The Role of Media Damping in a Perpendicular Recording System

• Published in: IEEE transactions on magnetics Vol. 44; no. 1; pp. 207 - 210
• Main Authors: Batra, S., Roscamp, T., Scholz, W.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: New York, NY IEEE 01.01.2008; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Coercive force; Cross-disciplinary physics: materials science; rheology; Damping; data rate; Demagnetization; dynamic coercivity; Dynamical systems; Dynamics; Exact sciences and technology; Footprints; Landau-Lifshitz-Gilbert equation; Magnetic heads; Magnetism; Magnetization; Materials science; Mathematical models; Media; Micromagnetics; Other topics in materials science; Perpendicular magnetic recording; Physics; Recording; relaxation mechanism; Studies; Thermal degradation; Thermal factors; Thermal stability; Damping; dynamic coercivity; Coercive force; data rate; Landau-Lifshitz-Gilbert equation; Mechanism; Magnetic recording; Magnetic properties; relaxation mechanism
• ISSN: 0018-9464; 1941-0069
• DOI: 10.1109/TMAG.2007.912825

This paper discusses the role of media damping for a perpendicular recording system that uses a realistic head field and media parameters in a micromagnetic model based on the Landau-Lifshitz-Gilbert formulation for the magnetization dynamics. The modeling approach uses pulsed write fields of varying pulse duration to record footprints of the head on the media. Using a criterion that 95% of the grains are reversed in the footprints, we calculate the field needed to record as a function of pulse duration, i.e., the dynamic coercivity. As shown in a previous paper, we find two distinct regions in the dynamic coercivity plots. The thermally dominated (long time) region can be described by appropriately including the demagnetization effects in the thermal stability factor K u V/k B T. The short time (dynamic) behavior shows a precipitous increase in the required recording field accompanied by an increase in the erase width. The latter effect causes the recording performance to degrade, especially in the short time dynamic regime. The onset of dynamic effects strongly depends on the media damping. In order to achieve high data and high areal density, we need to optimize damping in the recording heads and media.