A SPIN-GLASS STATE IN THE ITINERANT MAGNET SYSTEMS Y(CO1-XMNX)2 AND LU(CO1-XMNX)2

Magnetic properties of the Y(Co1-xMnx)2 and Lu(Co1-xMnx)2 Laves phase systems are studied. Spin-spin correlations are found to increase as the Mn concentration increases from x = 0, and to pass over a maximum for x almost-equal-to 0.35. A spin-glass state is established within limited ranges of the Mn concentration x, bounded to almost-equal-to 0.04 less-than-or-equal-to x less-than-or-equal-to 0.4 in the Y based compounds and to almost-equal-to 0.04 less-than-or-equal-to x less-than-or-equal-to 0.5 in the Lu based compounds. Emphasize is made on the Stoner-character of the magnetism of the compounds, which should lead to a spin-glass state distinguishing itself by frozen longitudinal spin fluctuations below the spin-glass freezing temperature T(SG).