Perpendicular magnetic recording/reading apparatus
AssigneeKabushiki Kaisha Toshiba
InventorKoji Yano
Life of this patent
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Abstract
The maximum external magnetic field of a magnetic recording medium longitudinal component which is applied to a magnetic recording medium is smaller than an absolute value Hn of a magnetic field at the intersection of a straight line connecting two points of an M-H curve in the longitudinal direction of a soft magnetic backing layer and a tangent of the M-H curve. One of the two points is a point (Hs, Ms) at which magnetization saturates in the first quadrant. The other of the two points is a positive intersection (0, Mr) of the M-H curve and the ordinate. The tangent is at a negative intersection (−Hc, 0) of the M-H curve and the abscissa.
Claims12
A perpendicular magnetic recording/reading apparatus comprising a perpendicular magnetic recording medium including a nonmagnetic substrate, and a magnetization fixing layer for a backing layer, a soft magnetic backing layer, and a perpendicular magnetic recording layer formed in the order on said nonmagnetic substrate,
- wherein a maximum external magnetic field of a magnetic recording medium longitudinal component which is applied to said perpendicular magnetic recording medium is smaller than an absolute value Hn of a magnetic field at an intersection of a straight line connecting two points of an M-H curve in the longitudinal direction of said soft magnetic backing layer and a tangent of the M-H curve, one of the two points being a point (Hs, Ms) at which magnetization saturates in the first quadrant, the other of the two points being a positive intersection (0, Mr) of the M-H curve and the ordinate, and the tangent being at a negative intersection (−Hc, 0) of the M-H curve and the abscissa, and the maximum external magnetic field of the magnetic recording medium longitudinal component which is applied to the outermost perimeter of a recording area of said perpendicular magnetic recording medium is smaller than the Hn of said soft magnetic backing layer.
A perpendicular magnetic recording/reading apparatus comprising a perpendicular magnetic recording medium including a nonmagnetic substrate, and a magnetization fixing layer for a backing layer, a soft magnetic backing layer, and a perpendicular magnetic recording layer formed in the order on said nonmagnetic substrate,
- wherein a maximum external magnetic field of a magnetic recording medium longitudinal component which is applied to said perpendicular magnetic recording medium is smaller than an absolute value Hn of a magnetic field at an intersection of a straight line connecting two points of an M-H curve in the longitudinal direction of said soft magnetic backing layer and a tangent of the M-H curve, one of the two points being a point (Hs, Ms) at which magnetization saturates in the first quadrant, the other of the two points being a positive intersection (0, Mr) of the M-H curve and the ordinate, and the tangent being at a negative intersection (−Hc, 0) of the M-H curve and the abscissa, and a spacing between said perpendicular magnetic recording medium and said driving motor is not less than about 3 mm.
A perpendicular magnetic recording/reading apparatus comprising a perpendicular magnetic recording medium having a nonmagnetic substrate, and a magnetization fixing layer for a backing layer, soft magnetic backing layer, and perpendicular magnetic recording layer formed in the order named on said nonmagnetic substrate,
- wherein said perpendicular magnetic recording medium has a recording area in which magnetization directions in said magnetization fixing layer for a backing layer and said soft magnetic backing layer are the same direction owing to an exchange coupling interaction, and a non-recording area in which the magnetization directions are not the same direction, and the sum of a maximum external magnetic field of a magnetic recording medium longitudinal component which is applied to the outermost perimeter of said recording area, and a demagnetizing field of said soft magnetic backing layer in a portion of said perpendicular magnetic recording layer in which the magnetization directions in said magnetization fixing layer for a backing layer and said soft magnetic backing layer are not the same direction, is smaller than the Hn of said soft magnetic backing layer.
A perpendicular magnetic recording/reading apparatus comprising a perpendicular magnetic recording medium having a nonmagnetic substrate, and a magnetization fixing layer for a backing layer, soft magnetic backing layer, and perpendicular magnetic recording layer formed in the order named on said nonmagnetic substrate,
- wherein said perpendicular magnetic recording medium has a recording area in which magnetization directions in said magnetization fixing layer for a backing layer and said soft magnetic backing layer are the same direction owing to an exchange coupling interaction, and a non-recording area in which the magnetization directions are not the same direction, and letting Mr be the residual magnetization in said magnetic recording medium, t be the film thickness, Hc be the coercive force of said soft magnetic backing layer, Hex be the longitudinal component applied to the outermost perimeter of said recording area of said magnetic recording medium, and Hxm be the demagnetizing field of soft magnetic backing layer equations (a) to (b) below are met:
- Mr/πμ0·(2·tan −1(t/(2a)+1)−π)=(Hc+Hn)/2+Hex (a)
- Hxm=2·Mr/(πμ0)·tan−1((t/4)/(a(a+t/2))1/2) (b)
- Hxm+Hex<Hn (c).
A perpendicular magnetic recording/reading apparatus comprising a perpendicular magnetic recording medium having a nonmagnetic substrate, and a magnetization fixing layer for a backing layer, soft magnetic backing layer, and perpendicular magnetic recording layer formed in the order named on said nonmagnetic substrate,
- wherein said perpendicular magnetic recording medium has a recording area in which magnetization directions in said magnetization fixing layer for a backing layer and said soft magnetic backing layer are the same direction owing to an exchange coupling interaction, and a non-recording area in which the magnetization directions are not the same direction, and a spacing between said perpendicular magnetic recording medium and said driving motor is not less than about 3 mm.
Dependencies are inferred from the claim text.