Tunnel magnetoresistive effect element and magnetic detection device provided with same

Abstract

A top-pin type tunnel magnetoresistive effect element (a TMR film 10) according to the present invention comprises a free magnetic layer 12, an insulating barrier layer 13, and a fixed magnetic layer 19, which are stacked in this order. The fixed magnetic layer 19 has a self-pinning structure in which a second magnetic layer 14, a non-magnetic intermediate layer 15, and a first magnetic layer 16 are stacked in this order from the insulating barrier layer 13 side, and the fixed magnetization directions of the second magnetic layer 14 and the first magnetic layer 16 are antiparallel. The second magnetic layer 14 is obtained by stacking a first CoFe layer 141, a CoFeB layer (a crystal orientation reset layer 142), an NiFe layer (a crystal orientation promotion layer 143), and a second CoFe layer 144 in this order from the insulating barrier layer 13 side, the first magnetic layer is an FeCo layer 16, and the FeCo layer 16 has an Fe composition ratio of 40 to 80 at.% and a film thickness of 1.6 to 4.5 nm. Consequently, the tunnel magnetoresistive effect element according to the present invention is excellent in terms of strong magnetic field resistance and has a small hysteresis.

Description

Tunnel-type magnetoresistance effect element and magnetic detection device including the same

[0001] The present invention relates to a tunneling magnetoresistive element and a magnetic detection device including the same.

[0002] Magnetoresistive elements, whose electrical resistance varies with an external magnetic field, are used in magnetic detection devices, etc. Examples of magnetoresistive elements include giant magnetoresistive elements (GMR films, GMR elements) and tunneling magnetoresistive elements (TMR films, TMR elements).

[0003] Patent Document 1 describes a TMR sensor with a bottom-pinned (bottom spin valve) structure including a free magnetic layer, a tunnel barrier layer (Mg / MgO / Mg), and a pinned layer (AP1 / coupling layer (Ru) / AP2). It also describes that the AP1 layer in contact with the tunnel barrier layer in the TMR sensor is made of Co or CoFe, and that the TMR sensor may have a top-pinned (top spin valve) structure.

[0004] Patent Document 2 describes that in a top-pin type TMR element consisting of a free magnetic layer, a junction layer (tunnel barrier layer, MgO), a reference layer, and an exchange pinning layer, the reference layer in contact with the junction layer is formed with a stacked structure of CoFe, CoFeB, or CoFeB / CoFe.

[0005] In a top-pin type TMR element, the crystallinity of the pinned magnetic layer stacked on the insulating barrier layer (tunnel barrier layer) decreases and becomes amorphous, which reduces the layer separation of each layer constituting the pinned magnetic layer with a self-pinned structure. Neither Patent Document 1 nor Patent Document 2 takes into consideration the problem of the pinned magnetic layer's crystallinity decreasing due to the influence of the insulating barrier layer in a top-pin type TMR element. Conventionally, a top-pin type TMR element has had the problem of being unable to increase magnetic field resistance and the rate of resistance change ΔMR because the crystallinity of the pinned magnetic layer stacked on the insulating barrier layer decreases.

[0006] Patent Document 3 describes a top-pin type tunneling magnetoresistance effect element in which a free magnetic layer, an insulating barrier layer, and a fixed magnetic layer are stacked in this order to increase the resistance to strong magnetic fields and the rate of resistance change, the fixed magnetic layer having a self-pinned structure in which a second magnetic layer, a non-magnetic intermediate layer, and a first magnetic layer are stacked in this order from the insulating barrier layer side, the fixed magnetization directions of the second magnetic layer and the first magnetic layer are antiparallel, and the second magnetic layer has a crystal orientation promoting layer.

[0007] JP 2008-300840 A JP 2011-238342 A JP 2020-136471 A

[0008] Patent Document 3 describes that the inclusion of a crystal orientation promoting layer in the second magnetic layer increases the high magnetic field resistance and resistance change rate of a top-pin type tunnel magnetoresistance effect element. However, it does not describe a configuration for reducing hysteresis. If the hysteresis of the pinned magnetic layer is large, magnetization dispersion occurs after a large magnetic field is applied, making the resistance change rate ΔMR more likely to deteriorate. Therefore, an object of the present invention is to provide a top-pin type tunnel magnetoresistance effect element with excellent high magnetic field resistance and small hysteresis, and a magnetic detection device using the same.

[0009] In one aspect, the present invention, which is provided to solve the above-mentioned problems, provides a top-pinned tunneling magnetoresistive element having a free magnetic layer, an insulating barrier layer, and a pinned magnetic layer stacked in this order, wherein the pinned magnetic layer has a second magnetic layer, a non-magnetic intermediate layer, and a first magnetic layer stacked in this order from the insulating barrier layer side, and has a self-pinned structure in which the pinned magnetization directions of the second magnetic layer and the first magnetic layer are antiparallel, the second magnetic layer has a first CoFe layer, a CoFeB layer, a NiFe layer, and a second CoFe layer stacked in this order from the insulating barrier layer side, the first magnetic layer is an FeCo layer, and the Fe in the FeCo layer has a composition ratio of 40 to 80 at. % and a film thickness of 1.6 to 4.5 nm.

[0010] The second magnetic layer is stacked in the following order from the insulating barrier layer: a first CoFe layer, a CoFeB layer, a NiFe layer, and a second CoFe layer. The first magnetic layer is an FeCo layer, and the FeCo layer has an Fe composition ratio of 40 to 80 at. % and a film thickness of 1.6 to 4.5 nm. This reduces hysteresis. Furthermore, the Hex / Hc ratio can be increased, improving resistance to strong magnetic fields.

[0011] The first CoFe layer may have a thickness of 0.3 to 3.6 nm, the CoFeB layer may have a thickness of 0.5 to 4.1 nm, the NiFe layer may have a thickness of 0.5 to 8.1 nm, and the second CoFe layer may have a thickness of 0.3 to 3.9 nm. The first CoFe layer may have a Co composition ratio of 20 to 80 at. %, and the CoFeB layer may have a composition ratio of (Co 100-X FeX) 100-Y B Y In the above, X may be 25 to 100 at. %, Y may be 10 to 30 at. %, the Ni composition ratio of the NiFe layer may be 40 to 100 at. %, and the Co composition ratio of the second CoFe layer may be 60 to 100 at. This configuration reduces hysteresis and provides a tunneling magnetoresistance effect element with good resistance to strong magnetic fields.

[0012] The first magnetic layer has a positive saturation magnetization Ms and a negative saturation magnetization Ms - The difference between Ms and Ms - ) for 2Ms, the magnetization amount M0 in zero magnetic field when changing from a saturation state on the negative side to a saturation state on the positive side, and the magnetization amount M0 in zero magnetic field when changing from a saturation state on the positive side to a saturation state on the positive side. - The difference between (M0-M0 - ) may be 1% or less. By setting the ratio of ΔM0 to 2Ms to 1% or less, the magnetization dispersion of the first magnetic layer is suppressed. As a result, the hysteresis of the first magnetic layer is reduced, resulting in a tunneling magnetoresistance effect element with good resistance to strong magnetic fields.

[0013] The tunneling magnetoresistive element may have a ΔMR change rate of 2% or less, as expressed by the following formula (1), where ΔMRa is the resistance change rate before a magnetic field of 1 T is applied and ΔMRb is the resistance change rate after a magnetic field of 1 T is applied: ΔMR change rate (%)=[(ΔMRa−ΔMRb) / ΔMRa]×100 (1)

[0014] In order to solve the above-mentioned problems, in another aspect, the present invention provides a magnetic detection device in which a plurality of tunneling magnetoresistive elements according to the present invention are formed on the same substrate, and the plurality of tunneling magnetoresistive elements include those in which the fixed magnetic layers have different fixed magnetization directions. By using the tunneling magnetoresistive element according to the present invention, a magnetic detection device having excellent resistance to strong magnetic fields and a high rate of resistance change can be obtained.

