Magnetic Memory Domain Wall Pinning via Composite Layer
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Solution Overview
Problem
Magnetic memories with domain wall shifting technology face challenges in maintaining data stability due to external disturbances, requiring effective pinning mechanisms to prevent domain wall shifts, while also needing to increase capacity and reduce power consumption.
Innovation Solution
A magnetic memory design incorporating a pinning layer with nonmagnetic and magnetic phases, adjacent to a magnetic nanowire, where the pinning layer is formed with specific structures such as granular, dot-like, or striped configurations, and controlled by an electric field to manage domain wall pinning and shifting, allowing for reduced current requirements and increased memory density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pinning layer with nonmagnetic and magnetic phases is introduced to pin domain walls, then data stability is improved, but device complexity increases
Solution Approach 1:
The pinning layer is constructed as a composite material containing both nonmagnetic phases (e.g., Ru, Rh, Ir, Pt, Pd, Au, Ag, Cu, Al) and magnetic phases (e.g., Co, Ni, Fe, or their alloys), forming a heterogeneous structure that provides both mechanical stability and magnetic pinning functionality. This composite approach allows the layer to simultaneously achieve data stability through domain wall pinning while managing device complexity through material-level integration rather than separate structural components.
2Manufacturing precision
If physical notches or ion beam irradiation are used to form pinning sites, then manufacturing precision is improved, but ease of manufacture deteriorates
Solution Approach 1:
The patent replaces mechanical/physical methods (physical notching, ion beam irradiation) with a materials science approach. Instead of using mechanical processes to create pinning sites, the invention uses a pinning layer with specific nonmagnetic and magnetic phase compositions that inherently provide pinning functionality. This substitution eliminates complex fabrication steps while achieving precise domain wall pinning through material property control, thereby improving ease of manufacture while maintaining manufacturing precision.
3Reliability
If domain wall pinning is strengthened to prevent external disturbance, then reliability is improved, but energy consumption increases
Solution Approach 1:
The pinning layer exhibits local quality variations through its heterogeneous structure of nonmagnetic and magnetic phases. The nonmagnetic phases (Ru, Rh, Ir, Pt, Pd, Au, Ag, Cu, Al) and magnetic phases (Co, Ni, Fe, or their alloys) are distributed to create localized pinning sites with specific strengths. This local quality approach allows strong pinning where needed to prevent external disturbance while maintaining overall energy efficiency by concentrating pinning functionality rather than requiring uniform strong pinning across the entire magnetic nanowire 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
The solution effectively pins domain walls, reducing the current needed for shifts and enhancing memory capacity by controlling the pinning force through voltage application, thereby improving data stability and efficiency in magnetic memory devices.
Implementation Method 1
a pinning layer with nonmagnetic and magnetic phases, the pinning layer extending in an extending direction of the magnetic layer and being located adjacent to the magnetic layer
Implementation Method 2
a voltage generating unit configured to generate a voltage to be applied between the pinning layer and the electrode layer
Implementation Method 3
a current introducing unit configured to flow a shift current to the magnetic layer, the shift current causing the domain walls to shift
Data Source
AI summary
A magnetic memory according to an embodiment includes: a magnetic layer including a plurality of magnetic domains and a plurality of domain walls, and extending in a direction; a pinning layer formed with nonmagnetic phases and magnetic phases, extending in an extending direction of the magnetic layer and being located adjacent to the magnetic layer; an electrode layer located on the opposite side of the pinning layer from the magnetic layer; an insulating layer located between the pinning layer and the electrode layer; a current introducing unit flowing a shift current to the magnetic layer, the shift current causing the domain walls to shift; a write unit writing information into the magnetic layer; a read unit reading information from the magnetic layer; and a voltage generating unit generating a voltage to be applied between the pinning layer and the electrode layer.