2D Magnetoresistive Sensor Reference Layer for Low High-Field Error
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing magnetoresistive sensor elements for 2D magnetic field detection suffer from high angular errors at high magnetic fields due to low stiffness of the synthetic antiferromagnetic (SAF) structure, which also compromises the magneto-transport properties and TMR response.
Innovation Solution
The magnetoresistive element incorporates a ferromagnetic reference layer with a synthetic antiferromagnetic (SAF) structure, including a reference coupling layer between a reference pinned layer and a reference coupled layer, with a thin transition metal insert layer between the second and third coupled sublayers, enhancing the SAF stiffness and TMR response without reducing magnetic layer thicknesses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the thicknesses of the first and second ferromagnetic reference layers are decreased to increase SAF structure stiffness, then the saturation field Hsat increases and magnetization stability improves, but the TMR response becomes very low and pinning with the AF layer is lost
Solution Approach 1:
The invention changes the material composition parameter by introducing a transition metal element (Ta, W, Mo, Hf, Mg, or Al) into the reference coupled layer, forming a ferromagnetic alloy layer. This material parameter change allows the layer to maintain adequate thickness (1-5 nm) while achieving the required SAF structure stiffness and high saturation field, thereby preserving both magnetization stability and TMR response without the need to decrease layer thickness
Solution Approach 2:
The invention creates a composite ferromagnetic layer by combining a CoFeB-based ferromagnetic material with a transition metal element (Ta, W, Mo, Hf, Mg, or Al). This composite structure integrates the high spin polarization of CoFeB with the enhanced stiffness contribution from the transition metal, achieving both high TMR response and high saturation field simultaneously while maintaining adequate layer thickness
2Stability of the object's composition
If the thicknesses of the first and second ferromagnetic reference layers are decreased to increase SAF structure stiffness, then the saturation field Hsat increases, but the magneto-transport properties deteriorate
Solution Approach 1:
The invention changes the material composition parameter by incorporating a transition metal element (Ta, W, Mo, Hf, Mg, or Al) at 1-20 at.% concentration in the reference coupled layer. This compositional parameter change enhances the SAF structure stiffness and saturation field while maintaining the layer thickness at 1-5 nm, thereby preserving magneto-transport properties without compromising structural stiffness
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 achieves high saturation field, improved thermal stability, and reduced angular errors even at high magnetic fields, while maintaining high TMR response and magnetic properties.
Implementation Method 1
A magnetic sensor element based on the tunnel magnetoresistance (TMR) effect can be used for 2D magnetic field detection
Implementation Method 2
a pinned first ferromagnetic reference layer in contact with an antiferromagnetic layer
Data Source
AI summary
A magnetoresistive element for a two-dimensional magnetic field sensor, including: a ferromagnetic reference layer having a fixed reference magnetization, a ferromagnetic sense layer having a sense magnetization that can be freely oriented relative to the reference magnetization in the presence of an external magnetic field, and a tunnel barrier layer between the reference and sense ferromagnetic layers; the reference layer including a reference coupling layer between a reference pinned layer and a reference coupled layer; the reference coupled layer including a first coupled sublayer in contact with the reference coupling layer, a second coupled sublayer, a third coupled sublayer and a insert layer between the second and third coupled sublayers; the insert layer comprising a transition metal and has a thickness between about 0.1 and about 0.5 nm, and the thickness of the reference coupled layer is between about 1 nm and about 5 nm.