[0015] In the tunneling magnetoresistive element of the present invention, the first magnetic layer is an FeCo layer, and the FeCo layer has an Fe composition ratio of 40 to 80 at. % and a film thickness of 1.6 to 4.5 nm, which strengthens the antiferromagnetic magnetic interaction with the second magnetic layer, which is formed by stacking a first CoFe layer, a CoFeB layer, a NiFe layer, and a CoFe layer in this order from the insulating barrier layer side, thereby stabilizing the self-pinned structure. Therefore, it is possible to provide a top-pin tunneling magnetoresistive element that has small hysteresis, excellent resistance to strong magnetic fields, and a high resistance change rate.

[0016] FIG. 1 is an explanatory diagram schematically illustrating the film configuration of a top-pin type TMR film. FIG. 2 is an explanatory diagram relating to the cause of weakening of the magnetic field resistance of a top-pin type TMR film. FIG. 3 is a graph schematically illustrating differences in magnetization curves due to differences in the orientation of the crystal structure of the pinned magnetic layer. FIG. 4 is a circuit block diagram of a magnetic detection device of the present invention. FIG. 5 is a diagram schematically illustrating a process of forming a pinned magnetic layer in a manufacturing method of a magnetic detection device of the present invention. FIG. 6 is a schematic diagram illustrating the configuration of a TMR film of Example 1. FIG. 7 is a graph illustrating the film thickness dependency of a crystal orientation reset layer in the TMR film of Example 1. FIG. 8 is a schematic diagram illustrating the configuration of a TMR film of Example 2. FIG. 9 is a graph illustrating the film thickness dependency of a crystal orientation promotion layer in the TMR film of Example 2. FIG. 10 is a schematic diagram illustrating the configuration of a TMR film of Example 3. FIG. 11 is a graph illustrating the film thickness dependency of a second CoFe layer in the TMR film of Example 3. FIG. 12 is a schematic diagram illustrating the configuration of a TMR film of Example 4. FIG. 13 is a graph illustrating the film thickness dependency of a first CoFe layer in the TMR film of Example 4. FIG. 14 is a schematic diagram illustrating the configuration of a TMR film of Example 5. 1 is a graph showing the film thickness dependence of the crystalline orientation reset layer in the TMR film of Example 5. FIG. 1 is a schematic diagram showing the configuration of the TMR film of Example 6. FIG. 2 is a graph showing the film thickness dependence of the crystalline orientation promoting layer in the TMR film of Example 6. FIG. 3 is a schematic diagram showing the configuration of the TMR film of Example 7. FIG. 4 is a graph showing the film thickness dependence of the second CoFe layer in the TMR film of Example 7. FIG. 5 is a graph explaining parameters for evaluating the composition dependence of the second CoFe layer at the Ru interface. FIG. 6 is a schematic diagram showing the configuration of the film of Example 8. FIG. 7 is a graph showing the composition dependence of the second CoFe layer in the film of Example 8. FIG. 8 is a graph explaining parameters used for evaluating the film thickness dependence of the first magnetic layer constituting the film in Examples 9 and 10. FIG. 9 is a schematic diagram showing the configuration of the film of Example 9. FIG. 10 is a graph showing the relationship between the applied magnetic field and the magnetization amount of the first magnetic layer when the thicknesses of the first magnetic layer in the film of Example 9 are 1.5 nm, 2.4 nm, and 4.5 nm. FIG. 11 is a graph showing the film thickness dependence of M0 / Ms of the first magnetic layer. 10 is a graph showing the dependence of Hex on the film thickness of the first magnetic layer; FIG. 11 is a graph showing the dependence of Hc on the film thickness of the first magnetic layer; FIG. 12 is a graph showing the dependence of Hex / Hc and ΔM0 / 2Ms on the film thickness of the first magnetic layer; FIG. 13 is a graph showing the dependence of ΔM0 / 2Ms and ΔMR change rate on the film thickness of the first magnetic layer; and FIG. 14 is a schematic diagram of the configuration of the TMR film of Example 10.10 is a graph showing the relationship between the thickness of the first magnetic layer and the second CoFe layer and the normalized bridge output in Example 10. FIG. 11 is a schematic diagram of the film configuration in Example 11. FIG. 12 is a graph showing the relationship between the composition of the first magnetic layer and Hc in Example 11.

[0017] When a strong magnetic field is applied to a magnetoresistive element, the magnetization state of the pinned magnetic layer disperses, irreversibly degrading the resistance change rate of the magnetoresistive element. For this reason, self-pinned magnetoresistive elements have been proposed, which have a pinned magnetic layer with excellent magnetic field resistance. In self-pinned magnetoresistive elements, the first and second magnetic layers of the pinned magnetic layer are coupled by antiferromagnetic magnetic interaction (hereinafter referred to as antiferromagnetic coupling or RKKY interaction) via a nonmagnetic intermediate layer. The magnetization pinning force of the pinned magnetic layer is based on the high coercivity of the first magnetic layer farther from the free magnetic layer. Therefore, by stacking an antiferromagnetic layer on the first magnetic layer (on the side opposite the nonmagnetic intermediate layer) and applying an exchange coupling magnetic field Hex to the first magnetic layer, the resistance change rate of the magnetoresistive element is prevented from deteriorating due to a strong magnetic field.

[0018] In a so-called bottom-pin (bottom spin-valve) magnetoresistive element in which a free magnetic layer is formed after a pinned magnetic layer, an antiferromagnetic layer is formed before the pinned magnetic layer, and a first magnetic layer of the pinned magnetic layer is laminated on the antiferromagnetic layer. When a high-coercivity FeCo layer is laminated as the first magnetic layer on the antiferromagnetic layer, there is a problem that the squareness ratio (squareness) of the magnetization curve of the FeCo layer deteriorates. If the squareness ratio of the FeCo layer deteriorates and the first magnetic layer cannot generate sufficient remanent magnetization, antiferromagnetic coupling does not occur between the two ferromagnetic layers (the first magnetic layer and the second magnetic layer), and the pinned magnetic layer no longer functions.

[0019] In a top-pin (top spin valve) type magnetoresistive element, in which a pinned magnetic layer is formed after a free magnetic layer, an antiferromagnetic layer is formed after the pinned magnetic layer, and the antiferromagnetic layer is laminated on the first magnetic layer of the pinned magnetic layer. In a giant magnetoresistive element (sometimes referred to as a "GMR film"), by forming a first magnetic layer of an FeCo layer with good magnetization curve squareness and then laminating an antiferromagnetic layer on the first magnetic layer, it is possible to suppress dispersion of the magnetic anisotropy of the FeCo layer.

[0020] However, unlike GMR films, tunneling magnetoresistance effect elements (sometimes referred to as "TMR films") cannot form pinned magnetic layers with good magnetic field resistance, even in top-pin configurations. This is thought to be due to the presence of a layer different from that in GMR films between the free magnetic layer and pinned magnetic layer. It is speculated that the difference in crystal structure between oxides such as Al2O3 and MgO used as insulating barrier layers in TMR films and Cu used as a non-magnetic material layer in GMR films changes the crystallinity of the pinned magnetic layer, thereby affecting magnetic field resistance.

