Würzburg ToCoTronics Colloquium

Within the landscape of novel computing schemes, magnon-based wave computing is a promising candidate. Magnons are the fundamental excitations of magnetic materials and can be transported without moving charges. Therefore, using magnons not only bears the promise of reduced power demands, but also enables novel paths to implement logic functionality due to the wave nature of magnons. Thinking about such devices, one necessary step is to demonstrate that building magnonic networks is possible. To that end, the magnonic analogs to common semiconductor devices, e.g., amplifiers, diodes and switches, need to be connected to each other – and in more complicated structures this will involve non-planar interconnects. To ensure long distance wave propagation with low losses, choosing a proper material system is crucial. Magnetic garnets are one of the prime candidate systems due to their excellent magnetic properties such as long spin diffusion lengths, narrow resonance linewidths and excellent tunability. However, to obtain these magnetic properties, thin films with high crystalline quality are necessary.

In this talk I will present two routes for the fabrication of non-planar yttrium iron garnet (YIG) structures. In the first route, a supercycle approach is used for the fabrication of YIG via atomic layer deposition. There, I will demonstrate the feasibility of the fabrication of high quality YIG with a conformal chemical deposition process, I will discuss the advantages and disadvantages of this technique and compare the quality of the so grown thin films with films grown by other techniques. The second route is based on the lateral solid phase epitaxy (LSPE) of YIG on top of a ceramic layer. There, I will present the basic dynamics of LSPE of YIG including the activation energy and the crystallization rates depending on different seed layers. Again, I will compare the thin films from this approach with other techniques and discuss its benefits and limitations.