Nonlinear timing shift in high frequency magnetic recording determined with time resolved Kerr microscopy

As we move to higher data rates and higher areal densities, nonlinear effects start to determine the data patterns written on a hard disk. In this context it is necessary to develop methods that can help to determine the origin of nonlinear effects, e.g., that can help to distinguish between nonlinear effects caused by areal density from transient effects caused by high data rates. In this article we concentrate on the latter and show data for nonlinear timing shift measured directly on the air bearing surface of recording heads by means of time resolved magneto-optical Kerr microscopy. We compare the data to a simple t/(t + τ) model for the head field rise time.