[0021] FIG. 2 is an explanatory diagram of the cause of the weakening of the magnetic field resistance of a top-pin type TMR film, and shows an estimate of the crystalline orientation of the layers constituting each film before annealing (as-deposited) for an example of a GMR film and a TMR film.

[0022] As shown in the figure, in the top-pin type GMR film, the crystal orientation of Cu used as the non-magnetic material layer is different from that of Co used as the pinned magnetic layer. 90at.% Fe 10at.% (In this specification and drawings, the at. % is omitted as appropriate, and the composition is also referred to as 90CoFe, indicating only the percentage of one of the elements.) Similarly, it has a face-centered cubic fcc

[111] lattice structure. Therefore, the 90CoFe of the pinned magnetic layer is stacked on a Cu layer with a homogeneous crystal structure, resulting in a high atomic density with sufficient crystal orientation. Therefore, the pinned magnetic layer has strong antiferromagnetic coupling via the Ru layer and good magnetic field resistance.

[0023] In contrast, in top-pin TMR films, the crystal structure of the MgO used as the insulating barrier layer is NaCl-type. Therefore, the 90CoFe pinned magnetic layer is stacked on an MgO layer with a significantly different crystal structure and interatomic distance. Because 90CoFe has difficulty spontaneously orienting its crystals, it is presumed that when stacked on MgO, it is unable to achieve sufficient crystal orientation and becomes non-oriented or amorphous. Ru and 60FeCo stacked on 90CoFe also become non-oriented or amorphous, similar to 90CoFe. Therefore, the crystallinity of each layer constituting the pinned magnetic layer is low, resulting in poor layer separation. As a result, the antiferromagnetic coupling via Ru is weakened, and ferromagnetic coupling becomes dominant, resulting in low magnetic field resistance.

[0024] In other words, in a top-pin type TMR film, the insulating barrier layer provided between the free magnetic layer and the pinned magnetic layer has a crystal structure different from that of the adjacent layers, which causes the crystal orientation to be disrupted, causing each layer constituting the pinned magnetic layer to become unoriented or amorphous, weakening the antiferromagnetic coupling and reducing the magnetic field resistance.

[0025] 3 is a graph showing the effect of differences in the crystallinity of each layer constituting the pinned magnetic layer on the magnetization curve of a TMR element. In this figure, the solid line shows the magnetization curve of a TMR film having pinned magnetic layers with high crystallinity and atomic density, while the dashed line shows the magnetization curve of a TMR film having pinned magnetic layers with low crystallinity and atomic density.

[0026] In a TMR film having a pinned magnetic layer with high crystallinity, i.e., strong crystalline orientation, the region where the free magnetic layer undergoes magnetization reversal and the region where the pinned magnetic layer (first magnetic layer or second magnetic layer) undergoes magnetization reversal are clearly separated on the magnetization curve. This means that the pinned magnetic layer constituting the TMR film has good layer separation. The degree of layer separation of the pinned magnetic layer can be evaluated by the plateau magnetic field (Hp(+), Hp(-)). Here, the "plateau magnetic field" is the magnitude of the magnetic field at which the magnetization reversal of the magnetized pinned layer begins, and is defined as the magnitude of the magnetic field at which the Ms·t (saturation magnetization per unit area, at the end of magnetization reversal of the free magnetic layer) of the pinned magnetic layer fluctuates by 2%.

[0027] In contrast, in a TMR film with a pinned magnetic layer that has low crystallinity, i.e., weak crystalline orientation, the region where the free magnetic layer reverses magnetization and the region where the pinned magnetic layer (first magnetic layer or second magnetic layer) reverses magnetization are not clearly separated on the magnetization curve. This indicates that the pinned magnetic layer constituting the TMR film does not have good layer separation, and the magnetization reversal of the free magnetic layer and the pinned magnetic layer occurs continuously. If the layer separation of the pinned magnetic layer is poor, no plateau field appears on the magnetization curve.

[0028] In the top-pin TMR film shown on the right side of Figure 2, the crystalline orientation of the insulating barrier layer and the pinned magnetic layer stacked thereon is weak, resulting in weak antiferromagnetic coupling (RKKY interaction) via Ru in the pinned magnetic layer. As a result, magnetization reversal occurs continuously between the free magnetic layer and the first and second magnetic layers in the pinned magnetic layer. In this case, as shown by the dashed line in Figure 3, an antiparallel magnetization state between the pinned magnetic layer and the free magnetic layer is hardly formed, and the TMR film does not have a high rate of resistance change (ΔMR).

[0029] 1 is an explanatory diagram illustrating the film configuration of a top-pin type TMR film 10 of the present invention. As shown in the figure, the TMR film 10 is a top-pin type tunnel magnetoresistance element formed by laminating an underlayer (seed layer) 11, a free magnetic layer 12, an insulating barrier layer 13, a second magnetic layer 14, a non-magnetic intermediate layer 15, a first magnetic layer 16, an antiferromagnetic layer 17, and a protective layer 18 in this order. The second magnetic layer 14, the non-magnetic intermediate layer 15, and the first magnetic layer 16 form a pinned magnetic layer 19.

[0030] The underlayer 11 is a layer that is first formed on a substrate or lower electrode layer (not shown). There are no particular restrictions on the material, but examples of the material that can be used include NiFeCr and Ru.

[0031] The free magnetic layer 12 is laminated on the underlayer 11, and its material and structure are not limited. For example, it can be formed as a single-layer structure, a laminated structure, a laminated ferrimagnetic structure, or the like, using a CoFe alloy (cobalt-iron alloy) or a NiFe alloy (nickel-iron alloy) as its material.

[0032] The insulating barrier layer 13 is laminated on the free magnetic layer 12. Examples of materials that can be used for the insulating barrier layer 13 include Al2O3, TiOx, and MgO. From the viewpoint of increasing the resistance change rate of the TMR film 10, MgO is preferred.

[0033] The pinned magnetic layer 19 is formed by stacking the second magnetic layer 14, the non-magnetic intermediate layer 15, and the first magnetic layer 16 in this order from the insulating barrier layer 13 side. The second magnetic layer 14 and the first magnetic layer 16 are ferromagnetic layers, and have a self-pinned structure in which the magnetization directions are pinned antiparallel by antiferromagnetic coupling via the non-magnetic intermediate layer 15. The sensitivity axis direction of the TMR film 10 is the pinned magnetization direction of the second magnetic layer 14.

[0034] The second magnetic layer 14 is formed by laminating a first CoFe layer 141, a crystal orientation reset layer 142, a crystal orientation promoting layer 143, and a second CoFe layer 144 in this order from the insulating barrier layer 13 side.

[0035] By laminating the first CoFe layer 141 having a bcc crystal structure on the insulating barrier layer 13, the TMR film 10 can have a large resistance change rate. 100-X A CoFe layer having a Co composition ratio X of 20 to 80 at. % is preferred. The CoFe layer can form a body-centered cubic (bcc) structure under conditions that allow for the formation of a highly crystalline layer. The thickness of the CoFe layer is preferably 0.3 nm or more, and more preferably 0.5 nm or more, from the viewpoint of providing a TMR film 10 with a large resistance change rate.

[0036] The crystal orientation reset layer 142 can be formed of an amorphous material. The amorphous material can be, for example, a CoFeB layer and / or a Ta layer. "Amorphous" means that no crystalline structure can be observed using a transmission electron microscope (TEM).

