In some examples, a method comprising depositing a functional layer (e.g., a magnetic layer) over a substrate; depositing a granular layer over the functional layer, the granular layer including a first material defining a plurality of grains separated by a second material defining grain boundaries of the plurality of grains; removing the second material from the granular layer such that the plurality of grains of the granular layer define a hard mask layer on the functional layer; and removing portions of the functional layer not masked by the hard mask layer, wherein the depositing of the functional layer, the depositing of the granular layer, removing the second material, and removing the portions of the functional layer are performed in a vacuum environment.