Perpendicular Magnetic Recording Head With Overhanging Trailing Side Layer
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Solution Overview
Problem
Current magnetic recording devices face challenges in achieving high in-plane recording density due to the reduction in size of magnetic fine-particles, leading to destabilization from thermal fluctuation of magnetization and difficulties in generating adequate perpendicular magnetic fields, especially with skew angles affecting adjacent track data.
Innovation Solution
A magnetic recording head design featuring a main pole with a throat height portion and a flare portion that gradually increases in width, along with magnetic shields and a roof magnetic layer overhanging on the trailing side to enhance magnetic field strength and clearance angle, thereby maintaining writing performance even with reduced pole width.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the width of the main pole is reduced to increase surface recording density, then the recording density is improved, but the magnetic field strength becomes insufficient for reversal of magnetization
Solution Approach 1:
The patent introduces a vertical dimension by adding a magnetic layer that overhangs the trailing side of the main pole in the element height direction. This three-dimensional structure allows the magnetic field to be generated not only from the horizontal width of the pole but also from the vertical extension, effectively increasing the magnetic field strength without increasing the horizontal footprint, thus maintaining high recording density while solving the magnetic field strength insufficiency.
Solution Approach 2:
The magnetic field generation function is segmented between the main pole and the overhanging magnetic layer. The main pole provides the primary magnetic field, while the overhanging magnetic layer contributes additional magnetic flux from its trailing side, creating a composite magnetic field structure that achieves sufficient field strength with a reduced pole width.
2Reliability
If the bevel angle of the main pole is increased to secure magnetic clearance angle, then the magnetic clearance angle is improved, but the magnetic field strength is reduced due to reduced emitting area
Solution Approach 1:
The overhanging magnetic layer extends in the element height direction, adding a vertical component to the magnetic field generation. This allows the magnetic clearance angle to be maintained through the bevel angle of the main pole while the vertical extension compensates for the reduced horizontal emitting area, preserving magnetic field strength.
Solution Approach 2:
The magnetic layer is strategically positioned to overhang specifically on the trailing side of the main pole, creating a localized enhancement of magnetic flux in the region where it is most needed for maintaining field strength, while the bevel angle structure maintains the magnetic clearance angle for preventing adjacent track interference.
3Quantity of substance
If the width of magnetic fine-particles is reduced to increase recording capacity, then the recording capacity is improved, but thermal fluctuation of magnetization destabilizes the magnetization area
Solution Approach 1:
The perpendicular magnetic recording method is employed as a preliminary approach to stabilize magnetization before data recording. By recording magnetization signals in a direction perpendicular to the recording medium and increasing the thickness of the recording layer, the volume of magnetic fine-particles is effectively increased, which stabilizes magnetization against thermal fluctuations while still allowing high recording capacity through reduced particle width.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design secures adequate magnetic field strength and a larger magnetic clearance angle, enabling high recording density while preventing data attenuation on adjacent tracks, even with skew angles, by increasing the difference in magnetic field strength between the trailing and leading sides of the main pole.
Implementation Method 1
a magnetic film formed on a throat height portion near the rear in the element height direction with respect to an ABS and formed on the flare portion which overhangs in a track width direction on the trailing side of the main pole
Implementation Method 2
magnetic shields disposed via a nonmagnetic layer on a trailing side of the main pole and on both sides in a track width direction of the main pole
Data Source
AI summary
A recording head having a narrowed track has a high recording magnetic field strength and a high recording magnetic field gradient has certain problems which may be difficult to overcome. In one embodiment, a magnetic film, which overhangs from a track width, is provided on a trailing side of a. region retracted from an ABS of a main pole facing a recording medium. Thereby, a magnetic field strength on the trailing side is increased so that a difference in distribution of magnetic field strength defined by a geometrical bevel angle given to the main pole is increased. Consequently, writing performance of the main pole is improved while forming a large magnetic clearance angle with respect to an adjacent track and suppresses writing into an adjacent track when skew occurs. Other systems and methods are also disclosed regarding a head with a high recording magnetic field using an overhanging magnetic film.