[0037] The composition of CoFeB forming the crystal orientation reset layer 142 is not particularly limited. 100-X Fe X ) 100-Y B YIn the formula (I), the composition ratio X is preferably 25 to 100 at. %, and the composition ratio Y is preferably 10 to 30 at. %. When the crystal orientation reset layer 142 is formed of amorphous CoFeB, from the viewpoint of isolating the influence of the insulating barrier layer 13, the thickness thereof is preferably 0.5 nm or more, more preferably 0.8 nm or more, and even more preferably 1.0 nm or more. From the viewpoint of strengthening the magnetization fixing force of the fixed magnetic layer 19 due to antiferromagnetic coupling, the thickness thereof is preferably 3.0 nm or less, more preferably 2.5 nm or less, and even more preferably 2.0 nm or less.

[0038] When a Ta layer is used as the crystal orientation reset layer 142, it is preferably a beta-Ta layer having a thickness of 0.1 to 0.4 nm, which can separate the influence of the insulating barrier layer 13 and magnetically couple the layers stacked above and below the Ta layer, thereby strengthening the magnetization pinning force of the pinned magnetic layer 19 due to antiferromagnetic coupling.

[0039] The crystal orientation reset layer 142 may be a single layer or multiple layers. For example, if it has a stacked structure of a CoFeB layer and a Ta layer, the influence of the insulating barrier layer 13 can be further reduced. This results in good layer separation, with each layer stacked on the crystal orientation reset layer 142 being clearly distinguished.

[0040] By providing the crystal orientation reset layer 142, the influence of the insulating barrier layer 13 can be reset, and the influence of the crystalline structure of the insulating barrier layer 13 on the subsequently stacked layers can be further suppressed. As a result, the crystalline structure of the layer stacked on the crystal orientation promoting layer 143 becomes favorable and has a high atomic density, resulting in a pinned magnetic layer 19 with good layer separation between the layers. Therefore, the self-pinned structure of the pinned magnetic layer can be stabilized.

[0041] The crystalline orientation promoting layer 143 is formed, for example, from a metal having an fcc

[111] lattice structure, and promotes the crystalline orientation of the second CoFe layer 144, the non-magnetic intermediate layer 15, and the first magnetic layer 16 formed thereon, resulting in a layer with high crystallinity. An example of a metal having an fcc

[111] lattice structure is a ferromagnetic material whose main component is nickel, such as NiFe. Components other than Ni include Co, Nb, Ta, and the like, in addition to Fe. The composition of NiFe constituting the NiFe layer of the crystalline orientation promoting layer 143 is not particularly limited, but Ni X Fe 100-X In the above, the Ni composition ratio X is preferably 40 to 100 at. %. 81.5NiFe(Pc permalloy) is preferred because it has a high tendency to spontaneously orient in fcc

[111] and has excellent soft magnetic properties.

[0042] The thickness of the crystal orientation promoting layer 143 is preferably 0.5 nm or more, more preferably 1.0 nm or more, and even more preferably 1.5 nm or more from the viewpoint of promoting crystal orientation. From the viewpoint of strengthening the magnetization fixing force of the pinned magnetic layer 19 due to antiferromagnetic coupling, the thickness is preferably 5.0 nm or less, more preferably 4.0 nm or less, and even more preferably 3.0 nm or less.

[0043] The second CoFe layer 144 functions as an RKKY-enhancing layer, and by being stacked adjacent to the crystal orientation promoting layer 143 rather than the insulating barrier layer 13, it becomes a layer with excellent crystallinity and high atomic density. For example, by stacking the second CoFe layer 144 on the crystal orientation promoting layer 143 having an fcc

[111] lattice structure, it is possible to form the second CoFe layer 144 with an fcc

[111] lattice structure, which has excellent crystallinity and high atomic density. As a result, the nonmagnetic intermediate layer 15 and the first magnetic layer 16 stacked on the second CoFe layer 144 also have high crystallinity. This strengthens the antiferromagnetic coupling of the pinned magnetic layer 19 and stabilizes the self-pinned structure.

[0044] The composition of the second CoFe layer 144 is not particularly limited. However, from the viewpoints of excellent soft magnetic properties, suppressing dispersion in the magnetic field direction during film formation in a magnetic field and facilitating magnetization, and enhancing the RKKY interaction via Ru, Co X Fe 100-XIn the above, the composition ratio X is preferably 60 to 100 at.

[0045] From the viewpoint of enhancing the above-mentioned effects, the thickness of the second CoFe layer 144 is preferably 0.3 to 3.9 nm, and more preferably 0.3 to 2.3 nm.

[0046] The non-magnetic intermediate layer 15 is made of Ru. If the thickness of the non-magnetic intermediate layer 15 made of Ru is set to 0.3 to 0.45 nm or 0.75 to 0.95 nm, the second magnetic layer 14 and the first magnetic layer 16 can be antiferromagnetically coupled.

[0047] The first magnetic layer 16 is made of Co X Fe 100-X A material with a high coercive force Hc, such as (X=40 to 80), is used. After the first magnetic layer 16 is formed (produced), the first magnetic layer 16 and the second magnetic layer 14 are coupled in an antiparallel manner via the nonmagnetic intermediate layer 15, and function as the pinned magnetic layer 19. From the viewpoint of increasing the magnetic field resistance of the pinned magnetic layer 19, it is preferable that the first magnetic layer 16 and the second magnetic layer 14 be adjusted so that the difference in magnetization (saturation magnetization Ms x layer thickness t) is approximately equal (substantially zero).

[0048] The first magnetic layer 16 may have a ratio of ΔM0 to 2Ms of 1% or less. 2Ms is the sum of the saturation magnetization amount Ms on the positive side of the first magnetic layer 16 and the saturation magnetization amount Ms on the negative side. - ΔM0 is the difference between the magnetization amount M0 of the first magnetic layer 16 in zero magnetic field when changing the first magnetic layer 16 from a negative saturation state to a positive saturation state and the magnetization amount M0 of the first magnetic layer 16 in zero magnetic field when changing the first magnetic layer 16 from a positive saturation state to a positive saturation state. - The difference between (M0-[M0 - ]).

[0049] By setting the ratio of ΔM0 to 2Ms of the first magnetic layer to 1% or less, i.e., ΔM0 / 2Ms to 0.01 or less, the magnetization dispersion of the first magnetic layer can be suppressed, resulting in a smaller hysteresis and a TMR film 10 with good resistance to strong magnetic fields.

[0050] By setting the ratio of ΔM0 to 2Ms of the first magnetic layer to 1% or less, it is possible to provide a TMR film 10 that has a ΔMR change rate of 2% or less, as expressed by the following formula (1), and that has excellent resistance to strong magnetic fields: ΔMR change rate (%)=[(ΔMRa-ΔMRb) / ΔMRa]×100 (1) (In formula (1), ΔMRa is the resistance change rate before a 1 T magnetic field is applied to the TMR film 10, and ΔMRb is the resistance change rate after a 1 T magnetic field is applied.)

[0051] The antiferromagnetic layer 17 uses exchange coupling to fix (pin) the magnetization direction of the first magnetic layer 16. The material is not particularly limited, but examples include antiferromagnetic materials containing an element X (where X is one or more elements selected from the group consisting of Pt, Pd, Ir, Rh, Ru, and Os) and one or both of Mn and Cr. The material of the protective layer 18 is not particularly limited, but examples include Ru, Ta, and the like.

[0052] The top-pin type TMR film 10 of this embodiment shown in Fig. 1 has the above-mentioned configuration, which improves the layer separation of the pinned magnetic layer. As a result, a plateau field (Hp(-)) appears in the magnetization curve, as shown by the solid line in Fig. 3, and the resistance change rate becomes sufficiently high.

