阅读说明：本技术 一种高灵敏磁隧道结温度探测器 (High-sensitivity magnetic tunnel junction temperature detector ) 是由 于孟今 于 2021-08-31 设计创作，主要内容包括：本发明涉及温度探测领域,具体提供了一种高灵敏磁隧道结温度探测器,钉扎层置于反铁磁层上,势垒层置于钉扎层上,自由层置于势垒层上,自由层中设有孔洞,热膨胀材料填充满孔洞,贵金属层置于自由层上,热膨胀材料与贵金属层接触。在本发明中,钉扎层、势垒层、自由层形成磁隧道结。应用时,将本发明置于待测环境中；同时应用磁场作用于本发明。贵金属层从环境吸收热量,改变了磁隧道结的磁电阻；通过测量在待测环境中,磁隧道结的磁电阻的变化,确定待测环境的温度。本发明具有温度探测灵敏度高的优点。另外,本发明是基于传统电学的,设备简单,温度探测灵敏度高。(The invention relates to the field of temperature detection, and particularly provides a high-sensitivity magnetic tunnel junction temperature detector. In the invention, the pinning layer, the barrier layer and the free layer form a magnetic tunnel junction. When in application, the invention is placed in an environment to be tested; while applying a magnetic field to the invention. The noble metal layer absorbs heat from the environment, and the magnetoresistance of the magnetic tunnel junction is changed; and determining the temperature of the environment to be measured by measuring the change of the magnetoresistance of the magnetic tunnel junction in the environment to be measured. The invention has the advantage of high temperature detection sensitivity. In addition, the invention is based on the traditional electricity, has simple equipment and high temperature detection sensitivity.)

1. The high-sensitivity magnetic tunnel junction temperature detector is characterized by comprising an antiferromagnetic layer, a pinning layer, a barrier layer, a free layer, a thermal expansion material and a noble metal layer, wherein the antiferromagnetic layer is made of a hard magnetic antiferromagnetic material, the pinning layer is arranged on the antiferromagnetic layer, the pinning layer is made of a metal or a semi-metal with high spin polarizability, the barrier layer is arranged on the pinning layer, the free layer is arranged on the barrier layer, the free layer is made of a soft magnetic material with weak magnetic anisotropy, a hole is formed in the free layer, the thermal expansion material is filled in the hole, the noble metal layer is arranged on the free layer, and the thermal expansion material is in contact with the noble metal layer.

2. The high sensitivity magnetic tunnel junction temperature detector of claim 1, wherein: the holes are arranged periodically.

3. The high sensitivity magnetic tunnel junction temperature detector of claim 2, wherein: the arrangement period of the holes is square or rectangular.

4. The high sensitivity magnetic tunnel junction temperature detector of claim 3, wherein: the bottom of the hole is thick; the top of the hole is thin.

5. The high sensitivity magnetic tunnel junction temperature detector of claim 4, wherein: the piezoelectric material particles are arranged in the thermal expansion material in the holes.

6. The high sensitivity magnetic tunnel junction temperature detector of claim 5, wherein: the grains of piezoelectric material are disposed on a surface of the barrier layer.

7. The highly sensitive magnetic tunnel junction temperature detector of any of claims 1-6, wherein: the barrier layer is made of aluminum oxide or magnesium oxide.

8. The high sensitivity magnetic tunnel junction temperature detector of claim 7, wherein: the free layer is made of NiFe alloy, CoFe alloy and CoFeB alloy.

9. The high sensitivity magnetic tunnel junction temperature detector of claim 8, wherein: the pinning layer is made of Co, Fe, CoFe, CoFeB and CoFeAl alloy.

10. The high sensitivity magnetic tunnel junction temperature detector of claim 9, wherein: the material of the antiferromagnetic layer is IrMn, PtMn and FeMn.

Technical Field

The invention relates to the field of temperature detection, in particular to a high-sensitivity magnetic tunnel junction temperature detector.

Background

Temperature is an important information and an important basic physical quantity of an object. The temperature is closely connected with our daily life, and is closely related with physical processes in a low-temperature environment. Although the sensitivity of the optical fiber temperature sensor is higher than that of the common resistance type temperature sensor. However, the fiber optic temperature sensor still cannot meet the requirement of high-sensitivity detection of temperature in a low-temperature environment. The temperature detection technology based on a new principle is explored, and high-sensitivity temperature detection can be realized on the basis of simple devices.

Disclosure of Invention

In order to solve the problems, the invention provides a temperature detector based on a high-sensitivity magnetic tunnel junction, which comprises an antiferromagnetic layer, a pinning layer, a barrier layer, a free layer, a thermal expansion material and a noble metal layer, wherein the antiferromagnetic layer is made of a hard magnetic antiferromagnetic material, the pinning layer is arranged on the antiferromagnetic layer, the pinning layer is made of metal or semimetal with high spin polarizability, the barrier layer is arranged on the pinning layer, the free layer is arranged on the barrier layer, the free layer is made of a soft magnetic material with weak magnetic anisotropy, holes are formed in the free layer, the thermal expansion material is filled in the holes, the noble metal layer is arranged on the free layer, and the thermal expansion material is in contact with the noble metal layer.

