Organic-inorganic hybrid spintronics

近年来，自旋电子学与有机材料的结合形成了有机自旋电子学这一新领域。随着分子磁电阻或有机磁电阻等效应的发现，以及有机自旋阀或自旋忆阻器等器件的发现，该领域的主要焦点是通过分子上电极的作用，在由金属或铁磁引线与有机分子接触组成的器件中诱导功能。这种作用包括诱导分子中的自旋极化、将分子磁矩钉扎到衬底的磁矩或通过与衬底的电子气的相互作用来修改分子状态和轨道的效应。只是最近，我们证明，相反的行动也可以显着的大小在揭示一个交换偏置薄Co膜的反铁磁有序分子膜的行动。在这个项目中，我们打算扩大我们的研究的分子上的铁磁电极的行动，以实现多功能的设备，其中分子的结构转变开关的电极的磁性。将讨论两个主要观点。首先，可以通过外部刺激如电场、光或温度在磁性和非磁性状态之间切换的自旋交叉复合物将交换耦合到薄铁磁层。通过改变分子的构象，从而改变它们的自旋状态，我们预计磁性基底中的磁矩、磁各向异性和磁滞会发生很大的变化。由于分子的两个自旋状态之间的大尺寸变化，我们预计这种效应会被磁弹性耦合增强。第二，使用铁电分子膜，在铁磁体的界面处的高电场可以引起金属的磁性的变化，实现多铁性混合系统。该系统将与广泛的实验技术进行研究，范围从局部探针，如扫描隧道显微镜，原子和磁力显微镜空间平均技术，如X射线圆磁二色性，磁光克尔效应和运输测量。通过结合两位主要研究人员及其团队的专业知识，可以利用这种广泛的技术来确定这些混合系统中的相关物理相互作用。

The combination of spintronics and organic materials has recently led to the formation of the new field of organic spintronics. With the discoveries of effects like molecular magnetoresistance or organic magnetoresistance and devices like organic spin valves or spin-memristors, the main focus of the field was to induce a function in a device consisting of metallic or ferromagnetic leads in contact with organic molecules by the action of the electrodes on the molecules. This action includes effects inducing a spin-polarization in the molecules, pinning molecular magnetic moments to that of the substrate or modifying the molecular states and orbitals by the interaction with the electron gas of the substrates. Only recently, we demonstrated that also the opposite action can be of significantly size in revealing an exchange bias of thin Co films by the action of an antiferromagnetically ordered molecular film. In this project, we intend to expand our studies of the action of molecules on the ferromagnetic electrodes in order to realize multifunctional devices, in which structural transitions in molecules switch the magnetic properties of the electrodes. Two main ideas will be addressed. First, spin-crossover complexes that can be switched between a magnetic and a non-magnetic state by external stimuli like electric fields, light or temperature will be exchange coupled to thin ferromagnetic layers. By switching the conformation of the molecules and thus their spin state, we expect large changes in the magnetic moment, magnetic anisotropy and hysteresis in the magnetic substrate. We expect such effects to be enhanced by magneto- elastic coupling, thanks to the large size change between the two spin states of the molecules. Second, using ferroelectric molecular films, the high electric field at the interface to the ferromagnet can induce changes in the magnetic properties of the metal realizing a multiferroic hybrid system. The systems will be studied with a broad range of experimental techniques ranging from local probes like scanning tunnelling microscopy, atomic and magnetic force microscopy to spatially averaging techniques like X-ray circular magnetic dichroism, magneto-optical Kerr effect and transport measurements. By combining the know-how of the two principle investigators and their groups, this wide spectrum of techniques can be utilized to pinpoint the relevant physical interactions in these hybrid systems.