Molecular magnets: Hybrid organic–inorganic layered compounds with very long-range ferromagnetism

Abstract

The correlations between structures and magnetic properties of new hybrid layered compounds M 2(OH) 3X (M=Co or Cu), where X is an exchangeable organic anion, are investigated. When the anion is a simple spacer (aliphatic chain), ferromagnetic in-plane interactions dominate, and the situation depends to a large extent on the interlayer spacing d. For small spacings ( d<10 Å), 3D antiferromagnetic order is stabilized, while large spacings favor spontaneous magnetization, even for d≈40 Å, due to dipolar through-space interactions. When X is a radical anion, new metal-radical magnets, with d close to 20 Å, are achieved. Strong interactions between the 3d and π electrons are evidenced, and a net magnetic moment occurs at low temperature. Such compounds are promising for the design of new molecular multiproperty materials.