The title system is a mixture of two well-studied antiferromagnets, which e
xhibit metamagnetic transitions near 31 kG (Co) and 19 kG (Ni), respectivel
y. It is found that in Co1-xNixCl2 . 2H(2)O the metamagnetism persists, and
that for compositions where the nickel species is a sufficiently large min
ority component the transition occurs at fields substantially less than for
either pure component. (C) 2001 Elsevier Science B.V. All rights reserved.