Vertical Magnetic Memory Element With Spin-Transfer Torque Read/Write Unit
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Solution Overview
Problem
Current domain wall movement-type magnetic memory elements face challenges in achieving higher magnetic unit density to increase memory capacity while maintaining cost-effectiveness.
Innovation Solution
The magnetic memory element design includes multiple magnetic units with easy magnetization axes intersecting the primary direction, connected through a read/write unit with nonmagnetic and pinned layers, allowing for domain wall movement by current flow between electrodes, optimizing domain wall movement and reducing errors through pinched-in portions and specific material configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If magnetic units are disposed in substrate normal direction, then memory capacity increases and cost is suppressed, but magnetic unit density cannot be increased further
Solution Approach 1:
The patent transitions from in-plane magnetic unit arrangement to vertical stacking in substrate normal direction, utilizing the third dimension (depth) to increase storage capacity. Multiple magnetic units are stacked vertically with their easy magnetization axes oriented in-plane, enabling higher density without proportionally increasing footprint area.
Solution Approach 2:
The magnetic storage space is divided into multiple separate magnetic units stacked vertically. Each magnetic unit can be independently controlled and read/written, allowing parallel operations and increasing overall capacity while maintaining manageable complexity through modular segmentation.
2Productivity
If current is applied to move domain walls, then data can be written and read, but current requirements increase with higher magnetic unit density
Solution Approach 1:
A read/write unit comprising a pinned layer and nonmagnetic layer is introduced as an intermediary between the magnetic units and the current control circuitry. This intermediary structure enables efficient spin-transfer torque oscillation (STT) for domain wall movement with reduced current requirements compared to direct current application.
Solution Approach 2:
The patent replaces direct mechanical/current-driven domain wall movement with spin-transfer torque mechanism. By using spin-polarized current flowing through the pinned layer and nonmagnetic layer, the magnetic moments experience torque that drives domain wall movement with lower current density requirements.
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 configuration enables higher magnetic unit density, stable domain wall movement, and reduced error occurrence during read/write operations, enhancing memory capacity without increasing costs.
Implementation Method 1
a read/write unit including a nonmagnetic layer and a pinned layer, the nonmagnetic layer being connected to the third magnetic unit, the pinned layer being connected to the nonmagnetic layer
Implementation Method 2
The first magnetic unit has an easy magnetization axis in a direction intersecting the first direction. The second magnetic unit has an easy magnetization axis in a direction intersecting the first direction.
Data Source
AI summary
A magnetic memory element includes a first magnetic unit, a second magnetic unit, a third magnetic unit, a read/write unit, a first electrode, a second electrode, a third electrode, a first current source, the second current source. The third magnetic unit is connected to one end in the first direction of the first magnetic unit and one end in the first direction of the second magnetic unit. The read/write unit includes a nonmagnetic layer and a pinned layer. The nonmagnetic layer is connected to the third magnetic unit. The pinned layer is connected to the nonmagnetic layer. The first current source causes a current to flow between the third electrode and at least one of the first electrode or the second electrode. The second current source causes a current to flow between the first electrode and the second electrode.