Integrated HAMR Head Optical Transducer and Write Pole
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Solution Overview
Problem
As areal densities increase in magnetic recording, superparamagnetic instabilities arise due to reduced grain volume, making it difficult to maintain thermal stability, and existing recording heads struggle to provide sufficient magnetic writing fields, especially with materials having high magnetic crystalline anisotropy energy density.
Innovation Solution
The integration of an optical transducer within a magnetic recording device to heat the recording medium locally, combined with a write pole and return pole configuration that minimizes interference between the magnetic and optical fields, allowing for efficient delivery of magnetic fields and heat to the medium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If grain volume is reduced to increase areal density, then storage capacity increases, but thermal stability deteriorates due to superparamagnetic effects
Solution Approach 1:
The patent applies parameter changes by dynamically altering the temperature parameter of the recording medium. During writing, the medium is heated to reduce coercivity and enable recording on high-anisotropy materials with small grain volumes. During reading and storage, the medium returns to ambient temperature where high coercivity provides thermal stability. This temporal parameter change resolves the contradiction between small grain size (for high density) and thermal stability.
Solution Approach 2:
The patent implements periodic action through the cyclic heating and cooling of the recording medium. The medium undergoes periodic temperature cycles: heated during write operations to enable magnetization switching, then cooled for stable storage. This periodic thermal action allows the system to alternate between states of low coercivity (for writing) and high coercivity (for stable storage), resolving the density-stability contradiction.
2Reliability
If magnetic crystalline anisotropy energy density is increased to improve thermal stability, then thermal stability improves, but magnetic field strength from conventional heads becomes insufficient
Solution Approach 1:
The patent uses parameter changes by heating the recording medium to temporarily reduce its coercivity. This allows conventional magnetic heads to write on high-anisotropy materials that would otherwise require fields beyond their capability. The high anisotropy is maintained at ambient temperature for stability, while thermal energy temporarily lowers the energy barrier during writing.
Solution Approach 2:
The patent introduces thermal energy as an intermediary that facilitates the writing process. The heat acts as a mediator between the conventional magnetic head and the high-anisotropy medium, temporarily reducing the coercivity barrier to allow magnetization switching. This intermediary thermal action enables the use of high-Ku materials without requiring ultra-high field strength heads.
3Adaptability or versatility
If optical transducer is integrated with magnetic recording head, then HAMR functionality is achieved, but interference between magnetic and optical fields may occur
Solution Approach 1:
The patent applies segmentation by spatially separating the optical and magnetic functional elements within the integrated head. The optical transducer (laser source and waveguide) is positioned separately from the magnetic write pole and return pole. This segmentation allows independent optimization of optical and magnetic fields while minimizing their mutual interference, enabling HAMR functionality without compromising recording performance.
Solution Approach 2:
The patent uses the recording medium itself as an intermediary that separates the optical and magnetic fields. The optical field from the transducer heats the medium locally, while the magnetic field from the poles acts on the heated region. The medium acts as a mediator that receives both fields at different locations and times, allowing integration without direct field interference between the optical and magnetic components.
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 solution enables high areal density recording by maintaining thermal stability and enhancing magnetic field strength, overcoming superparamagnetic instabilities and the limitations of conventional recording heads.
Implementation Method 1
employing thermal energy to heat a local area on the recording medium before or at about the time of applying the magnetic write field to the medium
Implementation Method 2
A coil having a plurality of turns is located adjacent to the main write pole for inducing a magnetic field between the pole and a soft underlayer of the storage media
Implementation Method 3
The flux density that diverges from the tip into the soft underlayer returns through the return flux pole
Data Source
AI summary
A magnetic recording apparatus includes a write element and an optical device for heating a portion of a magnetic medium. The optical device and the write element are arranged to generally prevent the write element from affecting the optical fields generated by the optical device.