阅读说明：本技术 一种石墨烯高灵敏温度传感器 (High-sensitivity graphene temperature sensor ) 是由 于孟今 于 2021-08-25 设计创作，主要内容包括：本发明涉及温度传感领域,具体提供了一种石墨烯高灵敏温度传感器。钉扎层置于反铁磁层上,钉扎层的材料为自旋性极化率高的金属或半金属,势垒层置于钉扎层上,石墨烯层置于势垒层上,自由层置于石墨烯层上,自由层的材料为磁各向异性弱的软磁材料,石墨烯层延伸出势垒层和自由层,用以从环境中吸收热量。在本发明中,钉扎层、势垒层/石墨烯层、自由层形成磁隧道结。应用时,应用磁场作用于本发明；同时,将本发明置于待测环境中。通过测量置于待测环境时和常温时,磁隧道结的磁电阻的差异,确定待测环境的温度。本发明利用了磁隧道结的量子隧穿特性,具有温度探测灵敏度高的优点。(The invention relates to the field of temperature sensing, and particularly provides a graphene high-sensitivity temperature sensor. 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 graphene layer is arranged on the barrier layer, the free layer is arranged on the graphene layer, the free layer is made of soft magnetic material with weak magnetic anisotropy, and the graphene layer extends out of the barrier layer and the free layer to absorb heat from the environment. In the invention, the pinning layer, the barrier layer/graphene layer and the free layer form a magnetic tunnel junction. When in application, the magnetic field is applied to the invention; meanwhile, the invention is placed in an environment to be tested. The temperature of the environment to be measured is determined by measuring the difference between the magnetoresistance of the magnetic tunnel junction when placed in the environment to be measured and the magnetoresistance at room temperature. The invention utilizes the quantum tunneling characteristic of the magnetic tunnel junction and has the advantage of high temperature detection sensitivity.)

1. A graphene high-sensitivity temperature sensor is characterized by comprising an antiferromagnetic layer, a pinning layer, a barrier layer, a graphene layer and a free layer, wherein the antiferromagnetic layer is made of hard magnetic antiferromagnetic materials, 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 graphene layer is arranged on the barrier layer, the free layer is arranged on the graphene layer, the free layer is made of soft magnetic materials with weak magnetic anisotropy, and the graphene layer extends out of the barrier layer and the free layer.

2. The graphene high-sensitivity temperature sensor according to claim 1, wherein: holes are arranged in the graphene layer on the barrier layer.

3. The graphene high-sensitivity temperature sensor according to claim 2, wherein: the shape of the hole is round, square or rectangular.

4. The graphene high-sensitivity temperature sensor according to claim 3, wherein: the holes are periodically arranged.

5. The graphene high-sensitivity temperature sensor according to claim 4, wherein: the period is a square period.

6. The graphene high-sensitivity temperature sensor according to claim 5, wherein: the size of the holes is less than 100 nanometers.

7. The graphene high-sensitivity temperature sensor according to any one of claims 1 to 6, wherein: the number of graphene layers in the graphene layer is less than 6.

8. The graphene high-sensitivity temperature sensor according to claim 7, wherein: the free layer is made of NiFe alloy, CoFe alloy and CoFeB alloy.

9. The graphene high-sensitivity temperature sensor according to claim 8, wherein: the pinning layer is made of Co, Fe, CoFe, CoFeB and CoFeAl alloy.

10. The graphene high-sensitivity temperature sensor according to claim 9, wherein: the material of the antiferromagnetic layer is IrMn, PtMn and FeMn.

Technical Field

The invention relates to the field of temperature sensing, in particular to a graphene high-sensitivity temperature sensor.

Background

The temperature sensor is used to measure temperature information of a given space and convert the temperature information into a signal of a characteristic. The temperature sensors commonly used at present are thermistor type temperature sensors and optical fiber temperature sensors. The detection sensitivity of the conventional thermistor type temperature sensor or optical fiber temperature sensor is low, and the requirement of high-sensitivity temperature detection in special fields such as superconducting research cannot be met.