Further, the holes are arranged periodically.

Further, the period of the hole arrangement is square or rectangular.

Furthermore, the bottom of the hole is thick; the top of the hole is thin.

Still further, the piezoelectric material particles are included, and the piezoelectric material particles are disposed in the thermally expansive material in the holes.

Further, grains of piezoelectric material are disposed on a surface of the barrier layer.

Further, the material of the barrier layer is aluminum oxide or magnesium oxide.

Further, the material of the free layer is NiFe alloy, CoFe alloy, CoFeB alloy.

Further, the material of the pinning layer is Co, Fe, CoFe, CoFeB, CoFeAl alloy.

Further, the material of the antiferromagnetic layer is IrMn, PtMn, FeMn.

The invention has the beneficial effects that: the invention provides a high-sensitivity magnetic tunnel junction temperature detector which comprises an antiferromagnetic layer, a pinning layer, a barrier layer, a free layer, a thermal expansion material and a noble metal layer, wherein the antiferromagnetic layer is made of a hard magnetic antiferromagnetic material, the pinning layer is arranged on the antiferromagnetic layer, the pinning layer is made of a metal or a semi-metal with high spin polarizability, the barrier layer is arranged on the pinning layer, the free layer is arranged on the barrier layer, the free layer is made of a soft magnetic material with weak magnetic anisotropy, holes are formed in the free layer, the thermal expansion material is filled in the holes, the noble metal layer is arranged on the free layer, the thermal expansion material is in contact with the noble metal layer, and the noble metal layer absorbs heat from the environment so as to change the temperature of the free layer and the thermal expansion material. In the invention, the pinning layer, the barrier layer and the free layer form a magnetic tunnel junction. When in application, the invention is placed in an environment to be tested; while applying a magnetic field to the invention. And determining the temperature of the environment to be measured by measuring the change of the magnetoresistance of the magnetic tunnel junction in the environment to be measured. In the invention, the noble metal layer absorbs heat from the environment, so that the thermal expansion material expands, thereby changing the stress inside the barrier layer and the free layer, further changing the quantum tunneling property of the barrier layer and the spin state in the free layer, and further changing the magnetoresistance of the magnetic tunnel junction. Since the magnetoresistance of the magnetic tunnel junction depends heavily on the quantum tunneling characteristics of the barrier layer and the spin state in the free layer, the present invention has an advantage of high temperature detection sensitivity. In addition, the invention is based on the traditional electrical principle, and the equipment is simple.

The present invention will be described in further detail below with reference to the accompanying drawings.

Drawings

FIG. 1 is a schematic diagram of a high sensitivity magnetic tunnel junction temperature detector.

FIG. 2 is a schematic diagram of yet another high sensitivity magnetic tunnel junction temperature detector.

FIG. 3 is a schematic diagram of yet another high sensitivity magnetic tunnel junction temperature detector.

In the figure: 1. an antiferromagnetic layer; 2. a pinning layer; 3. a barrier layer; 4. a free layer; 5. a hole; 6. a noble metal layer; 7. particles of piezoelectric material.

Detailed Description

The technical scheme of the invention is further explained by combining the attached drawings.

Example 1

The invention provides a high-sensitivity magnetic tunnel junction temperature detector, which comprises an antiferromagnetic layer 1, a pinning layer 2, a barrier layer 3, a free layer 4, a thermal expansion material and a noble metal layer 6, as shown in figure 1. The material of the antiferromagnetic layer 1 is a hard magnetic antiferromagnetic material, and specifically, the material of the antiferromagnetic layer 1 is IrMn, PtMn, FeMn. The pinned layer 2 is placed on an antiferromagnetic layer. The material of the pinning layer 2 is a metal or semimetal having high spin polarizability, and specifically, the material of the pinning layer 2 is Co, Fe, CoFe, CoFeB, CoFeAl alloy. A barrier layer 3 is disposed on the pinned layer 2. The material of the barrier layer 3 is alumina or magnesia. The free layer 4 is disposed on the barrier layer 3. The material of the free layer 4 is a soft magnetic material with weak magnetic anisotropy, and specifically, the material of the free layer 4 is a NiFe alloy, a CoFe alloy, or a CoFeB alloy. The free layer 4 is provided with holes 5. The size of the holes is not limited herein. The holes 5 are arranged periodically, and the period of the holes 5 is square or rectangular, which is not limited herein. The thermal expansion material fills the hole 5. A noble metal layer 6 is disposed on the free layer 4 and a thermally expansive material is in contact with the noble metal layer 6. The thermal expansion material is an insulating thermal expansion material. Upon heating, the thermally expansive material is capable of expanding, but the thermally expansive material is not electrically conductive. The thermally expandable material may be rubber or other polymeric material. The thermal expansion material changes the stress in the free layer 4 when it expands.

