Magnetic Head Temperature Control for Track Density
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Solution Overview
Problem
Magnetic heads for perpendicular magnetic recording face challenges in reducing leakage magnetic fields and improving track density due to return magnetic fields and side shields, leading to erasure or deterioration of recorded information across multiple tracks and adjacent tracks.
Innovation Solution
Incorporation of a temperature control element unit with heat absorbing and radiating portions, utilizing N-type and P-type semiconductors connected to electrodes, which control temperature distribution along the main pole to manage coercive force and reversed magnetic fields, thereby reducing erasure and improving track density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If side shields are provided on both sides of the main pole to reduce leakage magnetic field, then erase width control is improved, but recorded information in adjacent tracks is erased or deteriorated due to return magnetic field
Solution Approach 1:
The patent applies local quality by creating a temperature gradient at specific locations on the main pole. The tip portion is heated to a higher temperature than the base portion, which locally modifies the magnetic properties only where needed. This allows the side shields to effectively control erase width at the heated tip region without causing widespread erasure in adjacent tracks, as the thermal effect is concentrated locally rather than distributed throughout the entire magnetic head structure.
Solution Approach 2:
The patent utilizes parameter changes by dynamically adjusting the temperature of the main pole through controlled heating. By changing the temperature parameter of the main pole tip portion, the magnetic properties (such as coercive force) are modified in real-time. This enables precise control over the magnetic field distribution and erase width, preventing information loss in adjacent tracks while maintaining effective erase width control where required.
2Object-affected harmful factors
If interval between side shield and side surface of main pole is wide, then erase width control is improved, but magnetic flux from narrowed portion erases recorded information in adjacent track
Solution Approach 1:
The patent applies local quality by concentrating the heating effect specifically at the tip portion of the main pole where the magnetic flux originates. This localized thermal modification creates a zone of altered magnetic properties precisely at the critical interface between the main pole and adjacent tracks. The side shields can therefore be positioned with appropriate spacing without causing adjacent track erasure, as the thermal confinement limits the spread of harmful magnetic flux effects.
3Loss of information
If temperature of main pole is controlled to manage coercive force, then erasure is suppressed, but additional control mechanism increases device complexity
Solution Approach 1:
The patent merges the temperature control function with the existing magnetic head structure by integrating the heating element directly into the main pole assembly. The heating mechanism is combined with the magnetic pole structure itself, allowing simultaneous thermal and magnetic control from a unified component. This integration reduces overall device complexity compared to having separate, independent temperature control and magnetic field generation systems.
Solution Approach 2:
The patent applies universality by designing the main pole to serve multiple functions: it generates the magnetic field for recording and simultaneously acts as a heating element for temperature control. The main pole structure is made multi-functional, combining magnetic field generation and thermal management in a single component. This eliminates the need for additional dedicated temperature control mechanisms, thereby reducing device complexity while achieving effective suppression of data deterioration.
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 temperature control element unit effectively narrows the erase region of the main pole, allowing for increased recording density by suppressing data deterioration and erasure in adjacent tracks, enhancing track pitch and overall recording capacity.
Implementation Method 1
N-type and P-type semiconductors connected to electrodes, which control temperature distribution along the main pole
Data Source
AI summary
According to one embodiment, a magnetic head includes a main pole, a write shield pole on a trailing side of the main pole, a recording coil, and a temperature control element unit. The temperature control element unit includes a first electrode on a leading side of the main pole and on both sides of a track of the main pole, a second electrode on the leading side of the main pole and on a track center of the main pole, an N-type semiconductor and a P-type semiconductor connected to the first and second electrodes, and a wiring portion which applies a current via the second electrode, N-type semiconductor, first electrode, P-type semiconductor, and second electrode. The first and second electrodes form a heat absorbing portion and a heat radiating portion.