Asymmetric Magnetic Memory Element Eliminates External Field
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Solution Overview
Problem
Existing magnetic memory points require an external magnetic field for programming, which poses practical implementation challenges and are not sensitive to low currents.
Innovation Solution
A magnetic memory point design where the conductive track is bent with arms meeting at a central portion, allowing programming by current flow between terminals A and B without an external magnetic field, utilizing a programmable magnetic layer with orthogonal magnetization, and a non-magnetic layer differing in thickness or composition, enabling magnetization orientation without external magnetic influence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an external magnetic field is applied for programming, then magnetization reversal can be achieved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent extracts and eliminates the external magnetic field requirement from the programming process. By designing the magnetic memory point with a specific geometric asymmetry in the pad structure, the invention achieves magnetization reversal through current flow alone, removing the need for external magnetic field generation equipment and simplifying the overall system complexity.
Solution Approach 2:
The magnetic memory point structure itself generates the necessary conditions for magnetization reversal through its geometric asymmetry. The asymmetric pad design creates different current path lengths and resistance values that automatically produce the required spin transfer torque effect when current flows through the device, making the system self-programming without external magnetic field assistance.
2Ease of manufacture
If conventional symmetric pad structure is used, then manufacturing is simpler, but programming requires external magnetic field and low current sensitivity is not achieved
Solution Approach 1:
The patent introduces geometric asymmetry in the pad structure with specific dimensional differences (L1≠L2, W1≠W2) to create unequal current path lengths and resistance values. This asymmetry is deliberately designed to enhance current-induced magnetization reversal efficiency and enable low-current programming while remaining compatible with standard fabrication processes.
Solution Approach 2:
The asymmetric dimensions are applied locally to specific regions of the pad structure (different lengths and widths in opposite directions from the central track) rather than uniformly across the entire device. This localized asymmetry creates the necessary conditions for directional magnetization control and low-current sensitivity without requiring complete restructuring of the manufacturing process.
3Device complexity
If reading and writing operations are combined, then device structure is simpler, but operation reliability decreases due to interference
Solution Approach 1:
The patent functionally segments the magnetic memory point into distinct writing and reading regions. The asymmetric pad structure with different dimensional characteristics in opposite directions creates inherent functional separation: one direction optimizes for writing (magnetization reversal) while the other optimizes for reading (magnetization detection), allowing both operations to proceed independently without interference.
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
Enables programming and reading of magnetic memory points in the absence of a magnetic field, with sensitivity to low currents and simplified production, allowing for efficient and low-current operation.
Implementation Method 1
Memory point programming is performed by flowing a current between terminals A and B... The passage of current from terminal A to terminal B imposes an orientation on the magnetization of the programmable layer. The passage of current from terminal B to terminal A imposes the opposite orientation.
Implementation Method 2
The conductive track is bent and comprises two arms with respective median axes. The angle between the median axes may be between 30° and 150°, preferably between 60° and 120°. The two arms meet at a central portion of the track. The plot is arranged on the central portion of the track in an off-center position relative to the median axes.
Data Source
Figure 1A~1C
Figure 2
Figure 3A~3B
AI summary
The invention relates to a magnetic memory element, including: a contact (31) comprising a magnetic layer portion (34) between a conductive layer portion (32) and a non-magnetic layer portion (36), the magnetic layer having a magnetization perpendicular to the plane of the layers, and an angled conductive track (42) comprising a central portion extended by two arms (44A, 44B), the contact being entirely arranged on the track, wherein, for each arm, a current flowing towards the contact along the median axis of the arm encounters the portion of the contact nearest to the arm primarily on the left thereof for one of the arms (44A), and primarily on the right thereof for the other arm (44B).