Patterned Reader Shields for Cooler Magnetic Recording Heads
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Solution Overview
Problem
In hard-disk drive (HDD) operations, the elevated passive flying height due to additional heat from heat sources in Thermally Assisted Magnetic Recording (TAMR) and Microwave Assisted Magnetic Recording (MAMR) leads to higher temperature rise, causing performance degradation and reliability issues.
Innovation Solution
A PMR, TAMR, or MAMR read/write head with a patterned lower reader shield featuring a heating element and a magnetic shielding portion, along with a patterned thermal insulating layer that selectively absorbs heat, reducing temperature rise without affecting the desired thermal protrusion shape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional heat sources (laser, rf-oscillator, spin-torque device) are used in TAMR or MAMR to lower coercivity during write operations, then magnetic recording performance is improved, but temperature rise of the read/write head increases causing performance degradation and reliability issues
Solution Approach 1:
The reader shield is segmented into multiple regions with different thermal properties: a first region with high thermal conductivity and a second region with low thermal conductivity. This segmentation allows different parts of the shield to perform different functions - one region conducts heat away from the reader while another region provides thermal insulation where needed.
Solution Approach 2:
Different regions of the reader shield are assigned different thermal conductivities to address local thermal management needs. The first region has high thermal conductivity to conduct heat away from the reader, while the second region has low thermal conductivity to provide thermal insulation. This local differentiation of thermal properties optimizes heat management in specific areas without compromising overall performance.
2Length of stationary object
If passive flying height is increased to accommodate laser-induced writer protrusion in TAMR, then the head fits the media spacing budget, but temperature rise of the reader increases causing poorer performance
Solution Approach 1:
The reader shield is divided into regions with different thermal conductivities, allowing the structure to manage heat differently in various areas. This segmentation enables the shield to conduct heat away from the reader in some regions while providing insulation in others, addressing the thermal management issue caused by increased passive flying height.
Solution Approach 2:
The shield structure incorporates regions with locally optimized thermal properties. The first region has high thermal conductivity to conduct heat away from the reader, while the second region has low thermal conductivity to provide thermal insulation. This local quality differentiation allows the structure to accommodate the increased passive flying height while managing the resulting temperature rise.
3Temperature
If a thermal insulating layer is added to the reader shield to reduce heat absorption, then temperature rise is reduced, but the desired thermal protrusion shape of the writer may be affected
Solution Approach 1:
The thermal insulating layer is applied selectively to specific regions of the reader shield rather than uniformly across the entire shield. This segmentation allows the insulating layer to reduce heat absorption in areas where it benefits temperature management while leaving other regions unaffected, thereby preserving the desired thermal protrusion shape of the writer.
Solution Approach 2:
The thermal insulating layer is positioned in specific locations on the reader shield where it provides thermal management benefits without interfering with the writer's thermal protrusion shape. This local application of thermal insulation allows simultaneous optimization of temperature control and writer 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
The solution effectively reduces the temperature rise of the read/write head, enhancing performance and reliability by minimizing heat generation while maintaining the required thermal protrusion shape, as demonstrated by simulation results showing significant temperature reduction with minimal actuation efficiency loss.
Implementation Method 1
a patterned thermal insulating (heat absorbing) layer
Implementation Method 2
a patterned lower reader shield magnetically shielding its reader portion
Implementation Method 3
The heating element is formed on the lower reader shield
Data Source
AI summary
A PMR, TAMR or MAMR (Perpendicular Magnetic Recording, Thermally Assisted Magnetic Recording or Microwave Assisted Magnetic Recording) slider-mounted read/write head produces less heat during operation by using magnetic read shields in which are embedded a patterned layer of thermally absorbing material. At least one shield includes a heating coil which is used to adjust the fly-height of the slider by creating a thermal protrusion at the slider ABS. When additional sources of energy, such as laser heating, microwave heating or the write coil itself, are applied to the recording medium, the shields can overheat, adversely affecting their performance. The patterned layer of heat absorbing material reduces the flow of heat from the thermal heating coil to the air bearing surface (ABS) thus cooling the region around the write head while not adversely affecting the shape of the thermal protrusion.