[0053] 4 is a circuit block diagram of a magnetic detection device 50 of this embodiment. The magnetic detection device 50 is configured with a full-bridge circuit 40. In the figure, arrows indicate the magnetization directions of the second magnetic layers 14 of the fixed magnetic layer 19. The full-bridge circuit 40 is configured such that two series circuits 42a and 42b, in which the order of the TMR films 10 having different fixed magnetization directions of the second magnetic layers 14 is swapped, are connected in parallel between a power supply voltage Vdd 41 and a ground potential GND 44.

[0054] The differential output between the output potential of the midpoint terminal 43a of the series circuit 42a and the output potential of the midpoint terminal 43b of the series circuit 42b, which constitute the full-bridge circuit 40, is obtained as a magnetic field detection output voltage.

[0055] In the magnetic detection device 50, the orientation of the free magnetic layer 12 (see FIG. 1) of the TMR film 10 changes to follow the direction of the external magnetic field. At this time, the resistance value of the TMR film 10 changes depending on the relative angle between the fixed magnetization direction of the second magnetic layer 14 and the magnetization direction of the free magnetic layer 12.

[0056] When the direction or strength of the external magnetic field changes, the detected output voltage of the full-bridge circuit 40 also fluctuates accordingly. Therefore, the external magnetic field can be detected based on the detected output voltage obtained from the full-bridge circuit 40. Although Fig. 4 shows a magnetic detection device 50 configured to be capable of detecting magnetic fields in the horizontal direction as viewed from the plane of the drawing, if combined with a magnetic detection device configured to be capable of detecting magnetic fields in the vertical direction as viewed from the plane of the drawing, magnetic fields in the vertical and horizontal directions can be detected simultaneously.

[0057] 5 is a diagram schematically illustrating a method for manufacturing the magnetic detection device 50 of FIG. 4, showing the relationship between the substrate and the direction of application of the magnetic field in the film formation process. In this diagram, a case where a TMR film 10 is formed as a magnetoresistive effect element will be described.

[0058] 5A, two TMR films 10 are formed on a substrate. In the process of depositing the first magnetic layer 16 (see FIG. 1) of the pinned magnetic layer 19 in the TMR film 10, the first magnetic layer 16 is deposited while applying a magnetic field to the substrate in the direction indicated by the white arrow in the 180° direction. RKKY interaction occurring between the first magnetic layer 16 and the second magnetic layer 14 allows the formation of a TMR film 10 in which the pinned magnetization direction of the second magnetic layer 14 is in the 0° direction indicated by the black arrow.

[0059] 5(b), the direction of the magnetic field indicated by the white arrow applied in the step of depositing the first magnetic layer 16 is changed to the 0° direction, and a TMR film 10 having a pinned magnetic layer 19 with a different magnetization direction from that of the TMR film 10 formed in step (a) is formed on the same substrate. The pinned magnetization direction of the second magnetic layer 14 in the TMR film 10 formed in this step is the 180° direction indicated by the black arrow. Since the direction of the magnetic field application is determined by the relative relationship between the substrate and the magnetic field, either the substrate or the magnetic field application means may be moved to change the direction of the applied magnetic field.

[0060] In this way, by repeating the process of forming the pinned magnetic layer 19 while changing the direction of the applied magnetic field, it is possible to form TMR films 10 with pinned magnetic layers 19 having different pinned magnetization directions on the same substrate.

[0061] After the formation of a plurality of TMR films 10, each having a pinned magnetic layer 19 with different pinned magnetization directions, is completed on the substrate, annealing is performed in a magnetic field free state, in which no magnetic field is applied, to generate an exchange coupling magnetic field Hex between the first magnetic layer 16 and the antiferromagnetic layer 17 of the pinned magnetic layer 19. This allows the TMR films 10 to be aged to form a stable magnetic detection device 50.

[0062] Thereafter, a plurality of TMR films 10 formed on one substrate are connected together to form a full-bridge circuit 40 shown in FIG. 4, thereby completing the manufacture of the magnetic detection device 50.

[0063] The present invention will be explained in more detail below with reference to examples, but the scope of the present invention is not limited to these examples.

[0064] (Example 1 Influence of the thickness of the crystal orientation reset layer) On the lower electrode layer [Ta (10)], the underlayer: NiFeCr (4.2) / insulating barrier layer: MgO (2.0) / second magnetic layer: [first CoFe layer: 50CoFe (0.5) / crystal orientation reset layer: CoFeB (X) / crystal orientation promoting layer: NiFe (1.5) / second CoFe layer: 70CoFe (0.8)] / non-magnetic intermediate layer: Ru (0.4) / first magnetic layer: 60FeCo (Y) / antiferromagnetic layer: IrMn (8) / protective layer: [Ru (5) / Ta (15) / Ru (5)] was laminated in this order to manufacture a TMR film. In this example and the following examples, the numbers in parentheses indicate the thickness (nm) of each layer.

[0065] FIG. 6A is a schematic diagram of the TMR film configuration of this example. In the figure, ● indicates a layer whose thickness was varied to examine the effect of film thickness, and ◯ indicates a layer whose thickness was varied to equalize the magnetization of the second magnetic layer, which changes with the film thickness of the layer. In this example, TMR films were manufactured with the thickness X of the crystal orientation reset layer (CoFeB) set to 0.0, 0.3, 0.5, 0.6, and 0.7 nm, and the thickness Y of the first magnetic layer (60FeCo) set to a thickness (Y = 1.8 to 2.5 nm) that made the magnetization of the first and second magnetic layers (saturation magnetization Ms x layer thickness t) equal to that of the second magnetic layer.

[0066] FIG. 6B shows the MH curve of the TMR film of this example, and the relationship between the thickness X (nm) of the CoFeB film and the gradient (memu / cm) of the applied magnetic field ±1 kOe in the MH curve. 2 / kOe) is shown in the table below.

[0067] 6B and Table 1, it can be seen that when the CoFeB film thickness is 0.0 nm, the first magnetic layer and the second magnetic layer are ferromagnetically coupled. Furthermore, by setting the CoFeB film thickness to 0.5 nm or more, it was found that the antiferromagnetic coupling between the first magnetic layer and the second magnetic layer tends to be stabilized.

[0068] (Example 2 Influence of the thickness of the crystal orientation promoting layer) On the lower electrode layer [Ta (10)], underlayer: NiFeCr (4.2) / insulating barrier layer: MgO (2.0) / second magnetic layer: [first CoFe layer: 50CoFe (0.5) / crystal orientation reset layer: CoFeB (0.7) / crystal orientation promoting layer: NiFe (X) / second CoFe layer: 70CoFe (0.8)] / non-magnetic intermediate layer: Ru (0.4) / first magnetic layer: 60FeCo (Y) / antiferromagnetic layer: IrMn (8) / protective layer: [Ru (5) Ta (15) / Ru (5)] was laminated in this order to manufacture a TMR film.

[0069] Figure 7A is a schematic diagram of the TMR film configuration of this example. In this figure, ● indicates a layer whose thickness was varied to examine the effect of film thickness, and ◯ indicates a layer whose thickness was varied to equalize the magnetization amount of the second magnetic layer, which changes with the film thickness of the layer. In this example, TMR films were manufactured with the thickness X of the NiFe crystalline orientation promoting layer set to 0.0, 0.3, 0.5, 0.8, and 1.0 nm, and the thickness Y of the 60FeCo first magnetic layer set to a thickness (Y = 1.8 to 2.3 nm) that equalized the magnetization amounts of the first and second magnetic layers.

