Organic- and molecule-based magnets

Abstract

Magnets have been known for millennia and are strongly associated with metals (e.g. Fe, Co, Ni, Gd), intermetallics (e.g. Co 17 Sm 2 , Nd 2 Fe 14 B), or their oxides (e.g. CrO 2 , Fe 3 O 4 ). The development of new magnetic materials has led to ubiquitous uses for electricity generation, memory storage media, and devices such as electric motors, microphones, telephones and computers. These magnets are fabricated via energy demanding metallurgical methods and are frequently brittle, chemically reactive, and possess elements in limited supply. The end of the last millennium has seen a surge in using organic, molecular, and polymeric materials as substitutes for metal and ceramic materials in many applications. Also, in the past few decades organic and molecule-based materials have been shown to magnetically order with examples having ordering temperatures exceeding room temperature, higher-than-iron saturation magnetizations, large coercive fields, etc. An overview of organic-based, and more generally molecule-based magnetic materials that exhibit unusual magnetic properties ranging from ferromagnets to synthetic antiferromagnets with emphasis on magnetic ordering using examples possessing organic nitriles ( CN) or inorganic cyanide (CN − ) is described.