Tapered HAMR Writer Head Elements for High-Density Writing
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Solution Overview
Problem
Existing magnetic writer heads in hard disk drives face challenges in maintaining high areal density capacity (ADC) due to degraded magnetic performance when scaling down write head structures, especially with smaller media grains requiring larger coercive fields.
Innovation Solution
A HAMR writer head design incorporating a triangular layer with a tapered edge, a waveguide layer, a near field transducer layer, and a magnetic main pole with tapered sections, along with a heat sink layer, to enhance thermal and magnetic gradients for efficient data storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the write head structures are scaled down to match smaller media grains, then the areal density capacity increases, but the magnetic performance degrades
Solution Approach 1:
The patent applies parameter changes by introducing a tapered geometry to the main pole and optical layers, transforming the traditional rectangular structure into a tapered configuration. This geometric parameter change enables the scaled-down write head to generate sufficient magnetic field strength while maintaining compatibility with smaller media grains, thus improving areal density capacity without sacrificing magnetic performance
Solution Approach 2:
The patent employs composite materials in the HAMR writer head structure, combining magnetic materials with specific saturation magnetization (≥24 kG) with optical materials including tapered sections. This composite structure integrates both magnetic writing functionality and optical heating capability, enabling the system to achieve high areal density capacity while maintaining reliable magnetic performance through material composition optimization
2Quantity of substance
If the dimensions of write head structures are reduced, then the data storage density increases, but the coercive field requirement cannot be met
Solution Approach 1:
The patent applies local quality by creating a tapered structure where the main pole and optical layers have varying cross-sectional dimensions along their length. The tapered geometry concentrates magnetic flux and optical energy at the air-bearing surface, generating locally enhanced magnetic field strength that meets the coercive field requirement for smaller media grains while maintaining reduced overall dimensions for high data storage density
Solution Approach 2:
The patent introduces a dimensional change by transitioning from a uniform cross-section structure to a tapered structure with varying dimensions along the longitudinal axis. This dimensional variation creates a gradient in magnetic field distribution and optical intensity, enabling the scaled-down write head to generate sufficient coercive field at the media interface while maintaining reduced dimensions for high storage density
3Quantity of substance
If the write head is scaled down for higher density, then the areal capacity improves, but the magnetic field strength decreases
Solution Approach 1:
The patent applies parameter changes by specifying that the magnetic main pole material must have a saturation magnetization of about 24 kG or greater. This material parameter change ensures that even in a scaled-down structure, the magnetic field strength is sufficient to write to smaller media grains, thereby improving areal capacity without sacrificing magnetic field strength
Solution Approach 2:
The tapered structure creates local concentration of magnetic flux at the air-bearing surface, generating enhanced magnetic field strength at the critical writing interface. This local field enhancement enables the scaled-down write head to achieve high areal capacity while maintaining adequate magnetic field strength for effective writing
4Quantity of substance
If the thermal gradients are increased for higher storage density, then the data storage density improves, but the temperature at the main magnetic pole increases
Solution Approach 1:
The tapered optical layers create a concentrated distribution of optical energy and thermal gradient at the air-bearing surface where the media is located. This localized thermal concentration achieves the necessary conditions for high data storage density while the heat sink layer directs excess heat away from the main magnetic pole, preventing excessive temperature rise at that component
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 achieves a 60% higher magnetic field and 40% lower magnetic field angle at the recording location, resulting in improved areal density capacity and reduced temperature at the main magnetic pole, enhancing data storage density and reliability.
Implementation Method 1
a small laser diode that can temporarily transfer heat to tiny grains on the media platter to reduce the switching field
Implementation Method 2
a magnetic writer element that applies magnetic flux to the heated media grains and writes information
Implementation Method 3
a heat sink layer positioned adjacent to the NFT layer
Data Source
AI summary
Writer head products for heat-assisted magnetic recording devices and methods of making the same are disclosed. The writer heads include multiple layers including a waveguide blocking layer, a waveguide layer, a near-field transducer layer, a heat sink layer, and a peg layer. Each of the layers may comprise a tapered angle near an air-bearing surface. The writer heads further include a main magnetic pole adjacent to the optical component including the same tapered angle near the air-bearing surface.