Magnetic Recording Head Pole Tip Bulge for Areal Density
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Solution Overview
Problem
Current disk drive technologies face limitations in achieving high areal density due to the constraints of magnetic write fields and fly height control, which affect the precision and efficiency of data storage.
Innovation Solution
The design of a perpendicular magnetic recording head with a main pole tip having a controlled bulge shape, including specific angles and widths, enhances the magnetic write field and field gradient, allowing for improved areal density and reduced domain lock-up issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a smaller and more tightly controlled magnetic writing field is used, then areal density increases, but fly height control precision and stability deteriorate
Solution Approach 1:
The patent applies local quality by creating a bulge region at the pole tip with different geometric properties than the rest of the pole structure. This localized geometric modification concentrates the magnetic field at the specific location where writing occurs, enabling tighter field control for higher areal density without compromising overall fly height stability. The bulge region serves as a focal point for field concentration while the broader pole structure maintains structural integrity and fly height control.
Solution Approach 2:
The patent employs parameter changes by modifying the geometric parameters of the pole tip - specifically creating a bulge with defined radius (50-200 nm) and height (25-100 nm). These parameter changes transform the pole tip geometry to optimize magnetic field distribution. The controlled alteration of these geometric parameters enables the magnetic field to be more tightly confined at the writing interface, increasing areal density while the overall pole structure maintains adequate fly height control.
2Quantity of substance
If the pole tip geometry is modified to enhance write field, then areal density improves, but manufacturing complexity increases
Solution Approach 1:
The patent applies spheroidality by introducing a curved bulge region at the pole tip instead of a flat or sharp geometry. The bulge is characterized by a radius of curvature (50-200 nm) that creates a smooth, rounded profile. This curved geometry naturally concentrates magnetic field lines at the apex of the bulge, enhancing write field strength and confinement. The spherical/curved shape is more effective at field concentration than angular geometries while potentially being more manufacturable through controlled deposition or etching processes that can create rounded features.
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 enables increased data storage capacity by optimizing the write field and field gradient, improving off-track erasure and domain lock-up, thereby enhancing recording areal density and stability.
Implementation Method 1
An air bearing forms between the head and the disk due to the disk rotating at high speeds to provide controlled head to disk spacing
Implementation Method 2
Magnetic fields emanating from the write transducer pole tip switches magnetization of the magnetic medium, i.e., writing to the medium
Data Source
AI summary
A perpendicular magnetic recording head for use in a hard disk drive has a main pole that has a main pole tip in proximity to an air bearing surface. The main pole tip has a first width at the ABS, extending distally at a first angle measured from the plane of the ABS to a second width measured at a first distance from the ABS. The main pole tip extends distally at a second angle measured from the plane of the ABS from the second width to a third width, wherein the second angle is less than the first angle. The main pole tip extends distally at a third angle measured from the plane of the ABS from the third width to a fourth width, wherein the third angle is greater than the second angle. The first distance is between 25 and 100 nanometers.