Readback Responses in Three Dimensions for Multilayered Recording Media Configurations

Analytical read back signal modeling in magnetic recording

“…By switching x-and z-components in the coordinate system definitions (9)-(11) can be rewritten. The shielded tunnel magneto resistance (TMR) head is mainly sensitive to the z-component of the magnetic field (Wood and Wilton 2008). Hence, only the z-component is considered here.…”

“…A large number of analytical models for the magnetic read back signal have been developed in the past for longitudinal and perpendicular magnetic recording (Valcu and Bertram 2002;Roscamp et al 2002;Smith 1993;Wood and Wilton 2008;Shute et al 2006;Chai et al 2006;Suzuki et al 2006;Wilton et al 2004;Mallinson and Bertram 1984;Radhakrishnan et al 2007;Bertram 1994;Khizroev and Litvinov 2004;Richter 1999;Bertram 1994, 1996;Nishida 2001, 2003). Initially, the ''on-track'' response was approximated in 2-D by neglecting off-track effects and approximating an isolated bit transition which yields a bell-shaped curve for longitudinal recording and a di-bit curve for perpendicular recording (Richter 1999).…”

“…Initially, the ''on-track'' response was approximated in 2-D by neglecting off-track effects and approximating an isolated bit transition which yields a bell-shaped curve for longitudinal recording and a di-bit curve for perpendicular recording (Richter 1999). With increasing storage density and decreasing bit aspect ratio there was a need to switch from initial 2-D models to 3-D models (Wood and Wilton 2008). Many of the models developed consider isolated magnetic bit transitions (Valcu and Bertram 2002;Wood and Wilton 2008;Chai et al 2006).…”

“…With increasing storage density and decreasing bit aspect ratio there was a need to switch from initial 2-D models to 3-D models (Wood and Wilton 2008). Many of the models developed consider isolated magnetic bit transitions (Valcu and Bertram 2002;Wood and Wilton 2008;Chai et al 2006). A commonly used technique is based on the principle of reciprocity as applied in (Roscamp et al 2002;Smith 1993;Chai et al 2006;Yuan and Bertram 1994;Yuan and Bertram 1996) or Fourier components (Shute et al 2006;Suzuki et al 2006;Nishida 2001, 2003).…”

“…Furthermore, servo designs in BPM that incorporate either only ''up'' or only ''down'' magnetized bits could be captured by the model. Track edge effects and written transitions that are sometimes modeled by an ellipse (Wood and Wilton 2008) would be decreased as the bits on patterned media would potentially have a well defined shape. More complicated shapes could be investigated by using the model developed and a so-called micro grid approach (Chai et al 2006) that is very accurate and considerably faster than finite element solutions.…”