Thin-Film Magnetic Head Heater Shield Slit Design
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Solution Overview
Problem
Existing thin-film magnetic heads face challenges in maintaining reading performance due to heat propagation from heaters used to control magnetic spacing, which can lead to thermal asperity and degradation of signal recording and reproducing abilities, especially in high-density magnetic disk drives where MR read head elements are sensitive to temperature changes.
Innovation Solution
A thin-film magnetic head design featuring a heater integrated into the overcoat layer, with a slit area made of lower thermal conductivity material that limits heat propagation to the MR read head element, and strategically positioned to minimize heat absorption by the shield area, allowing for controlled magnetic spacing adjustment without degrading reading performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a heater is formed adjacent to the transducer in the slider substrate or between the slider substrate and the transducer, then the magnetic spacing can be controlled by thermal expansion, but the heat propagates to the MR read head element and degrades reading performance
Solution Approach 1:
A heat insulating layer is introduced as an intermediary between the heater and the MR read head element. This layer has low thermal conductivity and acts as a thermal barrier, preventing heat from the heater from propagating to the sensitive MR read head element while allowing the heater to still perform its function of controlling magnetic spacing through thermal expansion of the slider substrate.
Solution Approach 2:
The slider substrate is divided into distinct functional regions: a heater formation region for magnetic spacing control, an MR read head element formation region for reading operations, and a heat insulating layer region between them. This segmentation allows each region to perform its specific function while preventing harmful heat interaction between the heater and the read head element.
2Productivity
If the magnetic spacing is reduced to improve signal recording ability, then data storage capacity increases, but thermal asperity occurs due to frictional heat from contact between the protruded magnetic head element and the magnetic disk surface
Solution Approach 1:
The magnetic spacing is dynamically adjusted by changing the temperature parameter of the slider substrate through heater activation. By controlling the temperature increase, the thermal expansion of the slider substrate is controlled, which in turn controls the protrusion of the magnetic head element and thus the magnetic spacing. This allows optimization of signal recording ability while preventing thermal asperity through precise parameter control.
3Use of energy by moving object
If the heater is positioned close to the MR read head element to improve heating efficiency, then magnetic spacing control is enhanced, but the reading performance deteriorates due to temperature sensitivity of the MR read head element
Solution Approach 1:
The heat insulating layer serves as a thermal intermediary that allows the heater to be positioned relatively close to the MR read head element for efficient heating of the slider substrate, while simultaneously blocking direct heat transfer to the temperature-sensitive MR read head element, thus maintaining reading performance.
Solution Approach 2:
Different regions of the slider substrate have different thermal properties: the heater formation region can be heated efficiently, while the MR read head element formation region is protected from excessive heat through the heat insulating layer. This local differentiation of thermal quality allows simultaneous optimization of heating efficiency and reading performance.
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 effectively limits heat propagation to the MR read head element, maintaining reading performance and preventing thermal asperity, while allowing for precise adjustment of magnetic spacing using the TPTP phenomenon, thus enhancing the reliability and efficiency of high-density data storage operations.
Implementation Method 1
a heater that heats at least during the magnetic read head element or the magnetic write head element in operation and is formed in the overcoat layer
Implementation Method 2
the heat caused by eddy-current loss is generated in upper and lower pole layer. An overcoat layer expands thermally, and TPTP (Thermal Pole Tip Protrusion) phenomenon occurs, where the magnetic head element protrudes toward the magnetic disk surface
Implementation Method 3
a slit area that splits the shield area in a shield length direction and is made of lower thermal conductivity material than the one of the shield area
Data Source
AI summary
The present invention relates to a thin-film magnetic head with a heater. A thin-film magnetic head includes a substrate, a magnetic read head element that has a shield area and is formed on the substrate, a magnetic write head element that has a pole area and is formed on the opposite side of the substrate with respect to the magnetic read head element, an overcoat layer that covers the magnetic read head element and the magnetic write head element and is formed on the substrate, a heater that heats at least during the magnetic read head element or the magnetic write head element in operation and is formed in the overcoat layer, and a slit area that splits the shield area in a shield length direction and is made of lower thermal conductivity material than the one of the shield area.