Magnetic Head Protective Layer Design for Touch-Down Damage
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Solution Overview
Problem
The magnetic heads in HDDs are prone to damage during the touch-down process due to contact with the magnetic disk, which can affect the recording and reading performance and reliability, especially as recording density increases and the magnetic recording and reading element units are downsized.
Innovation Solution
A magnetic head with a protective layer that adjusts its thickness to reduce damage from contact with the magnetic recording medium, where the protective layer's regions are either flush or recessed to minimize contact damage and maintain performance and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the magnetic recording and reading element unit is brought into contact with the magnetic disk during touch-down operation to maintain flying height, then the flying height can be kept constant, but the magnetic recording and reading element unit may be damaged
Solution Approach 1:
A protective layer is formed on the magnetic recording and reading element unit before the touch-down operation. This protective layer acts as a cushion that absorbs the impact when the element unit contacts the magnetic disk during touch-down, preventing damage to the element unit while still allowing the flying height to be maintained through thermal expansion
2Productivity
If the magnetic recording and reading element unit is downsized to increase recording density, then recording density increases, but contact damage affects performance and reliability more significantly
Solution Approach 1:
The protective layer is formed on the downsized magnetic recording and reading element unit to provide impact absorption. This is particularly important for downsized elements where even minor contact damage can significantly affect performance and reliability, while the protective layer ensures that the element survives the touch-down operation without degradation
3Reliability
If a protective layer is formed on the magnetic recording and reading element unit to prevent contact damage, then reliability improves, but the gap between the magnetic head and magnetic disk may be affected
Solution Approach 1:
The protective layer is designed with specific local characteristics: it has a thickness of 0.0 to 2.0 nm on the air bearing surface side and extends to the magnetic recording and reading element unit. The layer is formed only in specific regions where protection is needed, and its thickness is carefully controlled to be thin enough not to significantly affect the gap between the magnetic head and disk, while still providing adequate protection against contact damage
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 adjusted protective layer reduces the impact of contact damage on the magnetic head's performance and reliability, ensuring consistent operation and recording density by minimizing contact between the magnetic recording and reading element protrusions and the magnetic disk.
Implementation Method 1
A protective layer that protects the element unit... reduces the impact of contact damage on the magnetic head's performance and reliability
Data Source
AI summary
According to one embodiment, a magnetic head includes a protective layer. When an element unit is a magnetic recording element unit, the protective layer includes a first region on a magnetic recording element protrusion and a second region on a magnetic recording element shield, the first region and the second region being flush with each other, or the first region being recessed more than the second region. When the element unit is a magnetic reading element unit, the protective layer includes a third region on a magnetic reading element protrusion and a fourth region on a magnetic reading element shield, the third region and the fourth region being flush with each other, or the third region being recessed more than the fourth region.