JP-2026075857-A - Magnetoresistive element and magnetic sensor equipped therewith

JP2026075857AJP 2026075857 AJP2026075857 AJP 2026075857AJP-2026075857-A

Abstract

[Problem] To provide a magnetoresistive element that has a magnetization free layer which is magnetized in a spiral shape in the absence of an external magnetic field and whose magnetization direction changes when an external magnetic field is applied, and which exhibits good linearity of output with respect to an external magnetic field. [Solution] The magnetoresistive element 1 has a magnetization free layer 6 that is magnetized in a spiral shape in the absence of an external magnetic field and whose magnetization direction changes when an external magnetic field is applied, a magnetization fixed layer 4 whose magnetization direction is fixed with respect to the external magnetic field, and a non-magnetic layer 5 located between the magnetization free layer 6 and the magnetization fixed layer 4, and the magnetization free layer 6, magnetization fixed layer 4 and non-magnetic layer 5 are arranged in the Z direction. The non-magnetic layer 5 has an interface surface 51 that is in contact with the magnetization free layer 6, and when viewed from the Z direction, a part 68 of the magnetization free layer 6 is outside the outer peripheral portion 53 of the interface surface 51. [Selection Diagram] Figure 1

Inventors

小林尚史

Assignees

ＴＤＫ株式会社

Dates

Publication Date: 20260511
Application Date: 20241023

Claims (18)

A magnetization free layer that is magnetized in a spiral pattern in the absence of an external magnetic field, and whose magnetization direction changes when the external magnetic field is applied, A magnetization-fixed layer whose magnetization direction is fixed with respect to the external magnetic field, It has a non-magnetic layer located between the magnetization free layer and the magnetization fixed layer, The magnetization-free layer, the magnetization-fixed layer, and the non-magnetic layer are arranged in a first direction. The non-magnetic layer has an interface in contact with the magnetization-free layer, A magnetoresistive element in which, when viewed from the first direction, a portion of the magnetization free layer is located outside the outer periphery of the interface.
The magnetoresistive element according to claim 1, wherein a step is formed between the non-magnetic layer and the magnetization-free layer.
The magnetoresistive element according to claim 1, wherein the side surface of the non-magnetic layer and the side surface of the magnetization-free layer are continuously connected.
The magnetoresistive element according to claim 1, wherein at least one step is formed on the side surface of the magnetization free layer.
The magnetoresistive element according to claim 1, wherein the magnetization-free layer has a first portion and a second portion arranged in the first direction, the first portion is in contact with the non-magnetic layer and has a smaller area and thickness than the second portion.
The magnetoresistive element according to claim 1, wherein the side surface of the magnetization free layer is formed continuously.
The magnetoresistive element according to claim 6, wherein at least one corner is formed on the side surface of the magnetization free layer.
The magnetoresistive element according to claim 1, wherein the magnetization fixed layer is magnetized in a second direction perpendicular to the first direction, and the length of the magnetization fixed layer in the second direction is longer than the length in the third direction perpendicular to the first and second directions.
The magnetization fixed layer is magnetized in the first direction, The magnetization free layer has a first center line parallel to the first direction, The magnetoresistive element according to claim 1, wherein, when viewed from the first direction, the magnetization fixed layer is separated from the first center line.
The magnetoresistive element according to claim 9, wherein the magnetization-fixed layer and the non-magnetic layer have a second center line parallel to the first center line.
The magnetoresistive element according to claim 10, wherein the magnetization fixing layer has a through hole through which the first center line passes.
The magnetoresistive element according to claim 1, wherein the magnetization free layer is rotationally symmetric when viewed from the first direction.
The magnetoresistive element according to claim 12, wherein the magnetization free layer is circular when viewed from the first direction.
The magnetoresistive element according to claim 13, wherein the magnetization free layer has a thickness of 20 nm or more and a diameter of 0.3 μm or more and 3 μm or less.
The magnetoresistive element according to claim 13, wherein, when viewed from the first direction, the interface is circular, and the diameter of the interface is 0.1 μm or more and 80% or less of the diameter of the magnetized free layer.
The laminate comprises the magnetization free layer, the magnetization fixed layer, and the non-magnetic layer, and a substrate. The laminate and the substrate are arranged in the first direction. The magnetoresistive element according to claim 1, wherein the magnetization free layer is located between the substrate and the magnetization fixed layer.
The laminate comprises the magnetization free layer, the magnetization fixed layer, and the non-magnetic layer, and a substrate. The laminate and the substrate are arranged in the first direction. The magnetoresistive element according to claim 1, wherein the magnetization fixed layer is located between the substrate and the magnetization free layer.
A magnetic sensor having a magnetoresistive element according to any one of claims 1 to 17.