[0070] FIG. 7B shows the MH curve of the TMR film of this example, and the relationship between the thickness X (nm) of the CoFeB film and the gradient (memu / cm) of the applied magnetic field ±1 kOe in the MH curve. 2 / kOe) is shown in the table below.

[0071] 7B and Table 2, it can be seen that when the NiFe film thickness is 0.0 nm, the first magnetic layer and the second magnetic layer are ferromagnetically coupled. Furthermore, when the NiFe film thickness is 0.5 nm or more, the antiferromagnetic coupling between the first magnetic layer and the second magnetic layer tends to be stabilized.

[0072] (Example 3 Influence of the thickness of the second CoFe layer) On the lower electrode layer [Ta (10)], underlayer: NiFeCr (4.2) / insulating barrier layer: MgO (2.0) / second magnetic layer: [first CoFe layer: 50CoFe (0.5) / crystal orientation reset layer: CoFeB (0.7) / crystal orientation promoting layer: NiFe (1.5) / second CoFe layer: 70CoFe (X)] / non-magnetic intermediate layer: Ru (0.4) / first magnetic layer: 60FeCo (Y) / antiferromagnetic layer: IrMn (8) / protective layer: [Ru (5) / Ta (15) / Ru (5)] is stacked in this order to manufacture a TMR film.

[0073] 8A is a schematic diagram of the TMR film configuration of this example. In the figure, ● indicates a layer whose thickness was varied to examine the effect of film thickness, and ◯ indicates a layer whose thickness was varied to equalize the magnetization of the second magnetic layer, which changes with the film thickness of the layer. In this example, TMR films were manufactured in which the thickness X of the second CoFe layer (70CoFe) was 0.0, 0.15, 0.30, and 0.5 nm, and the thickness Y of the first magnetic layer (60FeCo) was set to a thickness (Y = 1.8 to 2.2 nm) such that the magnetization of the first and second magnetic layers was equal to that of the second magnetic layer.

[0074] FIG. 8B shows the MH curve of the TMR film of this example, and the relationship between the thickness X (nm) of the CoFeB film and the gradient (memu / cm) of the applied magnetic field ±1 kOe in the MH curve. 2 / kOe) is shown in the table below.

[0075] 8B and Table 3, it was found that when the thickness of the second CoFe layer was 0.0 nm, the first magnetic layer and the second magnetic layer were antiferromagnetically coupled, but the saturation magnetic field was small. By setting the thickness of the second CoFe layer to 0.30 nm or more, it was found that the antiferromagnetic coupling between the first magnetic layer and the second magnetic layer tended to be stabilized.

[0076] (Example 4 Influence of the film thickness of the first CoFe layer) On the lower electrode layer [Ta (3) / Cu (20) / Ta (3) / Cu (20) / Ta (35)], underlayer: NiFeCr (4.2) / free magnetic layer: [86NiFe (9.0) / CoFeB (1.0) / 50CoFe (0.6)] / insulating barrier layer: MgO (2.0) / second magnetic layer: [first CoFe layer: 50CoFe (X) / crystal orientation reset Layer: CoFeB (0.7) / Crystal orientation promoting layer: 81.5NiFe (1.5) / Second CoFe layer: 70CoFe (0.5) / Non-magnetic intermediate layer: Ru (0.4) / First magnetic layer: 60FeCo (Y) / Antiferromagnetic layer: IrMn (8.0) / Protective layer: [Ru (5.0) / Ta (15.0) / Ru (5.0)] was laminated in this order to produce a TMR film.

[0077] Figure 9A is a schematic diagram of the TMR film configuration of this example. In this figure, ● indicates a layer whose thickness was varied to examine the effect of film thickness, and ◯ indicates a layer whose thickness was varied to equalize the magnetization of the second magnetic layer, which changes with the film thickness of the layer. In this example, TMR films were manufactured with the film thickness X of the first CoFe layer (50CoFe) set to 0.0, 0.15, 0.3, 0.5, 1.0, 1.5, and 2.0 nm, and the film thickness Y of the first magnetic layer (60FeCo) set to a thickness (Y = 1.7 to 3.7 nm) that equalized the magnetization of the first and second magnetic layers.

[0078] 9B shows the relationship between the thickness X (nm) of the 50CoFeB film in the TMR film of this example and the resistance change (ΔR / Rmin (%)). As shown in the figure, ΔR / Rmin of the 50CoFeB film saturated at a film thickness of 0.3 nm. From this result, it can be said that the film thickness of the first CoFe layer in the second magnetic layer is preferably 0.3 nm or more.

[0079] (Example 5 Influence of the thickness of the crystal orientation reset layer) On the lower electrode layer [Ta (3) / Cu (20) / Ta (3) / Cu (20) / Ta (35)], an underlayer: NiFeCr (4.2) / free magnetic layer: [86NiFe (9.0) / CoFeB (1.0) / 50CoFe (0.6)] / insulating barrier layer: MgO (2.0) / second magnetic layer: [first CoFe layer: 50CoFe (0.3) / crystal orientation reset layer] The TMR film was manufactured by stacking the following layers in this order: first magnetic layer: CoFeB(X) / crystalline orientation promoting layer: 81.5NiFe(1.5) / second CoFe layer: 70CoFe(0.5) / non-magnetic intermediate layer: Ru(0.4) / first magnetic layer: 60FeCo(Y) / antiferromagnetic layer: IrMn(8.0) / protective layer: [Ru(5.0) / Ta(15.0) / Ru(5.0)].

[0080] FIG. 10A is a schematic diagram of the TMR film configuration of this example. In the figure, ● indicates a layer whose thickness was changed to examine the effect of film thickness, and ◯ indicates a layer whose thickness was changed to equalize the magnetization amount of the second magnetic layer, which changes with the film thickness of the layer. In this example, TMR films were manufactured with the thickness X of the crystal orientation reset layer: CoFeB film set to 0.0, 0.3, 0.5, 1.0, 1.5, and 2.0 nm, and the thickness Y of the first magnetic layer: 60FeCo film set to a thickness (Y = 1.6 to 3.2 nm) that made the magnetization amounts of the first and second magnetic layers equal to that of the second magnetic layer.

[0081] Figure 10B shows the relationship between the thickness X (nm) of the CoFeB film and the resistance change (ΔR / Rmin (%)) in the TMR film of this example. As shown in the figure, ΔR / Rmin of the 50CoFeB layer saturated at a film thickness of 0.5 nm, and tended to gradually increase as the film thickness increased beyond that. From this result, it can be said that the film thickness of the crystal orientation reset layer in the second magnetic layer is preferably 0.5 nm or more.

[0082] (Example 6 Influence of the thickness of the crystal orientation promoting layer) On the lower electrode layer [Ta (3) / Cu (20) / Ta (3) / Cu (20) / Ta (35)], an underlayer: NiFeCr (4.2) / free magnetic layer: [86NiFe (9.0) / CoFeB (1.0) / 50CoFe (0.6)] / insulating barrier layer: MgO (2.0) / second magnetic layer: [first CoFe layer: 50CoFe (0.3) / crystal orientation promoting layer] The TMR film was manufactured by stacking the following layers in this order: first magnetic layer: CoFeB(0.7) / crystalline orientation promoting layer: 81.5NiFe(X) / second CoFe layer: 70CoFe(0.5) / non-magnetic intermediate layer: Ru(0.4) / first magnetic layer: 60FeCo(Y) / antiferromagnetic layer: IrMn(8.0) / protective layer: [Ru(5.0) / Ta(15.0) / Ru(5.0)].

