Microwave-Assisted Magnetic Head With Inclined Dielectric Layer
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Solution Overview
Problem
Conventional magnetic recording technologies face challenges in achieving high density recording due to thermal fluctuations, limited saturation magnetic flux density, and complexity in thermal assisted magnetic recording methods, which affect signal stability and recording performance.
Innovation Solution
A thin film magnetic head design incorporating a microwave radiator between the main and auxiliary poles, with a nonmagnetic dielectric layer having an inclined surface to direct the microwave field towards the main pole, reducing the perpendicular magnetic field required for magnetization reversal and enhancing recording density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the perpendicular magnetic anisotropic energy Ku is increased to improve thermal stability, then the thermal stability index S improves, but the coercive force Hc increases making magnetization reversal more difficult
Solution Approach 1:
The patent applies microwave-frequency alternating magnetic fields (periodic action at GHz frequencies) to the recording medium during the writing process. This periodic magnetic field interacts with the magnetic moments in the recording layer, enabling magnetization reversal through resonant excitation and spin transfer torque, thereby reducing the required perpendicular magnetic field intensity despite high coercive force
Solution Approach 2:
The patent changes the magnetic field application parameters by introducing time-varying microwave-frequency magnetic fields in addition to the static perpendicular field. This parameter change allows exploitation of ferromagnetic resonance and dynamic magnetic effects to achieve magnetization reversal at lower peak field intensities
2Force
If the saturation magnetic flux density Bs is increased to improve recording magnetic field intensity, then the perpendicular recording magnetic field strength improves, but the material selection is limited by the practical upper limit of approximately 2.4 T
Solution Approach 1:
The patent introduces microwave-frequency magnetic fields as an intermediary mechanism to achieve magnetization reversal. Instead of relying solely on high-intensity static magnetic fields from the magnetic monopole, the microwave field acts as a mediator that provides additional torque and resonant excitation, enabling reversal with lower peak field requirements and greater material flexibility
3Manufacturing precision
If the thickness and width of magnetic monopoles are reduced to increase recording density, then the recording density improves, but the generated perpendicular magnetic field intensity is diminished
Solution Approach 1:
The patent compensates for the reduced magnetic field intensity from miniaturized monopoles by applying microwave-frequency periodic magnetic fields. This periodic action provides additional magnetic torque and resonant effects that enhance the total magnetic field effect on the recording medium, maintaining effective magnetization reversal capability despite the smaller monopole dimensions
Solution Approach 2:
The patent employs a composite approach combining the magnetic monopole structure with microwave radiation generation capabilities. This composite system integrates both static magnetic field generation and dynamic microwave field generation, creating a hybrid writing mechanism that overcomes the limitations of reduced monopole size
4Force
If thermal assisted magnetic recording is implemented to reduce coercive force during recording, then the required magnetic field for magnetization reversal decreases, but the system structure becomes extremely complicated and expensive requiring both magnetic and optical elements
Solution Approach 1:
The patent extracts and eliminates the optical heating components from the thermal assisted recording system, retaining only the magnetic field generation elements. By using microwave-frequency electromagnetic fields generated by planar transmission lines integrated with the magnetic head, the patent achieves magnetic field enhancement without requiring separate optical paths, lenses, or light sources, thereby dramatically simplifying the system structure while maintaining the benefit of reduced coercive force requirements
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 design improves recording density by reducing the perpendicular magnetic field needed for magnetization reversal, stabilizing the recording process, and simplifying the recording system by eliminating the need for complex thermal assisted methods.
Implementation Method 1
a microwave band high frequency magnetic field is applied to a magnetic recording medium
Implementation Method 2
a nonmagnetic dielectric layer having an inclined surface by which a microwave radiated from a microwave radiator is bent
Data Source
AI summary
A gap between a main pole and auxiliary pole composing a thin film magnetic head having a microwave assisted function of the present invention is filled with a nonmagnetic dielectric layer to embed a microwave radiator. The nonmagnetic dielectric layer has an inclined surface at a end on a side of an opposing medium surface by which the microwave radiated from the microwave radiator to be bent toward the main pole, whereby the microwave magnetic field generated from the microwave generator can be gathered immediately below the main pole, further improving the microwave assisted effect.