Ion-beam etching of groove patterns into garnet films

The technique of ion-beam milling is applied to the structuring of garnet layers. Rf-sputtered titanium is found to be an appropriate masking material as its sputter etch rate is small and almost independent from the angle of incidence of the ion beam. In contrast, the garnet has a prominent etch rate angular dependence. The optimal conditions for the generation of grooves in garnet layers, masked by rf-sputtered Ti, are reported. By applying this technique, a well-resolved mosaic pattern of 20 μm periodicity and 5.5 μm depth has been formed in an LPE iron garnet film of 5 μm thickness.