed
along c-axis has maximum in vicinity of Curie temperature whereas it does not
reveal similar behaviour in field parallel to the direction of spontaneous
magnetisation. Also there was shown that the longitudinal spin-lattice
relaxation rate is strongly field dependent when the field directed in
b-crystallographic direction but field independent if magnetic field is
oriented along a-axis.

Strongly Correlated Electrons