HAMR Dual-Layer Media for Three-State Single-Pass Recording
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current tri-state magnetic recording technologies face challenges in achieving high areal storage density capacity and signal-to-noise ratio due to noise issues and increased writing time, particularly in single-pass recording processes using heat-assisted magnetic recording (HAMR) devices.
Innovation Solution
A HAMR device is configured to implement a single-pass recording process that encodes three logical states on a single pass over a data track, utilizing stacked magnetic recording layers with different characteristics to achieve neutral polarity regions between data bits, thereby improving signal-to-noise ratios and reducing noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dual-pass write process is used to encode data on dual-layer recording media, then three logical states can be recorded, but writing time increases significantly and noise increases due to head misalignment
Solution Approach 1:
The recording media is divided into two separate magnetic layers with different Curie temperatures, allowing each layer to be written independently during a single pass. The upper layer (lower Tc) and lower layer (higher Tc) are selectively magnetized based on the write head temperature profile, enabling three-state encoding without requiring two separate passes.
Solution Approach 2:
The invention utilizes temperature as a control parameter to selectively write to different layers. By adjusting the write head temperature during a single pass, the system can target the upper layer at lower temperatures and the lower layer at higher temperatures, achieving three-state recording in one pass while maintaining alignment accuracy.
2Productivity
If AC erase is used to create zero polarity state in single-layer media, then three logical states can be encoded, but noise is high enough that net ADC gains have not been realized
Solution Approach 1:
The invention transitions from single-layer to dual-layer recording media, adding a vertical dimension to the storage structure. By stacking two magnetic layers with different Curie temperatures, the system can encode three logical states (positive, zero, negative) with significantly improved signal-to-noise ratio, as the layered structure provides better magnetic isolation and reduced noise compared to AC erase in single-layer media.
3Reliability
If dual-pass writing is used on dual-layer media, then three logical states can be recorded, but head misalignment causes increased noise and unintentional adjacent track overwrite
Solution Approach 1:
The recording media is divided into two separate magnetic layers with different Curie temperatures, allowing each layer to be written independently during a single pass. The upper layer (lower Tc) and lower layer (higher Tc) are selectively magnetized based on the write head temperature profile, enabling three-state encoding without requiring two separate passes.
Solution Approach 2:
The system prepares the write head with a controlled temperature profile before passing over the media. By pre-heating the write head to specific temperatures during the single pass, the system can selectively activate writing to the upper or lower layer based on which Curie temperature threshold is reached, ensuring precise layer selection without misalignment.
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 solution enables crisp, distinguishable boundaries between positive and negative polarity regions, significantly improving signal-to-noise ratios and potentially increasing areal storage density capacity by allowing for the recording of three logical states in a single pass, thus overcoming the limitations of existing technologies.
Implementation Method 1
heat-assisted magnetic recording (HAMR) device
Implementation Method 2
magnetizing bits with positive and negative polarity while the zero state is created by rapidly pulsing the write current between positive and negative polarity within a single bit
Data Source
AI summary
A heat-assisted magnetic recording (HAMR) device is configured to write regions of neutral polarity on a magnetic media during a same pass of the recording head in which other regions are written of positive polarity and negative polarity. The various disclosed write techniques may facilitate creation of “zero state” (substantially net zero polarity) transition zones between each pair of data bits of opposite polarity and/or may facilitate the encoding of three different logical states (e.g., 1, 0, and −1) on the media.