Asymmetric Spin Junction Interface for Stable Domain Wall Motion
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Solution Overview
Problem
Conventional spin devices with symmetrical magnetic seed and free layers experience unstable magnetic domain wall movement due to edge defects, leading to jumping phenomena and operational noise, making them unreliable for magnetic field sensing.
Innovation Solution
A spin device with a magnetic seed layer structure where the magnetic device incorporates a magnetic seed layer with a non-magnetic heavy metal and a magnetic free layer with vertical magnetic anisotropy, where the seed layer is narrower than the free layer, guiding domain wall movement away from the edges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a symmetrical structure is used for magnetic seed layer and magnetic free layer, then the device structure is simple and easy to manufacture, but the magnetic domain wall movement becomes unstable and exhibits jumping phenomena due to edge defects
Solution Approach 1:
The patent applies asymmetry by making the magnetic seed layer narrower than the magnetic free layer. This asymmetric width configuration eliminates the edge defects present in symmetrical structures, as the magnetic domain wall movement is confined to the wider free layer region away from the narrow seed layer edges, thereby stabilizing the domain wall movement and preventing jumping phenomena.
2Device complexity
If the magnetic domain wall moves at the edge region of the magnetic free layer, then the device structure is simple, but the edge defects cause jumping phenomena and increase operational noise
Solution Approach 1:
The patent applies local quality by creating a specific width relationship between layers: the magnetic seed layer is made narrower than the magnetic free layer. This local dimensional variation ensures that the magnetic domain wall moves in the central region of the wider free layer, away from the edge regions where defects would cause jumping and noise, thus eliminating harmful operational noise without complicating the overall device structure.
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
Ensures stable and reversible magnetic domain wall movement, reducing operational noise and enhancing the reliability of spin-based devices like memory devices and sensors.
Implementation Method 1
when spin transfer torque is used, the resistance of the spin device is determined by the magnetization direction of the free layer and the pinned layer
Implementation Method 2
the spin device can be used as a magnetic sensor when the Hall voltage due to the movement of the magnetic domain in a ferromagnetic material is detected
Implementation Method 3
a magnetic domain wall of the magnetic free layer moves at a region abutting the magnetic seed layer
Implementation Method 4
an oxide layer formed on the magnetic free layer for imparting the vertical magnetic anisotropy to the magnetic free layer
Data Source
AI summary
A spin device is disclosed in which a magnetic domain wall is moved to the center region of a magnetic free layer. The magnetic domain wall is moved and the perpendicular magnetic anisotropy is changed by avoiding a number of defects distributed at the edge or edge region of the magnetic free layer. So, stable operation of the spin device is secured.