Magnetoresistive Element Spin Torque Magnetic Wall Writing
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Solution Overview
Problem
Current magnetic random access memory (MRAM) technologies face challenges in efficiently writing magnetic walls using external magnetic fields, which limits the speed and efficiency of data storage operations.
Innovation Solution
A semiconductor device comprising a magnetization free layer, a reference layer, and separated magnetization fixed layers with conductive non-magnetic layers, where current flow changes the state of electrical resistance between the reference layer and the magnetization free layer, allowing for novel writing methods by manipulating magnetic walls through spin torque and leakage magnetic fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If external magnetic field is used to write magnetic wall in conventional MRAM, then magnetic wall can be introduced, but writing speed and efficiency are limited
Solution Approach 1:
The patent replaces the external magnetic field method (mechanical/electromagnetic system) with a current-driven spin torque method. The magnetization free layer is structured to enable direct spin torque writing, where current flow generates spin polarization that acts on the magnetic wall, eliminating the need for external magnetic fields and achieving faster, more efficient writing operations.
Solution Approach 2:
The patent modifies the magnetic parameters of the magnetization free layer by controlling its thickness and composition to achieve perpendicular magnetic anisotropy. This parameter change enables the layer to respond to spin torque from current flow, allowing magnetic wall writing without external magnetic fields and improving both writing speed and energy efficiency.
2Speed
If current is increased to move magnetic wall, then writing speed improves, but power consumption increases
Solution Approach 1:
The patent optimizes the thickness and magnetic properties of the magnetization free layer to reduce the critical current density required for magnetic wall movement. By controlling the perpendicular magnetic anisotropy through layer thickness and composition, the device achieves efficient spin torque writing at lower current levels, improving both speed and power efficiency.
Solution Approach 2:
The patent creates localized magnetic properties in the magnetization free layer, with different regions having optimized thickness and composition to facilitate magnetic wall nucleation and movement. This local optimization allows magnetic wall movement with reduced current requirements compared to uniform structures.
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 approach enables efficient and power-effective writing operations by reducing the coercive force of the magnetization free layer, allowing for smaller current requirements and lower power consumption compared to traditional methods, while maintaining data integrity through controlled magnetic wall movement.
Implementation Method 1
a magnetic wall in a ferromagnetic body is moved by a current and further moved in a direction opposite to the direction of the current. Further, a magnetoresistive effect element that moves a magnetic wall using such a spin torque to perform writing has been described
Implementation Method 2
a magnetoresistive effect element that moves a magnetic wall using such a spin torque to perform writing
Data Source
AI summary
The present invention provides a magnetoresistive effect element which performs writing by a novel method. In a state in which a current does not flow in a magnetization free layer MFR, the magnetization free layer MFR has a magnetic wall MW1 on the side of a magnetization fixed layer MFX1. A magnetic wall MW2 is moved to the magnetic wall MW1 side by causing current to flow from the formed side of the magnetic wall MW1. Thus, an electrical resistance RMTJ between a reference layer REF and the magnetization free layer MFR changes from a low state to a high state.