Magnetic Head Main Pole With Nonmagnetic Film Gap
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Solution Overview
Problem
Current magnetic recording heads for perpendicular recording face challenges in increasing magnetic field intensity while preventing data overwrite to adjacent tracks, due to limitations in magnetic field gradient and saturation magnetic flux density, which hinder narrower track recording.
Innovation Solution
A magnetic head design featuring a main pole with a soft magnetic film on its trailing side and a nonmagnetic film interposed between the main pole and the soft magnetic film, where the thickness of both the main pole and nonmagnetic film increases in the depth direction from the air bearing surface, with the nonmagnetic film's angle greater than the main pole's angle, forming a magnetic gap that enhances magnetic field intensity and suppresses writing to adjacent tracks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a soft magnetic film is provided around the main pole to increase magnetic field gradient, then the magnetic field gradient is improved, but the magnetic field intensity is reduced due to the thickness of the soft magnetic film and saturation magnetic flux density
Solution Approach 1:
A nonmagnetic film is introduced as an intermediary layer between the main pole and the soft magnetic film. This nonmagnetic film prevents the soft magnetic film from directly contacting the main pole, thereby avoiding the reduction of magnetic field intensity caused by the soft magnetic film's saturation flux density, while still allowing the soft magnetic film to function in increasing the magnetic field gradient.
Solution Approach 2:
The structure is segmented into distinct functional layers: the main pole, the nonmagnetic film, and the soft magnetic film. This segmentation allows each layer to perform its specific function independently - the main pole generates the magnetic field, the nonmagnetic film prevents field intensity reduction, and the soft magnetic film enhances the magnetic field gradient.
2Force
If the thickness of the main pole is increased in the depth direction to increase magnetic field intensity, then the magnetic field intensity is improved, but the magnetic field gradient becomes less steep
Solution Approach 1:
The soft magnetic film is applied locally on the trailing side of the main pole rather than uniformly across the entire pole. This localized application creates a region of enhanced magnetic field gradient specifically where needed, while the main pole's increased thickness maintains overall magnetic field intensity.
3Object-generated harmful factors
If a magnetic shield film is provided to prevent leakage of magnetic field to adjacent tracks, then data overwrite to adjacent tracks is reduced, but the magnetic field intensity at the main pole is reduced
Solution Approach 1:
The nonmagnetic film acts as a mediator that prevents the magnetic shield film (soft magnetic film) from directly contacting the main pole. This intermediary layer ensures that the magnetic shield film can perform its function of preventing magnetic field leakage to adjacent tracks without reducing the magnetic field intensity generated by the main pole.
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 design effectively increases magnetic field intensity and reduces overwrite to adjacent tracks, improving recording density and performance by optimizing the magnetic field gradient and preventing data leakage.
Implementation Method 1
A recording current, in which the polarity is set in accordance with electrical signals, flows to the coil conductor, and causes a recording field having a corresponding current polarity to be generated by the main pole.
Implementation Method 2
A soft magnetic underlayer is disposed below the recording layer which forms part of the perpendicular recording medium, and this has the function of returning the magnetic flux acting on the recording layer to the sub-pole.
Implementation Method 3
a soft magnetic film on the side surface in the track width direction of the main pole as a method for increasing the magnetic field gradient
Data Source
AI summary
According to one embodiment, a magnetic head for perpendicular recording includes a main pole, a first soft magnetic film disposed on a trailing side of the main pole, and a first nonmagnetic film interposed between the main pole and the first soft magnetic film. A thickness of the main pole is increased in a depth direction from an air bearing surface using an inclination, and a thickness of the first nonmagnetic film increases in the depth direction from the air bearing surface. In another embodiment, an angle from a horizontal plane of an upper surface of the first nonmagnetic film is greater than an angle from a horizontal plane of a lower surface of the first nonmagnetic film in contact with the main pole. Other heads, methods, and systems are described according to more embodiments.