MAMR Stack Asymmetric Shape for Switch Time Reduction
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Solution Overview
Problem
Current magnetic recording heads face limitations in improving recording performance due to the switch time of the magnetic layer, which is influenced by the area to be switched at a location recessed from the media facing surface.
Innovation Solution
The magnetic recording head design includes a MAMR stack with a magnetic layer having a surface where the second side is substantially less than the first side, reducing the area to be switched and thereby decreasing the overall switch time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the magnetic layer has a conventional symmetric shape with equal sides, then the structural simplicity and ease of manufacture are maintained, but the switch time of the magnetic layer is increased due to larger area to be switched
Solution Approach 1:
The patent applies asymmetry by configuring the magnetic layer with an asymmetric cross-sectional shape where the second side length is substantially less than the first side length. This asymmetric geometry reduces the area of magnetic material that needs to be switched while maintaining structural feasibility, directly addressing the contradiction between reducing switch time and avoiding excessive shape complexity
2Loss of time
If the area of the magnetic layer at the recessed location is reduced, then the switch time is decreased, but the field gradient and write field strength may be compromised
Solution Approach 1:
The patent applies local quality by creating non-uniform distribution of magnetic material through the asymmetric shape. The magnetic layer has different dimensions at different locations - a larger first side length for maintaining field gradient and write field strength, and a smaller second side length for reducing switch time. This localized variation in geometry allows simultaneous optimization of both switching speed and magnetic field characteristics
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 reduces the switch time of the magnetic layer, enhancing recording performance by minimizing the area of the magnetic material to be switched, leading to improved areal density capability.
Implementation Method 1
The MAMR stack includes a magnetic layer, such as a spin torque layer (STL), which is magnetized by a bias current from the main pole to the MAMR stack during operation. The STL switches against the gap field when the bias current through the MAMR stack exceeds a certain threshold.
Data Source
AI summary
The present disclosure generally relates to data storage devices, and more specifically, to a magnetic media drive employing a magnetic recording head. The head includes a main pole, a trailing shield, and a MAMR stack including at least one magnetic layer. The magnetic layer has a surface facing the main pole, and the surface has a first side at a media facing surface (MFS) and a second side opposite the first side. The length of the second side is substantially less than the length of the first side. By reducing the length of the second side, the area to be switched at a location recessed from the MFS is reduced as a current flowing from the main pole to the trailing shield or from the trailing shield to the main pole. With the reduced area of the magnetic layer, the overall switch time of the magnetic layer is decreased.