STRAMR Device Width and Heat Dissipation
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Solution Overview
Problem
Existing STRAMR designs face challenges in operating at reduced temperatures and require high current densities for FCL magnetization flipping, leading to heat generation and reliability issues, while also being costly due to complex fabrication processes.
Innovation Solution
A STRAMR device with a wider cross-track width than the track width, incorporating a stack of layers including a non-spin polarization preserving layer, a spin polarization preserving layer, and an optional reference layer, where the FCL magnetization flips in response to spin torque, enhancing the write field and allowing for improved heat dissipation and simplified fabrication by defining the device width during the same process steps as the trailing shield width.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high current density is applied to flip FCL magnetization for STRAMR effect, then write field enhancement is improved, but heat generation increases and device reliability deteriorates
Solution Approach 1:
The patent extends the STRAMR device width in the cross-track direction (lateral dimension) beyond the traditional track width limitation. This dimensional expansion increases the volume available for heat dissipation laterally, reducing the temperature rise at the write gap where the FCL is located. The wider device structure allows heat to spread across a larger area, preventing localized overheating while maintaining the high current density needed for effective FCL magnetization flipping and write field enhancement.
2Ease of manufacture
If STRAMR device width is limited to track width, then fabrication complexity is reduced, but heat dissipation capability deteriorates
Solution Approach 1:
The patent defines the STRAMR device width in the cross-track direction to be substantially greater than the track width, utilizing the lateral dimension for thermal management. This approach maintains fabrication simplicity by using standard photolithography and deposition processes, while the extended width provides enhanced heat dissipation pathways. The device structure allows heat generated during operation to conduct laterally across the broader device footprint, reducing operating temperature without adding complex fabrication steps.
3Device complexity
If FCL width is matched to track width, then device complexity is minimized, but heat generation concentrates and reliability decreases
Solution Approach 1:
The patent extends the FCL width in the cross-track direction beyond the traditional track width boundaries. This lateral expansion distributes the heat generated during FCL magnetization flipping across a wider area, preventing heat concentration at the write gap. The extended FCL structure maintains alignment with the broader STRAMR device, allowing efficient heat conduction to the substrate and surrounding structures without requiring additional complex device components or layered structures.
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 reduces operating temperatures, enhances write field output, and simplifies the fabrication process, thereby improving device reliability and productivity by dispersing heat and reducing the risk of electromigration.
Implementation Method 1
a flux change layer (FCL) formed in a write gap (WG) between a main pole (MP) trailing side and a trailing shield (TS) has a magnetization that flips to a direction substantially opposite to the magnetic field in the WG as a result of spin torque generated by spin polarized electrons from an adjacent magnetic layer when a current (Ia) is applied
Implementation Method 2
the STO device has a width substantially greater than the side gap width to transmit heat generated by Ia away from the STO, reducing the local temperature and improving device reliability
Data Source
AI summary
A spin transfer torque reversal assisted magnetic recording (STRAMR) device is disclosed wherein a flux change layer (FCL) is formed between a main pole (MP) trailing side and a trailing shield (TS). The FCL has a magnetization that flips to a direction substantially opposing the write gap magnetic field when a direct current (DC) of sufficient current density is applied across the STRAMR device thereby increasing reluctance in the WG and producing a larger write field output at the air bearing surface. Heat transfer in the STRAMR device is enhanced and production cost is reduced by enlarging the STRAMR width to be essentially equal to that of the TS, and where the TS and STRAMR widths are formed using the same process steps. Bias voltage is used to control the extent of FCL flipping to a center portion to optimize the gain in area density capability in the recording system.