Microwave Assisted Magnetic Head for High Density Recording
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Solution Overview
Problem
Current magnetic recording technologies face challenges in achieving high-density recording due to limitations in signal-noise ratio, coercive force, and complexity in thermal assisted magnetic recording methods, particularly with the need for complex configurations and instability in perpendicular recording systems.
Innovation Solution
A microwave assisted magnetic head with a novel configuration featuring a main pole, shielded pole, and a microwave radiation waveguide made of conductive nonmagnetic material in the recording gap, connected via an electrical insulation film, which generates a microwave band resonant magnetic field aligned with the ferromagnetic resonant frequency of the recording medium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If thermal assisted magnetic recording (TAMR) is used to reduce coercive force for high density recording, then recording density can be improved, but device complexity increases due to the need for both magnetic and optical elements
Solution Approach 1:
The patent replaces the optical system (laser) used in TAMR with a microwave electromagnetic field system. The microwave radiation waveguide generates an AC magnetic field at ferromagnetic resonant frequency that penetrates the recording medium to reduce coercive force, eliminating the need for optical elements while achieving the same effect of lowering coercive force for high density recording.
Solution Approach 2:
The patent changes the physical parameter from optical frequency to microwave frequency (ferromagnetic resonant frequency). By operating at the ferromagnetic resonant frequency of the recording medium, the AC magnetic field from the microwave waveguide efficiently reduces coercive force through resonant interaction, achieving parameter-based differentiation from TAMR.
2Productivity
If thermal assisted magnetic recording (TAMR) is used to enable high density recording, then recording density can be improved, but manufacturing cost increases due to complex configuration
Solution Approach 1:
The patent replaces the complex optical system (laser source, optical path, optical elements) with a simpler microwave electromagnetic field system. The microwave radiation waveguide can be integrated into the magnetic head structure using conventional microwave technology, significantly reducing manufacturing complexity and cost while enabling high density recording.
3Productivity
If the thickness and width of the magnetic pole are reduced to increase recording density, then recording density can be improved, but the perpendicular magnetic field intensity is reduced
Solution Approach 1:
The patent merges two magnetic field generation mechanisms: the perpendicular magnetic field from the miniaturized magnetic pole and the in-plane AC magnetic field from the microwave radiation waveguide. The microwave-generated AC field compensates for the reduced field intensity from the smaller pole, maintaining sufficient total field strength while enabling higher recording density through the combined effect.
Solution Approach 2:
The patent creates a composite magnetic field system combining static perpendicular magnetic field (from magnetic pole) and dynamic AC magnetic field (from microwave). This composite approach allows the use of smaller magnetic poles for high density while the microwave component provides the additional field intensity needed for effective magnetization reversal.
4Reliability
If perpendicular recording magnetic field intensity is increased to improve magnetization reversal, then recording ability can be improved, but the recording element configuration becomes more complex
Solution Approach 1:
The patent substitutes the approach of increasing perpendicular field intensity (which would require larger or more complex magnetic poles) with a microwave electromagnetic field approach. The microwave radiation waveguide generates an AC magnetic field that resonates with the recording medium, providing enhanced magnetization reversal capability without increasing the complexity of the magnetic pole structure.
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 configuration simplifies the manufacturing process, enhances magnetic field intensity and gradient, and effectively overlaps AC magnetic fields to improve recording density and stability, overcoming limitations of existing technologies.
Implementation Method 1
the microwave band resonant magnetic field having either a ferromagnetic resonant frequency or an adjacent frequency of a magnetic recording medium
Implementation Method 2
a microwave radiation waveguide made of a conductive nonmagnetic material that is disposed in a recording gap
Implementation Method 3
a recording coil that is formed to generate a writing magnetic field from a tip of the main pole
Implementation Method 4
an electrical insulation magnetic film is disposed in the intermediate connection part
Data Source
AI summary
A microwave assisted magnetic head is formed to include a main pole magnetic layer including a main pole; a shielded magnetic layer including a shielded pole; a recording coil that is formed to generate a writing magnetic field from a tip of the main pole; and a microwave radiation waveguide made of a conductive nonmagnetic material that is disposed in a recording gap, the recording gap being a gap between the main pole and the shielded pole. The main pole magnetic layer and the shielded magnetic layer have an intermediate connection part that connects the layers at a depth-side, and an electrical insulation magnetic film is disposed in the intermediate connection part, and the main pole and the shielded pole are electrically connected with the microwave radiation waveguide that is disposed in the recording gap, which is the gap between the main pole and the shielded pole so that a simple configuration, with a relatively easy and efficient manufacturing process, is realized that overlaps AC magnetic fields in an in-plane direction of a microwave band, which is the same as, or close to, a ferromagnetic resonant frequency of a medium recording layer.