Onset of ferromagnetism in the 5f-band metamagnet UCoAl upon partial dilution of the U sublattice

AC and dc magnetic susceptibility measurements have been carried out after annealing under an appropriate condition for Y6 (Mn1-xFex)23 compounds with x=0.50, 0.55 and 0.60. At low temperatures, the onset of a spin–glass state has been confirmed in contrast with the existing data. It is concluded that the blocking of antiferromagnetic clusters claimed in previous studies is attributed to compositional inhomogeneity.