Disclosure of Invention

In order to solve the above problems, the present invention provides a graphene high-sensitivity temperature sensor, which includes an antiferromagnetic layer, a pinning layer, a barrier layer, a graphene layer, and a free layer, wherein the antiferromagnetic layer is made of a hard magnetic antiferromagnetic material, the pinning layer is disposed on the antiferromagnetic layer, the pinning layer is made of a metal or a semimetal with high spin polarizability, the barrier layer is disposed on the pinning layer, the graphene layer is disposed on the barrier layer, the free layer is disposed on the graphene layer, the free layer is made of a soft magnetic material with weak magnetic anisotropy, and the graphene layer extends out of the barrier layer and the free layer.

Furthermore, holes are arranged in the graphene layer on the barrier layer.

Further, the shape of the hole is circular, square or rectangular.

Further, the holes are periodically arranged.

Further, the period is a square period.

Further, the size of the holes is less than 100 nanometers.

Further, the number of graphene layers in a graphene layer is less than 6.

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 graphene high-sensitivity temperature sensor which comprises an antiferromagnetic layer, a pinning layer, a barrier layer, a graphene layer and a free layer, wherein the antiferromagnetic layer is made of 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 graphene layer is arranged on the barrier layer, the free layer is arranged on the graphene layer, the free layer is made of soft magnetic material with weak magnetic anisotropy, and the graphene layer extends out of the barrier layer and the free layer. In the invention, the pinning layer, the barrier layer/graphene layer and the free layer form a magnetic tunnel junction. When in application, the magnetic field is applied to the invention; meanwhile, the invention is placed in an environment to be tested. The temperature of the environment to be measured is determined by measuring the difference between the magnetoresistance of the magnetic tunnel junction when placed in the environment to be measured and the magnetoresistance at room temperature. In the invention, the part of the graphene layer extending out of the barrier layer and the free layer absorbs heat from the environment to be measured, and the temperature of the barrier layer is changed through the heat transfer of the graphene layer, so that the quantum tunneling characteristic of the barrier layer is changed, and the magnetoresistance of the magnetic tunnel junction is changed. The invention has the advantage of high temperature detection sensitivity because the magnetoresistance of the magnetic tunnel junction is heavily dependent on the quantum tunneling characteristics of the barrier layer.

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 graphene high-sensitivity temperature sensor.

Fig. 2 is a schematic diagram of another graphene high-sensitivity temperature sensor.

In the figure: 1. an antiferromagnetic layer; 2. a pinning layer; 3. a barrier layer; 4. a graphene layer; 5. a free layer; 6. and (4) holes.

Detailed Description

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

Example 1

The invention provides a graphene high-sensitivity temperature sensor, which comprises an antiferromagnetic layer 1, a pinning layer 2, a barrier layer 3, a graphene layer 4 and a free layer 5, 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 is IrMn, PtMn, FeMn. The pinned layer 2 is placed on the antiferromagnetic layer 1. 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 graphene layer 4 is disposed on the barrier layer 3. That is, the graphene layer 4 is laid on the barrier layer 3 in a chemical vapor deposition manner. Because the graphene layer prepared by the chemical vapor deposition method has higher purity. The free layer 5 is disposed on the graphene layer 4, the free layer 5 is made of a soft magnetic material with weak magnetic anisotropy, and specifically, the free layer 5 is made of a NiFe alloy, a CoFe alloy, or a CoFeB alloy. The alloy can be prepared by a mode of co-electron beam evaporation coating, and a sample prepared by the electron beam evaporation coating has higher purity. Graphene layer 4 extends beyond barrier layer 3 and free layer 5, that is to say, graphene layer 4 partially stretches beyond barrier layer 3 and free layer 5, forms the extension, and the extension is used for the temperature of probing the environment, absorbs the heat in the environment, because graphite alkene is the good conductor of heat, so graphene layer 4 can be good with heat transfer for barrier layer 3. The barrier layer 3 has a thickness of less than 3 nanometers so that the barrier layer 3/graphene layer 4 composite layer can eliminate magnetic exchange coupling between the pinned layer 2 and the free layer 5 and can form quantum tunneling between the pinned layer 2 and the free layer 5. In the present invention, the barrier layer 3 and the graphene layer 4 constitute a composite layer, and they perform the function of a barrier.