[0083] Figure 11A is a schematic diagram of the TMR film configuration of this example. In this figure, ● indicates a layer whose thickness was varied to examine the effect of film thickness, and ◯ indicates a layer whose thickness was varied to equalize the magnetization of the second magnetic layer, which changes with the film thickness of the layer. In this example, TMR films were manufactured with the thickness X of the crystalline orientation promoting layer (81.5NiFe) set to 0.0, 0.3, 0.5, 1.0, 1.5, 2.0, 3.0, and 4.0 nm, and the thickness Y of the first magnetic layer (60FeCo) set to a thickness (Y = 1.6 to 3.1 nm) that equalized the magnetization of the first and second magnetic layers.

[0084] Figure 11B shows the relationship between the thickness X (nm) of the 81.5NiFe film and ΔR / Rmin (%) in the TMR film of this example. As shown in the figure, ΔR / Rmin saturated at a film thickness of 0.5 nm for the 81.5NiFe film, and then tended to gradually decrease. From these results, it can be said that the film thickness of the crystalline orientation promoting layer in the second magnetic layer is preferably 0.5 nm or more.

[0085] (Example 7 Influence of the film thickness of the second CoFe layer) On the lower electrode layer [Ta (3) / Cu (20) / Ta (3) / Cu (20) / Ta (35)], an underlayer: NiFeCr (4.2) / free magnetic layer: [86NiFe (9.0) / CoFeB (1.0) / 50CoFe (0.6)] / insulating barrier layer: MgO (2.0) / second magnetic layer: [first CoFe layer: 50CoFe (0.3) / crystal orientation reset The TMR film was manufactured by stacking the following layers in this order: first magnetic layer: CoFeB (0.7) / crystalline orientation promoting layer: 81.5NiFe (1.5) / second CoFe layer: 70CoFe (X) / non-magnetic intermediate layer: Ru (0.4) / first magnetic layer: 60FeCo (Y) / antiferromagnetic layer: IrMn (8.0) / protective layer: [Ru (5.0) / Ta (15.0) / Ru (5.0)].

[0086] Figure 12A is a schematic diagram of the TMR film configuration of this example. In this figure, ● indicates a layer whose thickness was varied to examine the effect of film thickness, and ◯ indicates a layer whose thickness was varied to equalize the magnetization of the second magnetic layer, which changes with the film thickness of the layer. In this example, TMR films were manufactured with the film thickness X of the second CoFe layer (70CoFe) set to 0.0, 0.15, 0.3, 0.5, 1.0, 1.5, and 2.0 nm, and the film thickness Y of the first magnetic layer (60FeCo) set to a thickness (1.6 to 3.4 nm) that equalized the magnetization of the first and second magnetic layers.

[0087] The relationship between the thickness X (nm) of the second CoFe layer (70CoFe) and ΔR / Rmin (%) in the TMR film of this example is shown in Figure 12B, and the table below. As shown in the figure, ΔR / Rmin of the second CoFe layer saturated at a film thickness of 0.3 nm. From this result, it can be said that the film thickness of the second CoFe layer in the second magnetic layer is preferably 0.3 nm or more.

[0088] (Example 8: Composition Dependence of the Second CoFe Layer at the Ru Interface) Figure 13 is a graph showing the relationship between the applied magnetic field and ΔR / R (MR ratio), and parameters used to evaluate the composition dependence of the second CoFe layer at the Ru interface will be explained using this graph. As shown in this figure, in the graph of ΔR / R of the magnetoresistive film, which changes depending on the direction of the applied magnetic field, the maximum value of ΔR / R is ΔMR, the value of ΔR / R when a magnetic field of +5 kOe is applied is ΔMR(+5k), and the value of ΔR / R when a magnetic field of -5 kOe is applied is ΔMR(-5k). An ideal magnetoresistive film has a value of [ΔMR(+5k)-ΔMR(-5k)] / ΔMR=1.0.

[0089] In this example, the GMR film was manufactured by stacking the following in order: underlayer: NiFeCr (4.2) / free magnetic layer: [NiFe (7.0) / 90CoFe (0.5)] / non-magnetic material layer: Cu (2.0) / second magnetic layer: [first CoFe layer: 90CoFe (1.9) / second CoFe layer: xCoFe (0.5)] / non-magnetic intermediate layer: Ru (0.4) / first magnetic layer: 60FeCo (Y) / antiferromagnetic layer: IrMn (8) / protective layer: Ta (12).

[0090] Figure 14A is a schematic diagram of the GMR film configuration of this example. In this figure, ● indicates a layer whose composition ratio was changed to examine the effect of composition, and ◯ indicates a layer whose thickness was changed to equalize the magnetization of the second magnetic layer, which changes with the composition of the layer. In this example, GMR films were manufactured in which the Co composition ratio x in the second magnetic layer: [first CoFe layer: 90CoFe(1.9) / second CoFe layer: xCoFe(0.5)] was 0, 10, 20, 30, 40, 50, 60, 70, 80, 90, and 100 at. %, and the thickness Y of the first magnetic layer: 60FeCo was set to a thickness (1.9 to 2.05 nm) such that the magnetization of the first magnetic layer and the second magnetic layer was equal to that of the second magnetic layer.

[0091] 14B is a graph showing the composition dependency of the second CoFe layer. From the results shown in the figure, it was found that the FeCo at the interface with Ru in the second magnetic layer preferably has a Co composition ratio of 60 to 100 at. %.

[0092] (Example 9) Figure 15A is a graph explaining the parameters used to evaluate the film thickness dependency of the first magnetic layer constituting the film in Examples 9 and 10. The figure shows the relationship between the applied magnetic field and the magnetization amount of the film (saturation magnetization amount Ms x layer thickness t). The significance of each parameter shown in the figure is described below. 2Ms: saturation magnetization amount Ms on the positive side and saturation magnetization amount Ms on the negative side - Difference between Ms and Ms - ) △M0: Magnetization amount M0 in zero magnetic field when changing from a negative saturation state to a positive saturation state, and magnetization amount M0 in zero magnetic field when changing from a positive saturation state to a positive saturation state - The difference between (M0-M0 - ). Hex = sum of H0 and H0- (H0 + H0 - ) multiplied by 0.5. 2Hc: The magnetic field H0 at which the magnetization amount becomes 0 when changing from a saturated state on the negative side to a saturated state on the positive side, and the magnetic field H0 at which the magnetization amount becomes 0 when changing from a saturated state on the positive side to a saturated state on the negative side. - The difference between H0 and H0 - ) absolute value.

[0093] Figure 15B is a schematic diagram showing the structure of the film of this example. In this figure, the dots indicate layers whose thickness was varied to examine the effect of film thickness. Figure 15C is a graph showing the relationship between the applied magnetic field and the magnetization of the film for films with first magnetic layer: 60FeCo thicknesses of 1.5 nm, 2.4 nm, and 4.5 nm. As shown in the figure, the change in the film magnetization (Ms·t) varies depending on the film thickness of the first magnetic layer: 60FeCo.

[0094] In this example, films were fabricated with the first magnetic layer: 60FeCo having thicknesses of 1.4, 1.5, 1.6, 1.8, 2.0, 2.4, 2.8, 3.2, 3.6, 4.0, 4.5, 5.0, 6.0, and 7.0 nm. The relationship between the applied magnetic field and the magnetization of the first magnetic layer was measured for films with different 60FeCo thicknesses, and M0, ΔM0, Ms, Hex, and Hc were calculated for each film.

