Perpendicular MRAM Element with L10 Alloy and Nitride Layer
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Solution Overview
Problem
Current magnetoresistive random access memory (MRAM) technologies face challenges in reducing the current required for magnetization reversal while maintaining high thermal disturbance resistance and achieving a high magnetoresistive ratio, particularly due to limitations in micropatterning and the use of materials with high magnetic anisotropic energy density.
Innovation Solution
A magnetoresistive element is designed with a nitride underlying layer having an NaCl structure, a ferromagnetic alloy with an L10 structure, and a perpendicular magnetization arrangement, which includes a first magnetic layer with magnetic anisotropy perpendicular to the film surface and a second magnetic layer with magnetic anisotropy perpendicular to the film surface, optimized for reduced current consumption and enhanced thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If micropatterning is advanced to reduce cell area, then device compactness is improved, but the magnetic field required for magnetization reversal increases
Solution Approach 1:
The patent changes the magnetization arrangement from in-plane to perpendicular, and uses L10 structured ferromagnetic alloys with specific crystallographic orientations to achieve high magnetic anisotropic energy density. This allows micropatterning to proceed while maintaining manageable magnetization reversal fields through optimized magnetic parameters
Solution Approach 2:
The patent employs composite magnetic layer structures including L10 structured ferromagnetic alloys (such as CoPt, FePt), nitride underlying layers with NaCl structure, and nonmagnetic spacer layers. These composite materials provide both the necessary magnetic anisotropy for thermal stability and controlled magnetization reversal characteristics
2Reliability
If magnetic anisotropic energy density is increased to improve thermal disturbance resistance, then reliability is improved, but the magnetic field required for magnetization reversal increases
Solution Approach 1:
The patent optimizes the balance between magnetic anisotropic energy density and magnetization reversal field by using perpendicular magnetization arrangement with L10 structured alloys. The specific crystallographic orientation ((001) plane) and composition ratios are tuned to achieve high thermal stability while maintaining reasonable switching fields
Solution Approach 2:
The patent replaces magnetic field-based magnetization reversal with spin-polarized current injection. This substitution allows high thermal stability to be achieved without proportionally increasing the magnetic field requirement, as the switching mechanism transitions to a spin-transfer torque mechanism
3Use of energy by moving object
If spin-polarized current method is used to reduce current requirements, then energy consumption is reduced, but thermal disturbance resistance becomes problematic with micropatterning
Solution Approach 1:
The patent changes the magnetic layer parameters by using perpendicular magnetization arrangement with L10 structured alloys, which increases magnetic anisotropic energy density. This allows the spin-polarized current method to remain effective while achieving sufficient thermal disturbance resistance even at micropatterned dimensions
Solution Approach 2:
The patent introduces nitride underlying layers with NaCl structure as intermediaries that provide both structural support and magnetic anisotropy enhancement. These layers mediate between the spin-polarized current injection and the magnetic layer, enabling efficient spin transfer while maintaining high thermal stability
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 allows for reduced current requirements for magnetization reversal, improved thermal disturbance resistance, and a high magnetoresistive ratio, enabling more efficient and compact MRAM designs.
Implementation Method 1
a first magnetic layer provided on the first underlying layer, having magnetic anisotropy perpendicular to a film surface
Implementation Method 2
magnetization reversal caused by a spin-polarized current has been theoretically predicted and experimentally confirmed
Implementation Method 3
The GMR (Giant Magnetoresistive) effect or TMR (Tunneling Magnetoresistive) effect is applied to a magnetic head of the HDD. Both the GMR effect and TMR effect detect a magnetic field from a magnetic medium by using a resistance change caused by an angle the magnetization directions in two magnetic layers make with each other.
Implementation Method 4
The GMR (Giant Magnetoresistive) effect or TMR (Tunneling Magnetoresistive) effect is applied to a magnetic head of the HDD
Data Source
AI summary
A magnetoresistive element includes a first underlying layer having an NaCl structure and containing a nitride orienting in a (001) plane, a first magnetic layer provided on the first underlying layer, having magnetic anisotropy perpendicular to a film surface, having an L10 structure, and containing a ferromagnetic alloy orienting in a (001) plane, a first nonmagnetic layer provided on the first magnetic layer, and a second magnetic layer provided on the first nonmagnetic layer and having magnetic anisotropy perpendicular to a film surface.