Exchange-Coupled Film with IrMn-PtCr Stack for Magnetic Field Resistance
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Solution Overview
Problem
Magnetic sensing devices face challenges in maintaining strong-magnetic field resistance, especially when exposed to high magnetic fields, as existing exchange-coupled films are not adequately resistant to reversing the magnetization direction of pinned magnetic layers.
Innovation Solution
An exchange-coupled film structure is developed, comprising an antiferromagnetic layer with a stack of IrMn, PtMn, PtCr, and another PtMn layer, which enhances the exchange coupling field, providing excellent strong-magnetic field resistance while reducing the overall thickness of the antiferromagnetic layer for improved production efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional antiferromagnetic films (CoMn, NiMn, PtMn, PtCr) are used in exchange-coupled structures, then the device can be manufactured with existing processes, but the exchange coupling field Hex is insufficient and strong-magnetic field resistance is poor
Solution Approach 1:
The patent employs a composite antiferromagnetic layer structure consisting of IrMn, PtMn, and PtCr layers stacked together. This composite structure combines the high exchange coupling field capability of IrMn with the beneficial properties of PtMn and PtCr, achieving superior strong-magnetic field resistance while maintaining compatibility with existing manufacturing processes
Solution Approach 2:
The patent applies local quality by positioning specific materials at specific locations within the antiferromagnetic layer. The IrMn layer is placed adjacent to the pinned magnetic layer to maximize exchange coupling, while PtMn and PtCr layers are positioned to provide structural stability and additional magnetic properties, optimizing performance at each interface
2Reliability
If the thickness of the PtCr layer is increased to improve exchange coupling, then Hex increases, but the total thickness of the antiferromagnetic layer increases reducing production efficiency
Solution Approach 1:
The patent segments the antiferromagnetic layer into multiple functional sub-layers (IrMn, PtMn, PtCr) rather than using a single thick layer. Each segment contributes differently to the exchange coupling, allowing the system to achieve high Hex with a more distributed and optimized thickness distribution that improves production efficiency
Solution Approach 2:
The patent optimizes the thickness parameters of each individual layer within the composite structure. By carefully controlling the thickness of IrMn, PtMn, and PtCr layers separately, the system achieves maximum exchange coupling field Hex while keeping the total thickness optimized for production efficiency
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 enhanced exchange coupling field ensures that the magnetization direction of the pinned magnetic layer is not easily reversed, even in strong external magnetic fields, thereby improving the device's resistance and operational stability.
Implementation Method 1
an exchange-coupled film includes an antiferromagnetic layer and a ferromagnetic layer stacked together, the antiferromagnetic layer having a structure including an IrMn layer, a first PtMn layer, a PtCr layer, and a second PtMn layer stacked in that order
Implementation Method 2
the IrMn layer, which is close to the ferromagnetic layer... the exchange coupling field Hex is high, and the relationship between the exchange coupling field Hex and the coercive force Hc is prone to be Hex>Hc
Data Source
AI summary
An exchange-coupled film includes a antiferromagnetic layer and a pinned magnetic layer including a ferromagnetic layer stacked together, the antiferromagnetic layer having a structure including an IrMn layer, a first PtMn layer, a PtCr layer, and a second PtMn layer stacked in that order, the IrMn layer being in contact with the pinned magnetic layer. The second PtMn layer preferably has a thickness of more than 0 Å and less than 60 Å, in some cases. The PtCr layer preferably has a thickness of 100 Å or more, in some cases. The antiferromagnetic layer preferably has a total thickness of 200 Å or less, in some cases.