Tunneling Magnetic Sensor Platinum Layer VCR Reduction
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Solution Overview
Problem
Tunneling magnetic sensors with titanium oxide insulating barrier layers exhibit high absolute values of voltage coefficient of resistance (VCR), leading to unstable operation and difficulty in achieving high resistance change rates at low RA, which affects data transmission and output.
Innovation Solution
Incorporating a platinum layer between the insulating barrier layer and the magnetic layers, with a thickness of 0 to 4 Å, and using titanium magnesium oxide (Ti—Mg—O) instead of titanium oxide for the insulating barrier layer, along with a soft magnetic layer and enhancement layer structure, to reduce VCR and enhance resistance change rate (ΔR/R) at low RA.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If titanium oxide (Ti—O) is used for the insulating barrier layer, then the resistance change rate (ΔR/R) is enhanced, but the absolute value of VCR (voltage coefficient of resistance) extremely increases, resulting in unstable operation
Solution Approach 1:
A platinum layer is introduced as an intermediary between the Ti—O insulating barrier layer and the magnetic layers. This platinum intermediary layer modifies the tunneling characteristics and reduces the absolute value of VCR while preserving the high resistance change rate provided by the Ti—O barrier, thereby resolving the contradiction between enhanced sensitivity and operational stability.
Solution Approach 2:
The patent employs a composite structure combining Ti—O insulating barrier layer with platinum layers and magnetic layers. This composite material approach allows the Ti—O to provide high resistance change rate while the platinum components suppress excessive VCR, achieving both high sensitivity and stable operation simultaneously.
2Reliability
If the insulating barrier layer is formed of aluminum oxide, then the absolute value of VCR is reduced, but the resistance change rate (ΔR/R) cannot be enhanced as effectively as with titanium oxide
Solution Approach 1:
The patent changes the material parameter of the insulating barrier layer from aluminum oxide to titanium oxide, which inherently provides a higher resistance change rate. The platinum layer addition then adjusts the VCR parameter back to acceptable levels, allowing simultaneous achievement of high resistance change rate and operational stability.
3Power
If high RA (sensor resistance × sensor area) is used, then the sensor output is increased, but high-speed data transmission becomes difficult
Solution Approach 1:
The platinum layer modification changes the electrical resistance characteristics of the tunneling magnetic sensor, enabling optimization of the RA parameter. This allows the sensor to achieve high-speed data transmission capability while maintaining sufficient output signal level through adjusted resistance properties.
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 effectively reduces the absolute value of VCR, stabilizes sensor operation, and increases the resistance change rate (ΔR/R) at low RA, improving data transmission and output stability.
Implementation Method 1
A tunneling magnetic sensor (tunneling magnetoresistive element), which utilizes a tunneling effect to cause a resistance change
Implementation Method 2
This tunneling magnetic sensor can achieve a lower absolute value of VCR than known tunneling magnetic sensors to suppress variations in sensor resistance with voltage change
Implementation Method 3
The free magnetic layer includes a soft magnetic layer and an enhancement layer disposed between the soft magnetic layer and the insulating barrier layer
Data Source
AI summary
A tunneling magnetic sensor includes a platinum layer between a pinned magnetic layer and an insulating barrier layer. The platinum layer can probably vary the barrier height (potential height) and barrier width (potential width) of the insulating barrier layer to reduce the absolute value of VCR, thus providing higher operating stability than known tunneling magnetic sensors. In addition, the insulating barrier layer can achieve increased flatness at its bottom interface (where the insulating barrier layer starts to be formed). The tunneling magnetic sensor can therefore provide a higher rate of resistance change (ΔR/R) at low RA than known tunneling magnetic sensors.