Fluoride Tunnel Barrier in Magnetoresistive Elements for High PMA
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Solution Overview
Problem
Current magnetoresistive elements face challenges in achieving high perpendicular magnetic anisotropy and high Tunnel MagnetoResistance (TMR) ratio, which are crucial for advanced magnetic memory and sensor applications, particularly in securing large-capacity magnetic memory and wide magnetic field detection.
Innovation Solution
Incorporating a fluoride insulator into the nonmagnetic layer of the magnetoresistive element, which enhances perpendicular magnetic anisotropy and maintains a high TMR ratio by optimizing the interface between magnetic and nonmagnetic layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cobalt iron (CoFe) alloy is used for the magnetic layer and magnesium oxide (MgO) for the nonmagnetic layer, then the TMR effect is achieved, but perpendicular magnetic anisotropy suitable for ultra-Gbit class large-capacity magnetic memory cannot be secured
Solution Approach 1:
The patent uses a composite structure consisting of a CoFeB magnetic layer combined with a MgAlO3 nonmagnetic layer. This composite material approach allows achieving both high perpendicular magnetic anisotropy and high TMR ratio, overcoming the limitations of conventional CoFe/MgO structures. The specific combination of CoFeB (0.8 nm thick) and MgAlO3 (0.3 nm thick) creates synergistic effects that enable ultra-Gbit class magnetic memory performance.
2Reliability
If the film thickness of the nonmagnetic thin film is reduced to several nm to achieve TMR effect, then tunnel current flows and magnetization detection is enabled, but perpendicular magnetic anisotropy becomes difficult to maintain
Solution Approach 1:
The patent optimizes the thickness parameters of both the magnetic layer and nonmagnetic layer to achieve the desired performance. Specifically, the CoFeB layer is set at 0.8 nm and the MgAlO3 layer at 0.3 nm. These precise parameter adjustments enable the system to maintain perpendicular magnetic anisotropy while preserving the TMR effect, allowing the thin film structure to function effectively for magnetization detection.
3Measurement precision
If a perpendicular magnetization film is used for the magnetic field detection layer to enable wide magnetic field region detection, then detection capability is improved, but large perpendicular magnetic anisotropy must be secured which is difficult with conventional materials
Solution Approach 1:
The patent employs a composite structure of CoFeB magnetic layer and MgAlO3 nonmagnetic layer to achieve both wide magnetic field detection capability and large perpendicular magnetic anisotropy. The CoFeB material provides high magnetization saturation and the MgAlO3 layer contributes to strong perpendicular magnetic anisotropy through interface effects, enabling the detection layer to respond to a wide range of magnetic field intensities while maintaining stable perpendicular magnetization orientation.
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 provides high thermal stability and improved magnetic field detection capabilities, reducing operation errors and increasing the operational margin for magnetic devices.
Implementation Method 1
Incorporating a fluoride insulator into the nonmagnetic layer of the magnetoresistive element, which enhances perpendicular magnetic anisotropy
Implementation Method 2
magnitude of the tunnel current depends on a relative angle of magnetization of the two magnetic layers. This is called a tunnel magneto resistance (TMR) effect
Data Source
AI summary
A magnetoresistive element according to the present embodiment includes a first magnetic layer (11) stacked on a base layer (10), a second magnetic layer (13), and a first nonmagnetic layer (12) arranged between the first magnetic layer (11) and the second magnetic layer (13). The first nonmagnetic layer (12) includes an insulating material including fluorine.