In the present invention, the pinned layer 2, the barrier layer 3, and the free layer 4 form a magnetic tunnel junction. When in application, the invention is placed in an environment to be tested; while applying a magnetic field to the invention. And determining the temperature of the environment to be measured by measuring the change of the magnetoresistance of the magnetic tunnel junction in the environment to be measured. In the present invention, the noble metal layer 6 absorbs heat from the environment, so that the thermal expansion material expands, thereby changing the stress inside the barrier layer 3 and the free layer 4, thereby changing the quantum tunneling characteristic of the barrier layer 3 and the spin state in the free layer 4, and thus changing the magnetoresistance of the magnetic tunnel junction. Since the magnetoresistance of the magnetic tunnel junction depends heavily on the quantum tunneling characteristic of the barrier layer 3 and the spin state in the free layer 4, the present invention has an advantage of high temperature detection sensitivity. In addition, the invention is based on traditional electricity and has simple equipment.

In the present invention, the noble metal layer 6 can be used not only as an electrode to measure the magnetoresistance of the magnetic tunnel junction, but also as a good conductor of heat, the noble metal layer 6 is in contact with the outside, and the noble metal layer can transfer the heat of the outside to the thermal expansion material, thereby causing the thermal expansion material to expand.

In the present invention, the noble metal layer 6 is preferably gold. The gold material not only has good heat conduction characteristic, so that the thermal expansion material generates more deformation, but also has good electric conduction characteristic, and is used for measuring the magnetoresistance of the magnetic tunnel junction.

In addition, in the present invention, the thermal expansion material is also in contact with the barrier layer 3, and when the temperature of the thermal expansion material increases, the quantum tunneling characteristics of the barrier layer 3 are also changed. In addition, when the thermally expandable material expands, the interface between the free layer 4 and the barrier layer 3 is also changed, thereby changing the quantum tunneling probability of electrons passing through the interface. Therefore, when the environmental temperature changes, the magnetoresistance of the magnetic tunnel junction can change greatly, thereby realizing high-sensitivity temperature detection.

Example 2

On the basis of example 1, as shown in fig. 2, the bottom of the hole 5 is thick and the top of the hole 5 is thin. Thus, the thermal expansion material is more at the bottom of the hole 5; there is less thermal expansion material on top of the hole 5. Thus, when the thermal expansion material absorbs the same amount of heat, the expansion generated at the bottom of the hole 5 is greater, and the bottom of the hole 5 is in contact with the barrier layer 3, which is also close to the interface between the barrier layer 3 and the free layer 4, and thus the interface between the barrier layer 3 and the free layer 4 is changed more. Therefore, the arrangement of the present embodiment can change the quantum tunneling characteristics of the barrier layer 3 more, and change the quantum tunneling probability of the interface between the barrier layer 3 and the free layer 4 more. That is, when the thermal expansion material absorbs the same amount of heat, the magnetoresistance of the magnetic tunnel junction is changed more, so that temperature detection with higher sensitivity can be achieved.

Example 3

On the basis of embodiment 2, as shown in fig. 3, piezoelectric material particles 7 are further included, and the piezoelectric material particles 7 are placed in the thermal expansion material in the hole 5. When the thermal expansion material expands, the piezoelectric material particles 7 are subjected to pressure, thereby generating electric charges on the surfaces of the piezoelectric material particles 7. These charges are very close to the free layer 4 and the barrier layer 3, so that the local electric field in the vicinity of the free layer 4 and the barrier layer 3 is changed, the quantum tunneling characteristic of the barrier layer 3 and the conductive characteristic of the free layer 4 are changed, and thus, higher-sensitivity temperature detection is realized.

Further, grains 7 of piezoelectric material are disposed on the surface of the barrier layer 3. That is, a part of the surface of the piezoelectric material particles 7 is in contact with the barrier layer 3. Thus, when the thermal expansion material expands, the electric charges on the surface of the piezoelectric material particles 7 can change the local electric field near the barrier layer 3, so that the quantum tunneling property of the barrier layer 3 is changed, the magnetoresistance of the magnetic tunnel junction is changed more, and the temperature detection with higher sensitivity is realized. In addition, the above technical effects can be achieved also by the piezoelectric material particles 7 having a large size, the size of the piezoelectric material particles 7 being larger than the thickness of the free layer 4, the piezoelectric material particles 7 being partially in contact with the barrier layer 3, the piezoelectric material particles 7 being partially embedded in the noble metal layer 6, but such a design structure is simple, it is not necessary to limit the size of the piezoelectric material particles 7, and the fabrication is easy.

The above embodiments are merely illustrative of the technical ideas and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the contents of the present invention and implement the present invention, and not to limit the protection scope of the present invention. All equivalent changes and modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.