Vertical Anisotropy Ferrimagnetic MRAM Reducing Critical Current
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional magnetic random access memory (MRAM) with horizontal anisotropy magnetoresistance elements faces limitations in cell density and power consumption due to the need for quadrature currents to change magnetization directions, which affects neighboring cells and increases power consumption.
Innovation Solution
A magnetic random access memory with a vertical anisotropy ferrimagnetic structure, eliminating the biasing layer and using a modified Landau-Lifshitz-Gilbert equation to calculate critical current values under external magnetic fields, reducing power consumption by optimizing the included angle, coupling constant, and anisotropy energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional horizontal anisotropy magnetoresistance elements are used with quadrature currents to change magnetization directions, then data storage function is achieved, but cell density is restricted and power consumption increases
Solution Approach 1:
The patent transitions from horizontal anisotropy magnetoresistance elements to vertical anisotropy ferrimagnetic elements, changing the dimension of magnetization orientation from in-plane to out-of-plane. This dimensional change enables higher cell density by reducing the area required per cell while maintaining data storage functionality through vertical magnetization switching instead of horizontal.
Solution Approach 2:
The patent changes the fundamental parameter of anisotropy type from horizontal to vertical, and modifies the magnetic material composition to achieve vertical anisotropy. This parameter change in the magnetic element structure enables more efficient current utilization and higher cell density without requiring quadrature current configurations.
2Reliability
If conventional horizontal anisotropy magnetoresistance elements with quadrature currents are used, then magnetization switching is achieved, but power consumption increases
Solution Approach 1:
By switching from horizontal to vertical anisotropy magnetoresistance elements, the patent changes the dimension of magnetization switching from in-plane to out-of-plane. This enables more efficient spin transfer torque switching with lower critical current, reducing power consumption while maintaining reliable magnetization switching functionality.
Solution Approach 2:
The patent modifies the anisotropy parameter from horizontal to vertical and adjusts material composition to achieve vertical anisotropy. This parameter change reduces the critical current required for magnetization switching, thereby reducing power consumption while ensuring reliable switching operation.
3Reliability
If biasing layer is included in conventional MRAM structure, then pinned layer magnetization is secured, but volume of the entire MRAM increases
Solution Approach 1:
The patent extracts and removes the biasing layer from the conventional MRAM structure by transitioning to vertical anisotropy elements. The vertical anisotropy inherently provides the necessary magnetic field stabilization without requiring an additional biasing layer, thus reducing the overall device volume while maintaining pinned layer magnetization stability.
Solution Approach 2:
The vertical anisotropy ferrimagnetic structure serves multiple functions simultaneously: it provides both the pinned layer magnetization stability and eliminates the need for a separate biasing layer. This multi-functionality reduces structural complexity and device volume while maintaining the necessary magnetic field control for reliable operation.
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 reduces the critical current, decreases power consumption, and improves manufacturing efficiency by simplifying the MRAM structure with fewer layers, achieving lower power consumption and increased cell density.
Implementation Method 1
Spinning orientations of a spin-polarized current applied to the magnetic random access memory causes magnetization precession and switching in the free layer
Implementation Method 2
A method of reducing a critical current in a magnetic random access memory comprises using a modified Landau-Lifshitz-Gilbert equation to produce a transitional equation describing a net magnetization of dynamics
Data Source
AI summary
A magnetic random access memory includes a substrate, a free layer and a spacer layer. The substrate and the free layer are made of a vertical anisotropy ferrimagentic thin film. The spacer layer is sandwiched between the substrate and the free layer and is made of an insulating layer. The method uses a modified Landau-Lifshitz-Gilbert equation to obtain a critical current value as a function of exchange coupling constant. The critical current value is predictable under several external magnetic fields being applied. When the exchange coupling constant is proportionally varied, the critical current value is reduced to a third of its original value under an optimum state.