Ordered arrangements of selective-area grown MnAs clusters as components for planar magneto-electronic devices: Experiment and theory

颗粒状混合结构的性质，包括嵌入在基质材料或排列在表面上的纳米团簇，可以广泛调整。与单相材料相比，复合混合物中的自由度更大，从而产生调谐。然而，这种颗粒混合物的技术应用主要限于宏观器件，即簇之间的平均距离远小于特征器件尺寸，因为大多数生长方法仅产生簇的随机排列。最近的进展，在不同的衬底上的选择性区域的金属有机气相生长的MnAs集群允许一个精确地调整的位置，尺寸和形状的铁磁性MnAs纳米团簇，从而获得有序排列的几个纳米团簇，这可能作为新的平面磁电子器件的起点。在这里，我们要研究的磁性和磁输运特性的个别MnAs集群以及耦合集群的安排。在生长过程期间或之后，通过修改布置的簇之间的界面，可以以受控的方式调谐耦合的簇布置的性质。磁性和磁输运的结果将相关的从头计算和比较。在这些结果的基础上，将提出新的器件结构，并进行初步测试。

The properties of granular hybrid structures, consisting of nanoclusters embedded in a matrix material or arranged on surfaces can be widely tuned. The tuneability arises from the larger number of degrees of freedom in a composite hybrid compared to a single-phase material. However, the technological application of such granular hybrids has been mainly restricted to macroscopic devices, i.e. where the mean distance between clusters is much smaller than the characteristic device size, as most growth methods yield random arrangements of clusters only. Recent progress in selective-area metal-organic vapor phase growth of MnAs clusters on different substrates allows one to accurately tune the position, the size and the shape of ferromagnetic MnAs nanoclusters and, thus, to obtain ordered arrangements of a few nanoclusters which may serve as the starting point for novel planar magnetoelectronic devices. Here, we want to study the magnetic and the magneto-transport properties of individual MnAs clusters as well as of coupled cluster arrangements. The properties of the coupled cluster arrangements can be tuned in a controlled way during the growth process or afterwards by modifying the interface between clusters of the arrangement. Magnetic and magnetotransport results will be correlated and compared with ab initio calculations. On the basis of these results novel device structures will be proposed and preliminary tests will be performed.