Description

This disclosure relates to a magnetoresistive element and a magnetic sensor equipped therewith. Patent Document 1 describes a magnetoresistive element having a spirally magnetized free layer in the absence of an external magnetic field (zero magnetic field state). The center (core) of the spiral shape is located at the center of the free layer in the zero magnetic field state, but when an external magnetic field is applied, it moves towards the periphery of the free layer. Patent No. 6355706 specification These are schematic cross-sectional and plan views of a magnetoresistive element according to the first embodiment.This is a schematic cross-sectional view of a comparative example magnetoresistive element.This is a conceptual diagram showing the magnetic curve and magnetization state of the magnetized free layer.This is a schematic cross-sectional view of a magnetoresistive element according to a modified example of the first embodiment.This is a schematic cross-sectional view of a magnetoresistive element according to the second embodiment.These are schematic cross-sectional and plan views of a magnetoresistive element according to the third embodiment.These are schematic cross-sectional and plan views of a magnetoresistive element according to the fourth embodiment.This is a schematic plan view of the magnetized free layer of a magnetoresistive element according to the fifth embodiment.This is a schematic diagram of the magnetic sensor according to the sixth embodiment.This graph shows the relationship between the diameter of the non-magnetic layer interface, the resistance of the magnetoresistive element, and the output of the magnetic sensor.This graph shows the relationship between the diameter of the interface of the non-magnetic layer and the sensitivity and linearity of the magnetic sensor.This graph shows the relationship between the diameter and thickness of the magnetized free layer and the rate of vortex formation. Several embodiments of this disclosure will be described with reference to the drawings. In the following description and drawings, the first direction is referred to as the Z direction, the second direction as the X direction, and the third direction as the Y direction. The Z direction is the stacking direction of the laminate 2, and the X and Y directions are the in-plane directions of each layer of the laminate 2. The X, Y, and Z directions are orthogonal to each other. The direction from the substrate 3 towards the laminate 2 is referred to as the +Z direction, and the direction from the laminate 2 towards the substrate 3 is referred to as the -Z direction. When the magnetization fixed layer 4 is magnetized in a direction perpendicular to the Z direction, the magnetization direction of the magnetization fixed layer 4 is referred to as the X direction. In the drawings, the arrows attached to the magnetization fixed layer 4 indicate the magnetization direction of the magnetization fixed layer 4. (First embodiment) Figure 1(a) shows a cross-sectional view of a magnetoresistive element 1 according to the first embodiment of the present disclosure, and Figure 1(b) shows a cross-sectional view along the line A-A in Figure 1(a). The magnetoresistive element 1 has a laminate 2 and a silicon substrate 3, and the laminate 2 and the substrate 3 are arranged in the Z direction. Although not shown, other layers such as electrode layers are provided between the laminate 2 and the substrate 3, and the laminate 2 is separated from the substrate 3. The laminate 2 comprises a magnetized fixed layer 4, a non-magnetic layer 5, and a magnetized free layer 6. These layers 4-6 are arranged in the +Z direction in the order of magnetized free layer 6, non-magnetic layer 5, and magnetized fixed layer 4. The magnetized free layer 6 is located between the substrate 3 and the magnetized fixed layer 4 in the Z direction. The magnetized free layer 6 and the non-magnetic layer 5 are in contact with each other, and the non-magnetic layer 5 and the magnetized fixed layer 4 are in contact with each other. At any position in the Z direction, the cross-sectional shape of the laminate 2 is circular, and the magnetized free layer 6, non-magnetic layer 5, and magnetized fixed layer 4 form a cylinder or disk with a common Z-direction central axis CL. The side surface 61 of the magnetized free layer 6 is formed continuously in the Z direction and does not change discontinuously. That is, there are no steps on the side surface 61 of the magnetized free layer 6. The magnetization-fixed layer 4 is a magnetic layer whose magnetization direction is fixed in the X direction with respect to an external magnetic field. The magnetization-fixed layer 4 can be formed from CoFeB or the like. Although not shown in the diagram, the magnetization-fixed layer 4 may also have a configuration in which an inner magnetization-fixed layer in contact with the non-magnetic layer 5, an intermediate layer made of ruthenium, iridium, etc., and a