Magnetic Memory Element With Reduced Cross-Sectional Area
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Solution Overview
Problem
Current magnetic memory elements face challenges in achieving high-density nonvolatile memory devices due to limitations in downsizing while maintaining effective magnetization reversal and oscillation frequencies.
Innovation Solution
A magnetic memory element configuration with a stacked body comprising ferromagnetic layers and nonmagnetic layers, where the cross-sectional area of the third ferromagnetic layer is smaller than the first stacked unit, allowing for increased current density and oscillation frequency, enabling efficient magnetization reversal and high-density memory operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the size of the magnetic memory element is reduced to achieve high-density memory, then the memory density increases, but the magnetization reversal efficiency and oscillation frequencies deteriorate
Solution Approach 1:
The patent applies local quality by creating a size gradient within the magnetic memory element structure. Specifically, the third ferromagnetic layer has a smaller cross-sectional area than the first stacked unit, concentrating the current density in this smaller region. This local concentration of current density enhances the spin-transfer torque effect and increases oscillation frequency in the critical region, thereby maintaining magnetization reversal efficiency even as the overall element size is reduced for higher memory density.
2Speed
If the cross-sectional area of the third ferromagnetic layer is reduced, then the current density increases and oscillation frequency increases, but the structural complexity increases
Solution Approach 1:
The patent segments the magnetic memory element into distinct functional units with different cross-sectional areas. The first stacked unit and the third ferromagnetic layer are structurally separated, allowing the third layer to have a smaller cross-section optimized for high-frequency oscillation while the first stacked unit maintains a larger cross-section for stable magnetization reversal. This segmentation enables independent optimization of each component's dimensions to achieve the desired oscillation frequency without excessive overall structural complexity.
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 configuration enables high-density nonvolatile memory devices with improved magnetization reversal efficiency and oscillation frequencies, facilitating effective data storage and retrieval.
Implementation Method 1
causing a rotating magnetic field generated from a precession of the magnetization of the third ferromagnetic layer to act on the second ferromagnetic layer
Implementation Method 2
a rotating magnetic field generated from a precession of the magnetization of the third ferromagnetic layer
Implementation Method 3
causing an electron whose spin is polarized by passing the current through the stacked body along the stacking direction to act on the second ferromagnetic layer
Data Source
AI summary
According to one embodiment, a magnetic memory element includes a stacked body including first and second stacked units stacked with each other. The first stacked unit includes first and second ferromagnetic layers and a first nonmagnetic layer provided therebetween. The second stacked unit includes third and fourth ferromagnetic layers and a second nonmagnetic layer provided therebetween. Magnetization of the second and third ferromagnetic layers are variable. Magnetizations of the first and fourth ferromagnetic layers are fixed in a direction perpendicular to the layer surfaces. A cross-sectional area of the third ferromagnetic layer is smaller than a cross-sectional area of the first stacked unit when cut along a plane perpendicular to the stacking direction.