Development of Organic Ferromagnets Based on Transition Metal Phthalocyanines

合成了一系列碱金属掺杂过渡金属酞菁（MPcs）有机铁磁材料，并对其磁性能和晶体结构进行了研究。所有的MPc样品，其中M=Mn, Fe, Co, Ni，掺杂钠或钾，在室温下表现出铁磁行为。x射线衍射图和透射电镜图像表明，MPc分子在碱金属掺杂的MPc样品中形成三维随机网络。提出了连接的MPc分子中过渡金属离子之间通过离域π电子的三维铁磁相互作用来解释远高于室温的高居里温度。合成了高分子聚合物，并对其结构和磁性能进行了研究。在室温下的磁化测量中也观察到铁磁行为。这些实验结果可能是在有机材料中发现高居里温度铁磁性的线索。

A series of organic ferromagnetic materials based on transition metal phthalocyanines (MPcs) doped by alkaline metals are synthesized and the magnetic properties and the crystal structures are investigated. All the samples of MPc, where M=Mn, Fe, Co, Ni, doped by sodium or potassium, show ferromagnetic behavior at room temperature. X-ray diffraction patterns and transmission electron microscopy images suggest that the MPc molecules form three-dimensional random networks in the alkaline metal doped MPc samples. Three-dimensional ferromagnetic interactions between transition metal ions in connected MPc molecules via delocalized π-electrons are proposed to explain the high Curie temperature well above room temperature. We also synthesized the MPc polymers and studied its structure and magnetic properties. Ferromagnetic behavior is also observed in the magnetization measurements at room temperature. These experimental results could be a clue to finding high Curie temperature ferromagnetism in organic materials.