di·a·mag·net·ic 
(dī′ə-măg-nĕtĭk)
(dī′ə-măg-nĕtĭk)adj.
Of or relating to a substance that generates a magnetic field in the direction opposite to an externally applied magnetic field and is therefore repelled by it.
di′a·magne·tism (-nĭ-tĭz′əm) n.