Domain formation and magnetization reversal characteristics in permalloy disks on aerogels

Patterning permalloy magnetic discs on flexible substrates, such as PDMS, has garnered recent attention for applications in a variety of sensing applications, and have been recently explored to impart controllable mechanical deformation. Here, we explore the effect that varying PDMS and aerogel substrates have on the magnetic structure and reversal behavior on arrays of permalloy discs using Kerr microscopy. Discs of varying pitch, width, and thickness discs were grown using sputter deposition in combination with a variety of shadow masks. The resulting patterns showed increased disorder relative to patterns grown on Si substrates, and accordingly higher coercive fields. We further observe key differences in domain formation at remanence, which we qualitatively link to deformation of the substrate during the growth process.