Near Field Transducer Anneal for HAMR Heads
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Solution Overview
Problem
The increasing demand for higher data density in magnetic data storage systems creates a conflict between the need for smaller write heads and higher magnetic coercivity and anisotropy of the media, as smaller write heads produce weaker magnetic fields, making it difficult to record and stabilize data bits effectively.
Innovation Solution
A magnetic write head with a thermally conductive, electrically insulating layer is used to anneal an optical near-field transducer antenna without damaging surrounding magnetic structures, allowing for effective heat-assisted magnetic recording by locally heating the media to reduce coercivity and ensure thermal stability of recorded bits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the write head size is reduced to increase data density, then the data storage capacity is improved, but the magnetic write field strength decreases making it difficult to record to high coercivity media
Solution Approach 1:
The patent changes the temperature parameter of the magnetic media during the recording process. By locally heating the media to elevated temperatures, the magnetic coercivity is temporarily reduced, allowing small write heads to successfully record to high coercivity media. After recording, the media cools and the coercivity increases, providing thermal stability for data retention.
Solution Approach 2:
The heating and cooling of the magnetic media occurs periodically during the recording process. The media is heated above the Curie temperature during writing, then allowed to cool below the Curie temperature for data stabilization, creating a periodic thermal cycle that enables high-density recording with small write heads.
2Stability of the object's composition
If the magnetic media coercivity is increased to ensure thermal stability of recorded bits, then the data retention is improved, but the magnetic write field required to record increases
Solution Approach 1:
The patent temporarily changes the temperature parameter of the magnetic media during recording. By heating the media above its Curie temperature, the coercivity is temporarily reduced to allow writing with small write heads. After recording, the media is allowed to cool below the Curie temperature, restoring high coercivity and ensuring thermal stability of the recorded data.
3Reliability
If thermal annealing is applied to the optical transducer antenna, then the transducer performance is improved, but surrounding magnetic structures may be damaged by heat
Solution Approach 1:
The patent segments the thermal treatment process by applying heat locally and selectively to the optical transducer antenna region only. The heating is spatially segmented to affect only the antenna that requires annealing, while magnetic structures are protected through temporal segmentation by controlling the duration and timing of the thermal exposure.
Solution Approach 2:
The patent uses an intermediary approach by applying thermal energy through the magnetic write pole structure itself, which acts as a heat conduction path. The write pole is heated to the annealing temperature and transfers heat to the optical transducer antenna, enabling indirect thermal treatment that protects surrounding magnetic structures from direct exposure to high temperatures.
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 the recording of smaller data bits with improved magnetic stability by using a thermally conductive, electrically insulating layer to facilitate annealing of the optical near-field transducer antenna, allowing for efficient heat transfer and preserving the integrity of the read element, thus overcoming the limitations of smaller write heads and higher media coercivity.
Implementation Method 1
A layer of thermally conductive, electrically insulating material is formed in the magnetic write head so as to contact the optical near field transducer
Implementation Method 2
forming a heating element, forming a layer of thermally conductive, electrically insulating material over the heating element
Implementation Method 3
an optical near field transducer is used to locally heat the magnetic media just at the point of recording. This heating of the magnetic media temporarily lowers the magnetic coercivity
Data Source
AI summary
A method for annealing a metal antenna of a near field optical transducer of a magnetic write element without inadvertently heat damaging the read element. A heating element is placed within a write head build in a cerf region outside of the active area of the read and write heads. A layer of thermally conductive, electrically insulating material is formed over the heating element to separate the heating element from the antenna. The thermally conductive, electrically insulating layer is preferably in contact with the antenna. A current can be applied to the heating element to heat the antenna to a temperature that is at or above the operating temperature of the optical transducer. After annealing, the heater element can be removed by the lapping process that is used to define the media facing surface of the head.