Thermally Assisted Magnetic Head Slider with Localized Coating
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Solution Overview
Problem
Conventional thermally assisted magnetic head sliders face issues where the diamond-like carbon (DLC) coat layer used to protect the read and write portions degrades under high temperatures, leading to increased magnetic spacing and degraded reading performance.
Innovation Solution
A thermally assisted magnetic head slider design featuring a substrate with a light source module, a read portion, and a write portion, where a thinner first coat layer with a higher light absorption index is applied to the read portion and a thicker second coat layer with a lower light absorption index is applied to the write portion, along with a protective layer, to maintain performance under high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a thicker coat layer with lower light absorption index is used to protect the write portion from high temperature, then the thermal resistance is improved, but the magnetic spacing increases which degrades reading performance
Solution Approach 1:
The patent applies different coat layer thicknesses to different regions: the write portion has a thicker coat layer (5-20 nm) for thermal protection, while the read portion has a thinner coat layer (1-5 nm) to maintain magnetic spacing and reading performance. This local differentiation resolves the contradiction by optimizing each region according to its specific functional requirements.
2Measurement precision
If a diamond-like carbon (DLC) coat layer is used to protect both read and write portions, then the magnetic spacing is controlled, but the coating degrades under high temperature during writing operation
Solution Approach 1:
The patent uses different coat layer materials with different thermal stability characteristics in different regions. The write portion uses a thicker coat layer with lower light absorption index that is more resistant to thermal degradation, while the read portion uses a thinner DLC layer that provides good magnetic spacing control but is more sensitive to heat. This resolves the contradiction by matching material properties to functional requirements.
3Strength
If the coat layer thickness is increased to prevent damage in the write portion, then the thermal protection is improved, but the magnetic spacing between the magnetic recording medium and read portion increases
Solution Approach 1:
The patent implements non-uniform coat layer thickness across the head slider: the write portion has a thicker coat layer (5-20 nm) for enhanced thermal protection and structural integrity, while the read portion has a thinner coat layer (1-5 nm) to maintain minimal magnetic spacing. This spatial variation in thickness allows simultaneous optimization of protection and reading performance.
Data Source
AI summary
A thermally assisted magnetic head slider includes an air bearing surface facing to a magnetic recording medium, a read portion, and a write portion including a write element, a waveguide for guiding light generated by the light source module, and a plasmon unit provided around the write portion and the waveguide. A first coat layer with a first thickness which has a first light absorption index is covered on an opposed-to-medium surface of the read portion, and a second coat layer with a second thickness which has a second light absorption index is covered on an opposed-to medium surface of the write portion, wherein the second thickness is larger than the first thickness, and the second light absorption index is smaller than the first light absorption index. The slider can protect the write portion and improve the reading performance of the read portion.