Thin-film magnetic sensor with groove structures

Abstract

A thin-film magnetic sensor with groove structures is characterized by comprising two rectangular magnetic films and a rectangular spiral coil arranged between the two rectangular magnetic films, wherein the rectangular spiral coil adopts an overall planar spiral structure, and is spirally wound out from a certain position of the rectangular interior in the clockwise or anticlockwise direction; aplurality of rectangular grooves are formed on the inner surface of each rectangular magnetic film and are perpendicular to the sensing direction of the rectangular magnetic film (namely the directionof a magnetic field to be tested, which is usually the length direction of the thin film), and the number of the rectangular grooves is the same as the number of the turns of the rectangular spiral coil; and the rectangular grooves of one rectangular magnetic film are opposite to the rectangular grooves of the other rectangular magnetic film, so that conductors in the rectangular spiral coil, which are perpendicular to the sensing direction, are embedded in the rectangular magnetic films. The thin-film magnetic sensor with the groove structures provided by the invention has the advantage thatthe thin-film magnetic sensor is more sensitive to an external magnetic field.

Description

technical field [0001] The invention relates to a sensor, especially a thin-film magnetic sensor with a groove structure. Background technique [0002] Magnetic sensors are one of the most widely used sensors, and can directly or indirectly measure many physical, chemical, biological and other parameters through magnetic field measurement. The planar spiral coil and the soft magnetic film made of high magnetic permeability soft magnetic material can be combined to form a magnetic sensor with a thin film coil structure. [0003] The sensing process of the external magnetic field of the thin film magnetic sensor can be divided into two stages: [0004] In the first stage, in the thin film coil, the effective magnetic permeability of the soft magnetic film μ eff External magnetic field H app the response to: [0005] According to the magnetic properties (magnetization curve) of the soft magnetic material, in the process of magnetization, the effective permeability μ of the ...

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Problems solved by technology

Therefore, according to formula (3), even if the magnetic permeability μ of the magnetic material itself r Very large, when it is made into a sample of a specific shape (such as a film shape), the demagnetization field H d will also make the actual permeability μ of the sample eff The size and degree of change are limited, and the maximum change range is only 1 / N d

This greatly reduces the sensitivity of the magnetic film to external magnetic fields, which in turn reduces the sensitivity of the sensor

Demagnetizing field H d The size of the magnetic film is closely related to the shape and structure of the magnetic film. The traditional improvement method is to change the microscopic composition of the soft magnetic material selected for the magnetic film or to reduce the size of the magnetic film by changing the size of the magnetic film (such as increasing the aspect ratio, reducing the overall thickness, etc.) Small demagnetizing field H d However, under the premise of a given soft magnetic material, it is impossible to adjust the particle type or the content of each component selected by the material, but relying on adjusting the external size of the film, although the demagnetization factor N can be reduced d , to increase the effective permeability μ of the film eff , but this change in the overall size will affect the inductance value of the thin film coil, and ultimately affect the sensitivity performance of the sensor

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