JP-2026074767-A - Magnetoresistive elements, magnetic sensors, and detectors

JP2026074767AJP 2026074767 AJP2026074767 AJP 2026074767AJP-2026074767-A

Abstract

[Problem] To provide a magnetoresistive element that can respond to a wide range of magnetic fields. [Solution] The magnetoresistive element 100 comprises a first magnetic layer 11, a second magnetic layer 12, and a third magnetic layer 13 whose magnetization direction changes in response to an external magnetic field, a dielectric layer 20 located between the first magnetic layer 11 and the second magnetic layer 12, and a first non-magnetic layer 31 located between the first magnetic layer 11 and the third magnetic layer 13. The first magnetic layer 11 is located between the second magnetic layer 12 and the third magnetic layer 13. The magnetization direction D1 of the first magnetic layer 11 and the magnetization direction D2 of the second magnetic layer 12 are stabilized in an antiparallel state when no external magnetic field is applied. The magnetization direction D1 of the first magnetic layer 11 and the magnetization direction D3 of the third magnetic layer 13 are stabilized in an antiparallel state when no external magnetic field is applied. [Selection Diagram] Figure 1

Inventors

西谷雄
中谷友也

Assignees

国立研究開発法人物質・材料研究機構
パナソニックホールディングス株式会社

Dates

Publication Date: 20260507
Application Date: 20241021

Claims (16)

A first magnetic layer, a second magnetic layer, and a third magnetic layer whose magnetization direction changes in response to an external magnetic field, wherein the first magnetic layer is laminated so as to be located between the second magnetic layer and the third magnetic layer, A dielectric layer located between the first magnetic layer and the second magnetic layer, The first magnetic layer and the third magnetic layer are located between them, and the first non-magnetic layer is located between them. The magnetization direction of the first magnetic layer and the magnetization direction of the second magnetic layer are stabilized in an antiparallel state when no external magnetic field is applied. The magnetization direction of the first magnetic layer and the magnetization direction of the third magnetic layer stabilize in an antiparallel state when no external magnetic field is applied. Magnetoresistive element.
The first non-magnetic layer is formed such that the first magnetic layer and the third magnetic layer exhibit a second-order or higher-order antiferromagnetic RKKY (Rudeman, Kittel, Kasuya, Yoshida) interaction. The magnetoresistive element according to claim 1.
The first non-magnetic layer contains ruthenium as its main component, The thickness of the first non-magnetic layer is 1.0 nm or more and 5.0 nm or less. The magnetoresistive element according to claim 1.
The dielectric layer mainly comprises an alloy consisting of magnesium oxide, aluminum oxide, or magnesium-aluminum oxide. The magnetoresistive element according to claim 1.
Each of the first magnetic layer and the second magnetic layer has an alloy layer mainly composed of cobalt, iron, and boron. The magnetoresistive element according to claim 1.
A fourth magnetic layer and a fifth magnetic layer whose magnetization direction is fixed in one direction, A second non-magnetic layer facing the first non-magnetic layer via the third magnetic layer, The present invention further comprises a third non-magnetic layer facing the dielectric layer via the second magnetic layer, The fourth magnetic layer faces the third magnetic layer via the second non-magnetic layer, The fifth magnetic layer faces the second magnetic layer via the third non-magnetic layer. The magnetoresistive element according to claim 1.
The second non-magnetic layer is formed such that the third magnetic layer and the fourth magnetic layer exhibit a second-order or higher-order antiferromagnetic RKKY interaction. The third magnetic layer is formed such that the second magnetic layer and the fifth magnetic layer exhibit a second-order or higher-order antiferromagnetic RKKY interaction. The magnetoresistive element according to claim 6.
A first antiferromagnetic layer facing the third magnetic layer via the fourth magnetic layer, The present invention further comprises a second antiferromagnetic layer facing the second magnetic layer via the fifth magnetic layer, The magnetoresistive element according to claim 6.
Each of the first antiferromagnetic layer and the second antiferromagnetic layer mainly contains a manganese-iridium alloy, a manganese-platinum alloy, or a manganese-nickel alloy. The magnetoresistive element according to claim 8.
The first antiferromagnetic layer, The fourth magnetic layer, The second non-magnetic layer, The third magnetic layer, The first non-magnetic layer, The first magnetic layer and Dielectric layer and The second magnetic layer and The third non-magnetic layer, The fifth magnetic layer, It has a stacked structure in which a second antiferromagnetic layer and a second antiferromagnetic layer are stacked in this order. The first non-magnetic layer is formed such that the first magnetic layer and the third magnetic layer exhibit a second-order or higher-order antiferromagnetic RKKY interaction. Magnetoresistive element.
A magnetoresistive element according to any one of claims 1 to 10, A first electrode electrically connected to one end of the magnetoresistive element, The magnetoresistive element comprises a second electrode electrically connected to the other end of the magnetoresistive element, Magnetic sensor.
The system detects magnetic field components in directions different from the magnetization direction of the first magnetic layer and the magnetization direction of the second magnetic layer when no external magnetic field is applied. The magnetic sensor according to claim 11.
The system comprises a plurality of the aforementioned magnetoresistive elements, The plurality of magnetoresistive elements are electrically connected to each other in at least one form, such as in series and in parallel. The magnetic sensor according to claim 11.
The magnetic sensor according to claim 11, It comprises a magnetic scale with at least one north pole and one south pole aligned, The positional change between the magnetic sensor and the magnetic scale is detected. Detector.
The magnetic sensor according to claim 11, It comprises a magnetic scale with at least one north pole and one south pole aligned, The speed of the positional change between the magnetic sensor and the magnetic scale is detected. Detector.
The magnetic sensor according to claim 11, It comprises a magnetic scale with at least one north pole and one south pole aligned, The acceleration of the change in position between the magnetic sensor and the magnetic scale is detected. Detector.

