antiferromagnetic
Concise Oxford English Dictionary © 2008 Oxford University Press:
antiferromagnetic/antɪfɛrəʊmaɡˈnɛtɪk/
▶adjective Physics denoting or exhibiting a weak form of magnetism in which there is an antiparallel alignment of adjacent electron spins in a crystal lattice.
'antiferromagnetic' also found in these Oxford entries:

