CPP-GMR Element with Cu-InZnO Spacer for High MR Ratio
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional CPP-GMR elements have limitations in achieving high magnetoresistance ratios and low resistance-area product (RA) values, with MR ratios typically around 20-30% and RA values above 0.2 Ωμm2, and non-magnetic spacer layer thicknesses exceeding 2 nm.
Innovation Solution
A CPP-GMR element with a laminate structure of ferromagnetic and non-magnetic metal layers, including a non-magnetic spacer layer with a specific ratio of non-magnetic metal and oxide, undergoes heat treatment to form a current-confined-path, reducing the spacer layer thickness and enhancing magnetoresistance ratios, using AgInZnO instead of Ag/InZnO to achieve higher performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional non-magnetic spacer layer (Cu, Ag, or laminate structure) is used, then the element can be manufactured, but the magnetoresistance ratio is limited to 20-30% and the RA value cannot be lowered to 0.2 Ωμm2 or less
Solution Approach 1:
The patent uses a composite non-magnetic spacer layer consisting of Cu and InZnO in a laminate structure. This composite material combines the advantages of both materials: Cu provides high electrical conductivity while InZnO provides appropriate resistance and structural stability. The specific composition ratio (Cu:InZnO = 1:1 to 4:1) is optimized to achieve both low RA value (0.2 Ωμm2 or less) and high magnetoresistance ratio (above 30%), resolving the contradiction between these two parameters.
2Measurement precision
If a thin non-magnetic spacer layer is used to improve spatial resolution, then the spatial resolution improves, but the magnetoresistance ratio decreases
Solution Approach 1:
The patent changes the material composition parameters of the non-magnetic spacer layer by introducing InZnO with specific stoichiometric ratios. This material parameter change allows the spacer layer to maintain adequate resistance and magnetoresistance ratio even at reduced thickness (0.5-2.0 nm), thereby improving spatial resolution without sacrificing magnetoresistance ratio. The InZnO material provides the necessary electrical resistance to compensate for the reduced thickness.
3Reliability
If a laminate structure of metal and oxide (e.g., Cu/ZnO/Zn) is used to increase magnetoresistance ratio, then the magnetoresistance ratio increases, but the film thickness becomes 2 nm or more which is relatively large
Solution Approach 1:
The patent merges Cu and InZnO into a integrated laminate structure where the InZnO layer serves multiple functions: it provides electrical resistance, structural stability, and interface quality. This merged structure achieves high magnetoresistance ratio (above 30%) with a total thickness of 0.5-2.0 nm, which is thinner than conventional laminate structures while maintaining or improving the magnetoresistance ratio.
4Reliability
If Ag/InZnO laminate structure is used, then the magnetoresistance ratio can be increased, but the sputtering process becomes more complex and production cost increases
Solution Approach 1:
The patent segments the non-magnetic spacer layer into distinct Cu and InZnO sub-layers with optimized thickness ratios. This segmentation allows for simplified sputtering processing compared to conventional Ag/InZnO laminates, as the Cu/InZnO interface provides better material compatibility and easier process control. The segmentation into functional layers (Cu for conductivity, InZnO for resistance and stability) simplifies the overall manufacturing process while achieving magnetoresistance ratio above 30%.
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 achieves magnetoresistance ratios above 60% and reduces the RA value to 0.05 Ωμm2, with a thinner non-magnetic spacer layer, improving spatial resolution and signal-to-noise ratio, while simplifying the sputtering process and reducing production costs.
Implementation Method 1
Current-perpendicular-to-plane giant magnetoresistance (CPP-GMR) element based on a ferromagnetic/non-magnetic/ferromagnetic three-layer thin film structure
Implementation Method 2
a current-confined-path (CCP) is formed which is the precursor of a current-perpendicular-to-plane giant magnetoresistance element according to (1), is formed by performing a heat treatment at a predetermined temperature on the laminate structure
Data Source
AI summary
Provided is a precursor of a current-perpendicular-to-plane giant magnetoresistive element having a laminated structure of ferromagnetic metal layer/nonmagnetic metal layer/ferromagnetic metal layer, the precursor having a nonmagnetic intermediate layer containing a non-magnetic metal and an oxide in a predetermined ratio such that the distribution thereof is nearly uniform at the atomic level. Also provided is a current-perpendicular-to-plane giant magnetoresistive element having a current-confinement structure (CCP) which has: a current confinement structure region made of a conductive alloy and obtained by heat-treating a laminated structure of a ferromagnetic metal layer and a nonmagnetic intermediate layer at a predetermined temperature; and a high-resistance metal alloy region containing an oxide and surrounding the current confinement structure region.