Patent ID: 7095581
Filing Date: 2006-08-22
Classification: B82Y,G11B

Abstract:
1. A magnetic recording and reproducing apparatus comprising a magnetic recording medium having a data information recording portion and a servo information portion for tracking, and a magnetic head for detecting servo information of said servo information portion and recording and reproducing data information on and from said data information recording portion, wherein said servo information portion is composed of perpendicular magnetic recording layers formed by convex portions based on a predetermined convex-concave pattern, said servo information portion comprising a burst portion where burst signals for tracking are recorded, said burst portion is formed by disposing at predetermined positions the perpendicular magnetic recording layers in the form of the convex portions where the burst signals are recorded, said perpendicular magnetic recording layer in the form of the convex portion has a first and a second substantially trapezoidal shape in a track width direction (track radial direction) and in a track circumferential direction, respectively, and when an upper side corresponding to an upper surface of said perpendicular magnetic recording layer in the form of the convex portion is given as W an upper side corresponding to the upper surface of said perpendicular magnetic recording layer in the form of the convex portion is given as L a thickness of said perpendicular magnetic recording layer in the form of the convex portion is given as t (equal to a height from W a coercive force, a saturation magnetization, and a coercive force squareness ratio in a direction perpendicular to the film plane of said perpendicular magnetic recording layer in the form of the convex portion are given as Hc, Ms, and S*, respectively, a specification of said burst portion is set so that said coercive force squareness ratio S* takes a value of 0.8 or more and a relationship of a first inequality is satisfied, said first inequality given as