Spatial effects in the DC modulation noise of advanced MP tape

Summary form only given. Experimental studies of DC modulation noise, as a function of the remanent magnetized state, for advanced MP tapes, when cycled through DC-demagnetization (DCD), indicate that their characteristics change as the thickness of the magnetic coating is reduced. Figure 1 shows a DCD noise spectral map for a 300 nm MP tape with a minimum in the demagnetised state, which is characteristic of thick media. Figure 2 shows a similar plot for a 150 nm tape with identical morphology. This is more characteristic of thin film noise. In order to understand these changing characteristics, we have modelled the experimental process.