Magnetic properties of copper hexadecaphthalocyanine (F16CuPc) thin films and powders
Magnetic properties of copper hexadecaphthalocyanine (F16CuPc) thin films and powders
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DOI：
10.1063/1.4773456
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发表时间：
2013-01
影响因子：
3.2
通讯作者：
Wei Wu;L. Rochford;S. Felton;Zhenli Wu;J. Yang;S. Heutz;G. Aeppli;T. Jones;N. Harrison;A. Fisher
中科院分区：
文献类型：
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作者：
Wei Wu;L. Rochford;S. Felton;Zhenli Wu;J. Yang;S. Heutz;G. Aeppli;T. Jones;N. Harrison;A. Fisher
报道了F16 CuPc薄膜和粉末的结构和磁性，包括X射线衍射（XRD）、超导量子干涉仪（SQUID）磁强计和交换相互作用的理论模型。对沉积在Kapton和二萘嵌苯-3，4，9，10-四羧酸-3，4，9，10-二酐（PTCDA）中间层上的厚度在100和160 nm之间的膜的XRD分析表明，膜的堆叠角（在文中定义）与厚度无关，但是织构被膜厚度和基底化学改性。SQUID测量表明，所有的样品是顺磁性的，结果证实了我们的理论模型，包括一维分子链的密度泛函理论计算和绿色的功能微扰理论计算的分子二聚体。通过理论研究一系列不同的几何构型，我们预测F16 CuPc分子之间的最大可能的交换相互作用是未氟化的铜酞菁（CuPc）的两倍。这种差异源于F16 CuPc中较小的分子间间距。我们对孤立的F16 CuPc分子的密度泛函理论计算还表明，与CuPc相比，F16 CuPc中的Kohn-Sham轨道的能级刚性移动了0.1eV，而没有对分子内自旋物理进行显着修改，因此这两种分子为独立变化的磁性和电荷输运提供了合适的平台。
The structural and magnetic properties of F16CuPc thin films and powder, including x-ray diffraction (XRD), superconducting quantum interference device (SQUID) magnetometry, and theoretical modelling of exchange interactions are reported. Analysis of XRD from films, with thickness ranging between 100 and 160 nm, deposited onto Kapton and a perylene-3,4,9,10-tetracarboxylic-3,4,9,10-dianhydride (PTCDA) interlayer shows that the stacking angle (defined in the text) of the film is independent of the thickness, but that the texture is modified by both film thickness and substrate chemistry. The SQUID measurements suggest that all samples are paramagnetic, a result that is confirmed by our theoretical modelling including density functional theory calculations of one-dimensional molecular chains and Green's function perturbation theory calculations for a molecular dimer. By investigating theoretically a range of different geometries, we predict that the maximum possible exchange interaction between F16CuPc molecules is twice as large as that in unfluorinated copper-phthalocyanine (CuPc). This difference arises from the smaller intermolecular spacing in F16CuPc. Our density functional theory calculation for isolated F16CuPc molecule also shows that the energy levels of Kohn-Sham orbitals are rigidly shifted ∼1 eV lower in F16CuPc compared to CuPc without a significant modification of the intra-molecular spin physics, and that therefore the two molecules provide a suitable platform for independently varying magnetism and charge transport.