Effect of Mechanical Cycling on the Magnetic Properties of Permalloy Films Electroplated on Stretchable Substrates

This work describes the fabrication of electroplated permalloy films on screen-printed silver ink patterns on thermoplastic polyurethane, and the effect of mechanical cycling on their magnetic properties. It was observed that cycling causes cracks in the permalloy film, which in turn results in decrease of the initial permeability of the material. This change was observed while the magnetic saturation, coercivity, and remanence remained relatively unchanged. However, permeability values saturate at about 90% of their original values between 1 and 5 cycles. This allowed for the potential use of these materials in stretchable magnetic devices such as stretchable inductors.