Perpendicular Magnetic Recording Write Head Pole Transition
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Perpendicular magnetic recording (PMR) systems face challenges in increasing areal density due to limitations in write pole tip geometry at the air bearing surface while maintaining sufficient magnetic fields.
Innovation Solution
The design of a perpendicular magnetic recording write head with a main pole that transitions from a non-rectangular shape at the air bearing surface to a rectangular shape within a specific distance (10 nm to 100 nm) away from the surface, incorporating leading and trailing beveled surfaces to enhance magnetic field distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the write pole tip geometry is reduced in size at the air bearing surface to increase areal density, then the storage capacity increases, but the magnetic field strength becomes insufficient
Solution Approach 1:
The main pole is designed with non-uniform cross-sectional geometry along its length: a smaller non-rectangular cross-section at the air bearing surface for high areal density, transitioning to a larger rectangular cross-section at the rear for sufficient magnetic field generation. This local variation in geometry allows simultaneous optimization of both areal density and magnetic field strength.
Solution Approach 2:
The pole transition utilizes the vertical dimension (distance from air bearing surface) to resolve the contradiction. By varying the pole cross-section along the vertical axis rather than maintaining a uniform horizontal geometry, the design achieves both small pole tip area for high density and sufficient pole volume for magnetic field strength.
2Quantity of substance
If the main pole maintains a small cross-section at the air bearing surface to achieve high areal density, then storage capacity increases, but domain lockup occurs
Solution Approach 1:
The pole geometry is optimized locally at different positions: the small non-rectangular cross-section at the air bearing surface enables high areal density, while the larger rectangular cross-section at the rear prevents domain lockup by providing sufficient magnetic flux capacity.
Solution Approach 2:
The transition in pole geometry along the vertical dimension resolves the domain lockup issue. The increased pole cross-sectional area at the rear (away from the air bearing surface) provides enough magnetic flux to prevent domain lockup while maintaining the small pole tip area needed for high areal density.
3Ease of manufacture
If the main pole has a rectangular shape at the air bearing surface for simplicity, then manufacturing is easier, but magnetic field distribution and signal-to-noise ratio deteriorate
Solution Approach 1:
The pole geometry is optimized for its specific function at each location: the non-rectangular cross-section at the air bearing surface (where precision matters most for signal-to-noise ratio) provides superior magnetic field distribution, while the rectangular cross-section at the rear simplifies manufacturing.
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
This configuration improves out-of-plane magnetic field strength, reverse overwrite gain, signal-to-noise ratio, and cross-track magnetic anisotropy, enabling higher recording areal density and mitigating domain lockup.
Implementation Method 1
The magnetic head writes data to the disk by magnetizing segments along the circular tracks of the rotating disk
Implementation Method 2
the magnetic flux, which results from the magnetic field produced by the magnetic head, is collected by the soft magnetic under-layer and returned to the magnetic head to complete the magnetic circuit
Data Source
AI summary
A main pole of a perpendicular magnetic recording write head is disclosed with a non-rectangular shape at the air bearing surface and a rectangular shape behind the air bearing surface. The main pole transitions from the non-rectangular shape to a rectangular shape at a distance of 10 nm to 100 nm behind the air bearing surface. The main pole includes leading and trailing beveled surfaces that extend from the non-rectangular shape of the pole at the air bearing surface toward the rectangular shape transition.