Magnetism of size selected, deposited transition metal and alloy clusters

当团簇与表面接触时，可能会经历关于其固有性质的强烈修改。电子结构弛豫可以特别地改变过渡金属团簇中的磁矩，因为它们与开放的3D壳层的电子构型直接相关。此外，与衬底的相互作用可能导致有效的磁团簇相互作用，从而产生超铁磁性。这里提出的实验涉及到质量选择的磁团簇和固体表面之间相互作用的这两个具体方面。利用x射线磁性圆二色谱的高灵敏度来研究原位沉积的团簇的磁性。我们将研究二元合金(FePT，CoPT)团簇的磁矩随原子组成的变化，这种原子组成可以通过小团簇尺寸的质量选择来精确地选择。同样，还将具体研究合金化对表面相互作用磁敏性的影响。我们将研究FeN/Cu(111)体系的有效磁团簇相互作用，以阐明这类体系的高临界温度和强磁各向异性背后的机制。在这里，我们将分别探讨颗粒大小和制备方法(稀有气体层中团簇沉积与团簇形成)的依赖关系。

Clusters may experience strong modifications with respect to their intrinsic properties when being in contact with a surface. Electronic structure relaxation may particularly modify the magnetic moments in transition metal clusters, since they are directly connected with the electronic configuration of the open 3d shell. In addition, the interaction with the substrate may lead to an effective magnetic cluster cluster interaction, giving rise to super-ferromagnetism. The experiment proposed here are concerned with these two specific aspects of interactions between mass selected magnetic clusters and solid surfaces. The high sensitivity of x-ray magnetic circular dichroism will be exploited to study the magnetic properties clusters deposited in situ. The evolution of the magnetic moments in binary alloy (FePt,CoPt) clusters will be studied as a function of atomic composition, which can be precisely chosen by mass selection at small cluster sizes. Likewise, the effect of alloying on the magnetic sensitivity to surface interaction will be specifically studied. Effective magnetic cluster cluster interactions will be studied for the system Fen/Cu(111) to elucidate the mechanism behind the high critical temperatures and strong magnetic anisotropies reported for this class of systems. Here, we will explore both, the dependence on particle size and the preparation method (cluster deposition versus cluster formation in rare gas layers), respectively.