Tunnel junction magnetoresistance sensor having adjustable measurement range and preparation method thereof

Abstract

The invention relates to a tunnel junction magnetoresistance sensor having an adjustable measurement range and a preparation method thereof. The tunnel junction magnetoresistance sensor comprises a substrate, insulation layers, magnetoresistance conductive layers and a magnetoresistance structure, wherein the magnetoresistance structure is arranged on an upper surface of the substrate, the insulation layers are arranged on the substrate at two sides of the magnetoresistance structure, the magnetoresistance conductive layers are arranged on upper surfaces of the magnetoresistance structure andthe insulation layers, the substrate comprises a substrate bottom electrode, a piezoelectric material and a substrate top electrode, the substrate bottom electrode and the substrate top electrode arerespectively arranged on a lower surface and an upper surface of the piezoelectric material, the magnetoresistance structure comprises a buffer layer, a pinning layer and a magnetic tunnel junction layer, two buffer layers are arranged on the upper surface of the substrate in a lamination way, the magnetic tunnel junction layer and the pinning layer are sequentially arranged between the two bufferlayers from top to bottom, the magnetic tunnel junction layer is a layered structure comprising a pinned layer, a barrier layer and a free layer, and the pinned layer is arranged on an upper surfaceof the pinning layer. With the adoption of an electric field control effect of a magnetic anisotropy field in a magnetoelectric composite material, the adjustment of a magnetism direction of the freelayer in the magnetic tunnel junction by an electric field is achieved, and the tunnel junction magnetoresistance sensor has the characteristics of high efficiency, small size and low energy consumption and is easy to integrate.

Description

technical field [0001] The invention belongs to the technical field of sensors, in particular to a tunnel junction magnetoresistance sensor with an adjustable measuring range and a preparation method thereof. Background technique [0002] With the development of the information society, especially the advent of the Internet of Things era, emerging industries such as smart home appliances, new energy vehicles, and robots have an increasing demand for high-sensitivity miniature magnetic sensors. The low-frequency magnetic noise index of superconducting quantum interferometer magnetometer, electron spin magnetometer, fluxgate meter, proton magnetometer, magnetoelectric block sensor and other types of magnetic sensors can reach pT / Hz 1 / 2 Even fT / Hz 1 / 2 magnitude, however its volume is generally greater than 10 2 ~10 3 mm 3 . In contrast, the size of the Hall sensor, which currently accounts for 70% of the magnetic sensor market, can be reduced by several orders of magnitu...

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Problems solved by technology

It can be seen that the linear measurement range of the tunnel junction magnetoresistive sensor is limited by the coercive field of the free layer. Generally, a soft magnetic alloy is used as the free layer, and its linear measurement range is between -20 and 20Oe, which seriously affects the application of the magnetoresistance sensor. scope

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