In the present invention, the pinning layer 2, the barrier layer 3/graphene layer 4 composite layer, and the free layer 5 form a magnetic tunnel junction. That is, the graphene layer 4 also performs the role of a potential barrier. When in application, the magnetic field is applied to the invention; meanwhile, the invention is placed in the environment with the temperature to be measured. The temperature of the environment to be measured is determined by measuring the difference between the magnetoresistance of the magnetic tunnel junction when placed in the environment to be measured and the magnetoresistance at room temperature. In the invention, the part of the graphene layer 4 extending out of the barrier layer 3 and the free layer 5 absorbs heat from the environment to be measured, and the temperature of the barrier layer 3 is changed through the heat transfer of the graphene layer 4, so that the quantum tunneling characteristic of the composite layer of the barrier layer 3/the graphene layer 4 is changed, and the magnetoresistance of the magnetic tunnel junction is changed. Since the magnetoresistance of the magnetic tunnel junction depends heavily on the quantum tunneling characteristics of the barrier layer 3 and the graphene layer 4, the present invention has an advantage of high temperature detection sensitivity.

In the present invention, the graphene layer 4 is used not only to absorb heat from the environment but also to transfer heat to the barrier layer 3, and electrons are easily quantum tunneled through the graphene layer 4. In addition, when the temperature changes, the quantum tunneling characteristics of the graphene layer 4 itself also change. In summary, the graphene layer 4 has a good effect in many aspects of the present invention.

Example 2

On the basis of embodiment 1, as shown in fig. 2, holes 6 are provided in the graphene layer 4 on the barrier layer 3, the holes 6 are circular, square, rectangular, or rhombic, the holes 6 are periodically arranged, and the arrangement period of the holes 6 is a square period or a rectangular period. In this way, although the graphene layer 4 can transfer heat from the environment to the barrier layer 3, the contact area is small, and therefore, a small amount of heat is transferred to the barrier layer 3, and the quantum tunneling characteristics of the barrier layer 3 are less changed. Therefore, the present embodiment is suitable for measuring temperature in a higher temperature environment.

Further, the size of the holes is smaller than 100 nm, so that the temperature change in the barrier layer 3 is less, and thus the quantum tunneling characteristic of the barrier layer 3 is less changed, thereby enabling the present embodiment to be applied in a higher temperature environment.

Example 3

On the basis of example 2, the number of graphene layers in the graphene layer 4 is less than 6. Further, on the barrier layer 3, the number of graphene layers in the graphene layer 4 is less than 2, so that more electrons can quantum tunnel through from the barrier layer 3/graphene layer 4 composite layer. Since graphene is a good thermal conductor, the two graphene layers 4 can also achieve a good thermal conduction effect. Thus, when the environmental temperature changes, the quantum tunneling electron number of the barrier layer 3/graphene layer 4 composite layer changes more, the magnetoresistance of the magnetic tunnel junction changes more, and the temperature detection sensitivity is improved.

Example 4

In addition to embodiment 2, particles of the heat sink material are provided on the portion of the graphene layer 4 extending beyond the barrier layer 3 and the free layer 5. The size of the heat-absorbing material particles is larger than that of the graphene layer 4, the heat-absorbing material particles have more contact areas with the environment, and more heat can be absorbed from the environment, so that more heat is transferred to the barrier layer 3, the quantum tunneling characteristic of the barrier layer 3/graphene layer 4 composite layer is changed more, and the temperature detection with higher sensitivity is realized. In application, the number or size of the endothermic particles may be determined according to the temperature range of the environment to be measured, so that the quantum tunneling characteristics of the barrier layer 3/graphene layer 4 are more sensitive to temperature.

Example 5

On the basis of embodiment 1, the number of partial layers of the graphene layer 4 extending out of the barrier layer 3 and the free layer 5 is large; the number of partial layers of the graphene layer 4 sandwiched between the barrier layer 3 and the free layer 5 is small. In this way, the portion of the graphene layer 4 extending beyond the barrier layer 3 and the free layer 5 can absorb more heat; when the temperature changes, the electron tunneling characteristics of the portion of the graphene layer 4 sandwiched between the barrier layer 3 and the free layer 5 change more, thereby realizing a temperature detection with higher sensitivity.

Furthermore, at the part that layer 4 stretches out barrier layer 3 and free layer 5 on layer 4, be equipped with the clearance between layer in layer 4 to have more area of contact with the environment, can absorb more heat from the environment, thereby change the quantum tunneling characteristic of barrier layer 3/layer 4 composite layer more, thereby realize the temperature probe of higher sensitivity.

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.