【作者】 沈青松；

【导师】 姚凯伦；

【作者基本信息】 华中科技大学 ， 凝聚态物理， 2009， 硕士

【摘要】 本文我们用计算软件WIEN2k计算了两类非纯有机磁性材料的电子态密度和磁矩。通过计算得到的态密度,我们发现,其中有四个材料具有明显的半导体特性,有一个材料具有金属特性,这些材料都具有重要的应用价值。计算的第一类材料是含- ( tfadt )基团非纯金属有机磁性材料[Ni(cyclam)][Cu(tfadt)2]。根据计算得到的磁矩和态密度,我们得知材料的磁性主要由Ni原子和Cu原子d轨道电子提供。化合物的总磁矩为3.000 u B,这与实验上测得的总自旋为S=3/2保持一致。同时,Ni原子和Cu原子的磁矩符号一致,说明它们之间存在着铁磁相互作用。由S原子和N原子上磁矩的大小和符号,知道化合物中铁磁耦合作用沿着链Cu-S-C-N-Ni传递,且铁磁耦合作用是通过自旋退局域化机制产生。计算的第二类材料是:含叠氮基-(N3)不同配位基团的非纯有机磁性材料[Cu(benzoate)(N3)] n、[Cu(1-naphthoate)(N3)]n、[Cu(2-methyl-benzoate)(N3)]n和Co(N3)(4-acetylpridine)。通过第一性原理计算,发现前面三个材料是有机磁性半导体材料,第一个和第二个材料的自旋向上电子态密度与费米面相切,第三个材料的自旋向下电子态密度与费米面相切。化合物中的磁性主要由Cu原子d轨道电子提供。配体在传递化合物中铁磁耦合作用时,既有自旋退局域化机制的参与,也有自旋极化机制参与。材料中的铁磁耦合都有一条沿着链Cu-N1-Cu来传递。最后我计算的一个材料是Co(N3)(4-acetylpridine)2,与上面四个材料不同的是,它是一个有机金属材料,而且叠氮基末端两个氮原子上的磁矩并不相等,相差近一个数量级。我们认为这主要是由于叠氮基传递铁磁耦合的方式发生了变化,以及磁性中心由Cu离子变成了Co离子。更多还原

【Abstract】 Two kinds of non-organic magnetic material’s electronic structure and magnetic moments are calculated by the wien2k software in this article. Through the density of states calculated by the wien2k software, we find that there are four non-pure organic magnetic semiconductor materials and one organic metal material. and These materials have very important application value.First, We calculate non-pure organic magnetic material [Ni(cyclam)][Cu(tfadt)2], according to the result, we find that the magnetic moment of this material are mainly provided by the d electron of Ni atom and Cu atom. The total magnetic moment is 3.000 u B, this is agreement with the total spin S=3/2 tested by the experiment. At the same time, the magnetic moment symbol of Ni atom and Cu atom are identical, this means that there is ferromagnetic interaction between Ni atom and Cu atom, from the magnitude and the symbol of S atom and N atom, we can see that the ferromagnetic coupling of material passes through Cu-S-C-N-Ni chain, and also from spin delocalization.The second materials we calculated are [Cu(benzoate)(N3)] n、[Cu(1-naphthoate)(N3)]n、[Cu(2-methyl-benzoate)(N3)]n and Co(N3)(4-acetylpridine). which are organic magnetic materials. By the first principle study, the first three materials are semiconductor. and every material have one spin energy belt contacting with Fermi surface, the magnetic moment of these three non-pure organic magnets materials mainly provided by d electron of Cu atom. ferromagnetic coupling action in the material passed by ligand not only from spin delocalization but also from spin polarization, there is one route that through Cu-N1-Cu chain.The last material we calculated is Co(N3)(4-acetylpridine)2,and it is different from the other four materials. It is an organic metal, and furthermore, magnetic moments of the end N atom on azido is not equal,but have one magnitude difference. I think the reason for it is the manner of azido passes through ferromagnetic coupling has changed, and the paramagentic center has been changed from Cu ion to Co ion.更多还原