PMR Write Head Structure With SOT Write Gap Current Confinement
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Solution Overview
Problem
Existing PMR write-head structures face challenges in confining bias current in SOT materials, leading to insufficient spin-orbit torque and increased device resistance, which degrades write head performance.
Innovation Solution
A PMR write-head structure with a write gap containing SOT material electrically isolated from the side shield, using dielectric oxide layers to concentrate current near the main pole, and synchronized bias current direction with the coil current to enhance spin-orbit torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the write gap material is used to induce spin-orbit torque, then the main pole switching rise time is improved, but the device resistance increases
Solution Approach 1:
The write gap is segmented into multiple regions: a first region with SOT material for torque induction, and a second region without SOT material for current confinement. This segmentation allows the bias current to be concentrated in the first region where it is needed, rather than dispersing throughout the entire write gap, thereby improving switching speed while controlling resistance
Solution Approach 2:
The SOT material is placed only in the first region of the write gap where it is most needed for inducing spin-orbit torque on the main pole, rather than uniformly across the entire write gap. This local placement optimizes the torque effect where it matters most while reducing overall device resistance
2Power
If the bias current is confined in the SOT material near the main pole, then the spin-orbit torque effect is enhanced, but the manufacturing complexity increases
Solution Approach 1:
The SOT material is integrated directly into the write gap structure, merging the torque-inducing function with the existing write head architecture. This integration allows current confinement and torque induction to be achieved through a unified structure rather than separate components, reducing manufacturing complexity
Solution Approach 2:
The write gap material serves as an intermediary structure that both induces spin-orbit torque and confines bias current through its specific geometric configuration. This intermediary role eliminates the need for additional complex current-confining structures, simplifying manufacturing
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
Improves main pole switching rise time by 18-24% and maintains device resistance below 10 ohms, enhancing writability and areal density capacity in hard disk drives.
Implementation Method 1
The WG can include an electrical conducting material that is capable of inducing a current-induced spin-orbit torque (SOT)
Data Source
AI summary
The present embodiments relate to a PMR write-head structure where the spin-orbit torque (SOT) material is in contact with the main pole in the write gap (WG). In addition, with the write shield (WS) electrically isolated from the side shield (SS) in the present designs, the current can be confined in the SOT material near the main pole, and the device resistance can remain within a reasonable range. It can be shown, using simulations, that the main pole switching rise time can be improved by 18˜24% using spin-orbit torque from heavy metals like platinum.