The spontaneous linear magnetostriction at T=0 K in YCo4B is positive along the a axis (?a
=1.1??10-3) and negative along the c axis (?c=-2.1??10-3), although the volume magnetostriction below Tc
is negligibly small and below the resolution of the x-ray measurement. In CeCo4B, however, both ?a and ?c
are smaller and below about 130 K, a negative volume magnetostriction of the order of 10-3 is observed. An
anomalous increase of the resistivity is also found at the same temperature range. This anomalous behavior
is assumed to be related with the Ce magnetism in CeCo4B.
