Readback Responses in Three Dimensions for Multilayered Recording Media Configurations

We have applied a technique for modeling the transmission of three-dimensional (3D) magnetic fields through an arbitrary number of layers of a layered structure to the specific case of a recording medium in order to study and explain the readback response for a variety of perpendicular recording configurations. We examine in particular the low-frequency response associated with flux-flow in the soft underlayer and the behavior of the main response for finite read and write widths. Our work leads to a useful analytic approximation for the 3D on-track readback response.