High-Damping Trailing Shield Seed Layer for MAMR Bit-Flipping Reduction
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Solution Overview
Problem
Existing MAMR write heads suffer from high bit-flipping rates and diminished AC field assistance due to oscillations in the free layer, which are not effectively addressed by current technologies.
Innovation Solution
Incorporating a high damping trailing shield seed layer doped with a rare earth element, such as CoFeHo, between the spin torque oscillator and the trailing shield, reduces the amplitude of additional AC fields and minimizes bit flipping by lowering the magnetic moment and increasing damping in the TS hot seed layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a spin torque oscillator device is used to produce high-frequency AC field for MAMR, then recording density is improved, but bit-flipping rate increases
Solution Approach 1:
A trailing shield hot seed layer is introduced as an intermediary component between the spin torque oscillator device and the trailing shield. This layer acts as a mediator to suppress unwanted oscillations and reduce bit-flipping while maintaining the AC field generation capability for high-density recording.
Solution Approach 2:
The trailing shield hot seed layer is doped with rare earth elements to fundamentally change its magnetic parameters, specifically achieving high damping characteristics. This parameter change allows the layer to suppress oscillations and reduce bit-flipping rate while preserving the MAMR recording density improvement.
2Power
If the free layer oscillates to provide AC field assistance, then writing capability is improved, but additional AC field oscillations increase bit-flipping
Solution Approach 1:
The trailing shield hot seed layer converts the harmful effect of free layer oscillations into a beneficial outcome. By being positioned adjacent to the free layer, it utilizes the oscillating magnetic field to drive its own high-damping oscillations, which then suppress the harmful bit-flipping effects while maintaining the useful AC field assistance for writing.
Solution Approach 2:
The trailing shield hot seed layer serves as an intermediary that decouples the harmful oscillation effects from the useful writing capability. It absorbs and dampens the problematic AC field oscillations while allowing the primary AC field assistance to function, thereby resolving the contradiction between writing power and bit-flipping.
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 high damping trailing shield seed layer effectively reduces bit flipping and maintains AC field assistance, enabling higher recording density and stability in magnetic recording media.
Implementation Method 1
a spin torque oscillator (STO) device is located next to or near the write element in order to produce a high-frequency AC field
Implementation Method 2
The trailing shield hot seed layer has an intrinsic damping from about 0.02 to about 0.2
Data Source
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AI summary
A microwave assisted magnetic recording (MAMR) write head includes a main pole and a trailing shield. A spin torque oscillator device is disposed between the main pole and the trailing shield. The spin torque oscillator device includes a free layer. A trailing shield hot seed layer is disposed between the spin torque oscillator device and the trailing shield. The trailing shield hot seed layer includes a magnetic material doped with a rare earth element. In certain embodiments, the trailing shield hot seed layer includes the rare earth element in an atomic percent content from about 2% to about 10% atomic percent. In certain embodiments, the trailing shield hot seed layer has an intrinsic damping from about 0.02 to about 0.2.