| With the recent release of perpendicular magnetic recording products, the drive for enhancement of current technology and development of future technologies for achieving recording densities of Terabit/In2 is of unprecedented importance. This thesis strives to address key factors (via micromagnetics) that would affect recording at such ultra-high densities. Magnetostatic fields emanating out of recorded patterns and DC erased regions (worst case scenario) in neighboring tracks are detrimental towards recording at increased track densities. A novel side-shield design is proposed and magnetically characterized in a restrictive situation to redirect the stray magnetic flux, thereby reducing this source of noise. Another factor, reduction of grain sizes is required to maintain a sufficient signal to noise ratio at Terabit/In 2 recording but introduces superparamagnetism. The related writability and thermal stability problems summarize a "trilemma" that curtails the improvement of magnetic recording densities. Accepting the material saturation magnetization constraints of the recording head as a physical limit, the media structure is altered to reduce the switching field requirements, thereby alleviating the trilemma. An exchange coupled composite (ECC) media structure, with ferromagnetically exchange coupled hard and soft regions, has been shown to be an impressive candidate for future recording technology. The response of ECC media to thermal fluctuations is extensively studied and estimates of the ECC media attempt frequency for Terabit/In2 recording are provided. An interesting dependence of the attempt frequency on structure and intragranular exchange coupling is discussed including the added advantages of thermal-fluctuation assisted recording. Appropriate writer designs are elaborated on, in an effort to compare with conventional perpendicular recording. |