Description

This disclosure relates to magnetoresistive elements, magnetic sensors, and detectors. Magnetic sensors utilizing a TMR (Tunnel MagnetoResistance) structure are known. Patent Document 1 describes a magnetic sensor having two free layers made of magnetic material and a tunnel barrier layer as a TMR structure. In the TMR structure described in Patent Document 1, the magnetization directions of the two free layers are stably antiparallel to each other when no external magnetic field is applied. As the external magnetic field strength increases, the magnetization directions of the two free layers approach the direction of the external magnetic field. International Publication No. 2024/034206 Figure 1 is a cross-sectional view showing a magnetoresistive element according to Embodiment 1.Figure 2 is a top view showing a magnetoresistive element according to Embodiment 1.Figure 3 shows an example of the magnetization direction in a magnetic tunnel junction structure.Figure 4 is a diagram illustrating the change in resistance of a magnetoresistive element due to an external magnetic field.Figure 5 is a diagram illustrating the change in the magnetization direction of the first magnetic layer when the magnetization direction of the third magnetic layer does not change due to the external magnetic field.Figure 6 illustrates the change in the magnetization direction of the first magnetic layer when the magnetization direction of the third magnetic layer changes due to an external magnetic field.Figure 7 is a conceptual diagram showing the dependence of the strength of the exchange coupling energy due to the RKKY interaction on the thickness of the non-magnetic layer.Figure 8 is a cross-sectional view showing a magnetoresistive element according to a modified example of Embodiment 1.Figure 9 is a perspective view showing a magnetic sensor according to Embodiment 2.Figure 10 is a perspective view showing a first example of a magnetic sensor according to a modification of Embodiment 2.Figure 11 is a perspective view showing a second example of a magnetic sensor according to a modification of Embodiment 2.Figure 12 is a perspective view showing a third example of a magnetic sensor according to a modification of Embodiment 2.Figure 13 is a perspective view showing a detector according to Embodiment 3.Figure 14 is a schematic diagram showing the stacked structure of the magnetic sensor in Example 1.Figure 15 is a schematic diagram showing the stacked structure of the magnetic sensor in Comparative Example 1.Figure 16 is a schematic diagram showing the stacked structure of the magnetic sensor in Comparative Example 2.Figure 17 shows the relationship between the exchange coupling energy due to the RKKY interaction and the thickness of the non-magnetic layer.Figure 18 shows the magnetoresistance characteristics of magnetic sensors in the examples and comparative examples. (Summary of this disclosure) As an overview of this disclosure, examples of magnetoresistive elements, magnetic sensors, and detectors relating to this disclosure are shown below. For example, a magnetoresistive element according to a first aspect of this disclosure comprises a first magnetic layer, a second magnetic layer, and a third magnetic layer whose magnetization direction changes in response to an external magnetic field. The first magnetic layer comprises a first magnetic layer, a second magnetic layer, and a third magnetic layer stacked so as to be located between the second magnetic layer and the third magnetic layer; a dielectric layer located between the first magnetic layer and the second magnetic layer; and a first non-magnetic layer located between the first magnetic layer and the third magnetic layer. The magnetization direction of the first magnetic layer and the magnetization direction of the second magnetic layer are stabilized in an antiparallel state when no external magnetic field is applied, and the magnetization direction of the first magnetic layer and the magnetization direction of the third magnetic layer are also stabilized in an antiparallel state when no external magnetic field is applied. As a result, the rotation angle of the magnetization direction of the first magnetic layer 11 due to the application of an external magnetic field to the magnetoresistive element becomes an angle relative to the magnetization direction of the third magnetic layer. Here, since the magnetization directions of the first magnetic layer and the third magnetic layer are antiparallel when no external magnetic field is applied, when an external magnetic field is applied to the magnetoresistive element, the magnetization direction of the third magnetic layer rotates in a direction that cancels out the rotation of the magnetization direction of the first magnetic layer. Therefore, the magnetization direction of the first magnetic layer becomes less susceptible to rotation by the external magnetic field, and in the magnetoresistive element according to t