CPP Magnetoresistive Element with Composite Spacer Layer
Solution Overview
Problem
Current magnetoresistive elements, such as CPP-GMR and TMR elements, face challenges in achieving appropriate resistance values and high magnetoresistance change ratios, which affect the performance of magnetic recording devices in terms of data transfer rate and high-frequency response.
Innovation Solution
A magnetoresistive element is designed with a spacer layer comprising a nonmagnetic metal layer, a Ga oxide semiconductor layer, and a Zn oxide semiconductor layer, stacked in a specific order, to optimize the resistance and magnetoresistance change ratio, while preventing oxidation of ferromagnetic layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a nonmagnetic conductive layer is used as the spacer layer in a CPP-GMR element, then the heat dissipation efficiency is improved and operating current can be increased, but the magnetoresistance change amount becomes small due to low resistance
Solution Approach 1:
The spacer layer is constructed as a composite structure with a nonmagnetic conductive layer (Cu) and an oxide semiconductor layer (In2O3), combining the advantages of both materials: the Cu layer provides excellent heat dissipation and electrical conductivity, while the In2O3 layer provides high resistance and high magnetoresistance change ratio, achieving both improved heat dissipation efficiency and high reliability
Solution Approach 2:
By changing the resistance parameter of the spacer layer through material composition control (combining conductive Cu with high-resistance In2O3), the invention achieves optimal balance between heat dissipation and magnetoresistance performance, resolving the contradiction between low resistance (good for heat dissipation) and high resistance (good for magnetoresistance change ratio)
2Length of moving object
If the width of the MR element is reduced to reduce track width, then the track width is reduced, but the top and bottom surfaces of the MR element are reduced in area leading to poor heat dissipation
Solution Approach 1:
The composite spacer layer structure with highly conductive Cu provides superior heat dissipation capability, compensating for the reduced surface area caused by narrower track width, thereby maintaining effective heat dissipation even as the element dimensions are reduced for higher recording density
3Quantity of substance
If an insulating layer is used as the spacer layer in a TMR element, then the resistance is high which is suitable for reducing track width, but the magnetoresistance change ratio is limited
Solution Approach 1:
The oxide semiconductor layer (In2O3) in the composite spacer layer provides high resistance similar to insulating layers, enabling track width reduction, while the specific properties of the oxide semiconductor material achieve a high magnetoresistance change ratio, overcoming the limitation of conventional insulating layers
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 appropriate resistance values and high magnetoresistance change ratios, enhancing the performance of magnetic recording devices by improving data transfer rates and high-frequency response.
Implementation Method 1
a spacer layer that is disposed between the first ferromagnetic layer and the second ferromagnetic layer, wherein the spacer layer includes a nonmagnetic metal layer, a Ga oxide semiconductor layer, and a Zn oxide semiconductor layer that are stacked in this order
Implementation Method 2
the nonmagnetic metal layer has a function of preventing oxidation of one of the ferromagnetic layers that is in contact with the spacer layer
Data Source
AI summary
An MR element includes a first ferromagnetic layer, a second ferromagnetic layer, and a spacer layer disposed between the first and second ferromagnetic layers. The spacer layer includes a nonmagnetic metal layer, a first oxide semiconductor layer, and a second oxide semiconductor layer that are stacked in this order. The nonmagnetic metal layer is made of Cu, and has a thickness in the range of 0.3 to 1.5 nm. The first oxide semiconductor layer is made of a Ga oxide semiconductor, and has a thickness in the range of 0.5 to 2.0 nm. The second oxide semiconductor layer is made of a Zn oxide semiconductor, and has a thickness in the range of 0.1 to 1.0 nm.