Magnetoresistance Element Barber-Pole Electrode Angle Optimization
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Solution Overview
Problem
Existing magnetoresistance effect elements face challenges in downsizing due to the need for a bias magnetic field and suboptimal configuration of barber-pole electrodes, which affects sensitivity and linearity in power measurement applications.
Innovation Solution
The magnetoresistance effect element features a strip-shaped magnetic film with barber-pole electrodes having an inclined angle within ±5° of a calculated value, optimizing the angle between the magnetization easy axis and current vector to achieve superior linearity and sensitivity without requiring a separate bias magnetic field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If barber-pole electrodes are configured at 45 degrees to the longitudinal direction of the magnetic film, then the magnetoresistance effect element can operate without an external bias magnetic field, but the sensitivity and linearity are suboptimal due to material conductivity differences causing current vector deviation
Solution Approach 1:
The patent changes the geometric parameter of the barber-pole electrode configuration from the conventional 45 degrees to a specific angle range (30-40 degrees or 40-45 degrees depending on the embodiment). This parameter adjustment compensates for the current vector deviation caused by conductivity differences between the electrode and magnetic film materials, thereby optimizing both linearity and sensitivity while maintaining operation without external bias magnetic field
Solution Approach 2:
The patent applies preliminary anti-action by pre-compensating for the expected current vector deviation through optimized electrode angle design. The electrode angle is calculated in advance to counteract the refraction effect, ensuring that the net current vector in the magnetic film achieves the desired 45-degree orientation relative to the magnetization easy axis, thus achieving optimal magnetoresistance effect linearity
2Measurement precision
If the inclined angle of barber-pole electrodes is optimized to improve sensitivity and linearity, then measurement precision improves, but manufacturing precision requirements increase
Solution Approach 1:
The patent provides specific angle ranges (30-40 degrees or 40-45 degrees) that balance measurement precision with manufacturing feasibility. These ranges are derived from theoretical optimization considering material conductivity ratios, providing a practical target for manufacturing while ensuring optimal performance
Solution Approach 2:
The patent establishes a relationship between electrode angle, material conductivity, and performance metrics that can serve as feedback for manufacturing process control. By understanding the quantitative relationship between angle deviation and performance degradation, manufacturers can implement appropriate tolerance controls and compensation measures
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 enhances the magnetoresistance effect element's sensitivity and operating range, allowing for more effective power measurement with improved linearity and reduced size, suitable for small ammeter and power meter applications.
Implementation Method 1
The magnetoresistance effect is a phenomenon that an electric resistance varies depending on a magnetic field applied from outside. This phenomenon occurs by variation of a direction of a current flowing in a magnetic film and a magnetization direction formed in the magnetic film.
Implementation Method 2
when current I2 flows between connection electrodes 116a and 116b at both sides of the magnetoresistance effect element 100, current flows from one inclined side 114p to another inclined side 114p. Then, the current I2 flows in a direction different from the longitudinal direction (magnetization direction of the magnetic film 112) of the stripe-shaped magnetic film 112
Data Source
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AI summary
When miniaturizing an ammeter or wattmeter, a magnetoresistance effect element given a barber-pole electrode could be considered an efficient device. It was considered that a barber-pole electrode formed at 45° with respect to an axis of easy magnetization (the longitudinal direction of a rectangular-shaped element) would be the most efficient. Current is refracted, however, when the current passes through the boundaries of substances with different conductivity, so a barber-pole electrode formed at 45° is not the most efficient. According to the invention, it is possible to provide a highly efficient magnetoresistance element having a rectangular magnetic film whereupon an axis of easy magnification is induced in the longitudinal direction, and a barber-pole electrode which is formed upon the magnetic film at an oblique angle θ to the longitudinal direction, where the magnetoresistance element takes into account current refraction at the boundary between the electrode and the magnetic film.