Microwave Assisted Magnetic Head Drive Current Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The quality of signals recorded on magnetic recording media deteriorates due to the superimposition of returning magnetic fields and microwave magnetic fields in microwave assisted magnetic recording, leading to increased bit error rates and reduced signal quality, especially with longer polarity reversal intervals.
Innovation Solution
A magnetic recording device with a microwave assisted magnetic head that controls the supply of drive current to the spin torque oscillator based on polarity reversal intervals, adjusting the duration and intensity of the microwave magnetic field to prevent signal quality deterioration by generating the microwave field only during specific threshold times or not at all during longer polarity reversal intervals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a microwave magnetic field is continuously applied to assist recording, then the recording capability is improved, but the signal quality deteriorates due to superimposition with returning magnetic fields during long polarity reversal intervals
Solution Approach 1:
The patent applies periodic action by controlling the microwave magnetic field to be applied only during specific time periods (when polarity reversal interval is short) and stopped during other periods (when polarity reversal interval is long). This temporal modulation of the microwave field application resolves the contradiction by eliminating harmful superimposition during long intervals while maintaining recording assistance during short intervals.
Solution Approach 2:
The patent implements dynamics by making the microwave magnetic field application state changeable based on the detected polarity reversal interval. The system dynamically adjusts between two states: applying the microwave field when the interval is short, and stopping it when the interval is long. This dynamic control optimizes both recording capability and signal quality under different operating conditions.
2Use of energy by moving object
If the microwave magnetic field is applied during long polarity reversal intervals, then power consumption is reduced by stopping the field, but signal quality deteriorates due to harmful superimposition
Solution Approach 1:
The patent employs feedback by detecting the polarity reversal interval and using this information to control the microwave magnetic field application. The system monitors the actual operating conditions (polarity reversal interval length) and adjusts the microwave field accordingly, creating a closed-loop control system that optimizes both power consumption and signal quality based on real-time conditions.
3Reliability
If the polarity reversal interval is long, then the bit error rate increases due to returning magnetic field superimposition, but shortening the interval increases recording density requirements
Solution Approach 1:
The patent applies parameter changes by modifying the microwave magnetic field application parameter (on/off state) based on the polarity reversal interval parameter. This allows the system to adapt to different recording density requirements while maintaining low bit error rates by selectively applying the microwave field only when the polarity reversal interval is appropriately short.
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 approach effectively prevents substantial deterioration in signal quality by optimizing the microwave magnetic field application, improving signal-to-noise ratios for both short and long polarity reversal intervals, thereby enhancing the recording performance and reducing power consumption.
Implementation Method 1
a spin torque oscillator provided near the main magnetic pole for generating a microwave magnetic field to apply to the magnetic recording medium in a superimposed manner on the recording magnetic field
Implementation Method 2
a microwave magnetic field of a frequency corresponding to the effective magnetic field (Heff) for magnetization of the recording layer of a magnetic recording medium is applied in the medium in-plane direction, whereby magnetization precession is excited in the recording layer
Implementation Method 3
a main magnetic pole for generating a recording magnetic field to apply to the magnetic recording medium while recording signals on the magnetic recording medium
Data Source
AI summary
A magnetic recording device includes a magnetic recording medium, a microwave assisted magnetic head having a main magnetic pole for generating a recording magnetic field, and a spin torque oscillator provided near the main magnetic pole for generating a microwave magnetic field, a recording current supply part for supplying a recording current to recording coils according to recording current waveform data, a drive current supply part for supplying a drive current to the spin torque oscillator, and a drive current control part for controlling supply of the drive current by the drive current supply part based on the data. Taking into consideration as an indicator whether a polarity reversal interval included in the data exceeds a threshold time, the drive current control part controls the drive current supply part so as not to substantially lower the quality of signals recorded on the magnetic recording medium.