Write Coil Current Adjustment for HAMR Reader Instability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Reader instability in heat-assisted magnetic recording (HAMR) devices, induced by previous write operations, leads to increased bit error rates and potential drive failures, as existing error recovery methods like thermal annealing are not effective against magnetic field-induced instability.
Innovation Solution
Adjusting the write power applied to the magnetic write coil and compensating with changes in laser power and clearance heater current to mitigate write-induced reader instability, thereby reducing subsequent read errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If write power is increased to improve write performance, then write capability is improved, but reader instability increases leading to higher bit error rates
Solution Approach 1:
The patent applies dynamics by making the write current adjustable and adaptive rather than fixed. The system dynamically modifies write current parameters (amplitude, pulse width, frequency) based on real-time read stability feedback, allowing the write operation to adapt its strength to prevent reader instability while maintaining effective write capability when conditions permit.
Solution Approach 2:
The patent implements feedback by using the read operation to detect instability caused by previous write operations. The read stability measurement feeds back to the write control mechanism, which then adjusts subsequent write current parameters to prevent instability, creating a closed-loop control system that balances write performance with read reliability.
2Force
If write current amplitude is increased to improve magnetic field strength, then write capability is improved, but reader instability is induced
Solution Approach 1:
The patent applies parameter changes by systematically varying write current parameters (amplitude, pulse width, frequency) to find optimal settings that provide sufficient magnetic field strength for writing without inducing reader instability. The system can adjust these parameters independently or in combination based on the severity and type of instability detected.
Solution Approach 2:
The patent makes the magnetic field strength dynamic rather than static. The write current amplitude is adjusted in real-time based on feedback from read operations, allowing the system to use higher amplitudes when stable and reduce them when instability is detected, optimizing both write capability and read reliability.
3Duration of action of moving object
If write pulse width is increased to improve magnetic field duration, then write capability is improved, but reader instability increases
Solution Approach 1:
The patent applies parameter changes by adjusting the write pulse width (duration) as a controllable variable. The system can extend or reduce pulse width based on the specific instability conditions detected during reading, allowing optimization of magnetic field exposure time to achieve effective writing while minimizing residual effects that cause reader instability.
4Speed
If write frequency is increased to improve writing speed, then productivity is improved, but reader instability is induced
Solution Approach 1:
The patent applies dynamics by making write frequency adjustable rather than fixed. The system can dynamically change the frequency of write operations based on feedback from read stability measurements, allowing higher frequencies for improved productivity when stable and lower frequencies when instability is detected, optimizing both speed and reliability.
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 approach effectively reduces the occurrence of read errors and stabilizes read performance by backing off write power, which helps in maintaining data integrity and preventing drive failures.
Implementation Method 1
an energy source that heats the media while recording
Implementation Method 2
a magnetic write coil
Data Source
AI summary
Data is written to a recording medium via a read/write head. Subsequent to the writing, the data is read via a read transducer of a read/write head. An instability indicator is derived based on measurements performed while the reading the data. If the instability indicator exceeds a threshold, a current applied to a write coil of the read/write head is changed for subsequent write operations.