[0095] FIG. 15D is a graph showing the film thickness dependence of M0 / Ms for the first magnetic layer: 60FeCo. An ideal M0 / Ms is 1.0. A small M0 / Ms means that the squareness of the graph showing the relationship between the applied magnetic field and the magnetization amount of the first magnetic layer is poor, and the magnetization dispersion is large (see FIG. 15C). Therefore, when M0 / Ms is small, it is difficult to increase ΔMR. As shown in FIG. 15D, by making the film thickness of 60FeCo 1.6 mm or more, M0 / Ms becomes 0.8 or more, resulting in a film with a large ΔMR.

[0096] 15E and 15F are graphs showing the dependence of Hex and Hc on the thickness of the first magnetic layer, respectively. As shown in these figures, it was found that both Hex and Hc of the film change depending on the thickness of the 60FeCo film.

[0097] 15G is a graph showing the film thickness dependence of the ratio of ΔM0 to Hex / Hc and 2Ms on the first magnetic layer, and the respective values ​​are shown in Table 4. Note that in this figure and Table 4, the ratio of ΔM0 to 2Ms is expressed as a percentage, so the ΔM0 / 2Ms (%) shown in these figures and tables is the value of 100 × (ΔM0 / 2Ms). Hereinafter, the ratio of ΔM0 to 2Ms will be referred to as ΔM0 / 2Ms.

[0098]

[0099] If the Hex / Hc of the film is small, hysteresis is likely to occur in zero magnetic field, and the strong magnetic field resistance is deteriorated. Therefore, from the viewpoint of strong magnetic field resistance, a large Hex / Hc is preferable. Although the Hex / Hc is large for 60FeCo films with a film thickness of 1.5 nm or less, this is due to the deterioration of squareness in the graph showing the relationship between the applied magnetic field and the magnetization amount of the first magnetic layer, resulting in a small Hc, which is not practical. The Hex / Hc of the film increased when the 60FeCo film thickness was 1.8 nm or more, saturated around 3.2 nm, and tended to decrease when the film thickness was 4.5 nm or more.

[0100] If the ΔM0 / 2Ms of the film is large, hysteresis is likely to occur in zero magnetic field, and the resistance to strong magnetic fields deteriorates. Therefore, it is preferable that ΔM0 / 2Ms is close to zero. ΔM0 / 2Ms was stable at a low value of 1% or less when the thickness of the 60FeCo film was in the range of 1.6 to 4.5 nm, and tended to increase when the thickness exceeded 4.5 nm.

[0101] 15B, a magnetic field of 1 T was applied to the film of this example, and the resistance change rate ΔMR after the application of the strong magnetic field was measured. The ΔMR change rate was calculated using ΔMRa before the application of the 1 T magnetic field and ΔMRb after the application of the 1 T magnetic field according to the following formula (1): ΔMR change rate (%)=[(ΔMRa−ΔMRb) / ΔMRa]×100 (1)

[0102] FIG. 15H is a graph showing the dependence of ΔM0 / 2Ms and ΔMR change rate on the thickness of the first magnetic layer 60FeCo. As shown in FIG. 15H and Table 4, ΔM0 / 2Ms and ΔMR change rate change in substantially the same manner as the thickness of the first magnetic layer 60FeCo. This indicates that the magnetization dispersion of the first magnetic layer 60FeCo can be evaluated using ΔMR change rate instead of ΔM0 / 2Ms. The ΔMR change rate stabilized at a low value of 2% or less when the thickness of the 60FeCo film was in the range of 1.6 to 4.5 nm, and tended to increase when the film thickness exceeded 4.5 nm.

[0103] (Example 10: Magnetic detection device) On the lower electrode layer [Ta (3) / Cu (20) / Ta (3) / Cu (20) / Ta (35)], an underlayer: NiFeCr (4.2) / free magnetic layer: [86NiFe (9.0) / CoFeB (1.0) / 50CoFe (0.6)] / insulating barrier layer: MgO (2.0) / second magnetic layer: [first CoFe layer: 50CoFe (0.3) / crystal orientation reset The TMR film was manufactured by stacking the following layers in this order: first magnetic layer: CoFeB (0.7) / crystalline orientation promoting layer: 81.5NiFe (1.5) / second CoFe layer: 70CoFe (X) / non-magnetic intermediate layer: Ru (0.4) / first magnetic layer: 60FeCo (Y) / antiferromagnetic layer: IrMn (8.0) / protective layer: [Ru (5.0) / Ta (15.0) / Ru (5.0)].

[0104] Figure 16A is a schematic diagram showing the structure of the TMR film of this example. In this figure, ● indicates a layer whose thickness was changed to investigate the effect of film thickness, and ◯ indicates a layer whose thickness was changed to equalize the magnetization of the second magnetic layer, which changes with the film thickness of the layer. In this example, TMR films were fabricated with combinations of thickness X of the second CoFe layer (70CoFe film) in the second magnetic layer and thickness Y of the first magnetic layer (60FeCo film) of (X, Y) = (0.5, 2.0), (1.6, 3.0), and (2.7, 4.0), and a magnetic detection device was fabricated using these TMR films (see Figure 4).

[0105] 16B is a graph showing the relationship between the normalized bridge output of the magnetic detection device and the thickness X of the first magnetic layer and the thickness Y of the second CoFe layer. As shown in the figure, the larger the magnetization (Ms·t) of the first magnetic layer and the second magnetic layer, the smaller the plateau regions of the RH waveform and VH waveform, and the lower the resistance to strong magnetic fields. From this result, it can be said that a smaller film thickness of the first magnetic layer and the second magnetic layer is preferable.

[0106] From the results of the examples shown in Figures 15H and 16B, from the viewpoint of obtaining a tunneling magnetoresistive element and a magnetic detection device with excellent resistance to strong magnetic fields, the thickness of the first magnetic layer: 60FeCo film is preferably 1.6 to 4.5 nm. From the viewpoint of increasing the resistance to strong magnetic fields of the magnetoresistive element shown in Figure 15H, it is more preferable that it be 3.0 to 4.5 nm. Furthermore, from the viewpoint of increasing the resistance to strong magnetic fields in the normalized bridge output shown in Figure 16B, it can be said that the thickness of the first magnetic layer: 60FeCo film is more preferable that it be 1.6 to 3.2 nm.

[0107] According to the results of the above-mentioned examples, the thickness of the first magnetic layer: 60FeCo is preferably 1.6 to 4.5 nm from the viewpoint of obtaining a tunneling magnetoresistive film and a magnetic detection device having excellent resistance to strong magnetic fields. When the thickness of the first magnetic layer is set to 1.6 to 4.5 nm and the second magnetic layer is configured with [first CoFe layer / CoFeB / NiFe / second CoFe layer], and the thicknesses of the three layers constituting the second magnetic layer are set as the functional lower limit, the upper limit of the thickness that can be taken by the remaining layer is determined by the condition that the magnetization amounts (saturation magnetization amount Ms x layer thickness t) of the first magnetic layer and the second magnetic layer are equal.

[0108] The upper limit film thickness and optimum film thickness range of each layer constituting the second magnetic layer when the upper limit value of the first magnetic layer: 60FeCo is 4.5 nm is shown in the table below.

[0109] First magnetic layer: When the lower limit value of 60FeCo is 1.6 nm, the upper limit film thickness of each layer constituting the second magnetic layer is shown in the table below.

[0110] First magnetic layer: When the optimum value of 60FeCo is 3.0 nm, the upper limit film thickness of each layer constituting the second magnetic layer is shown in the table below.

[0111] (Example 11: Dependence of Hc on the CoFe Composition of the First Magnetic Layer) Figure 17A is a schematic diagram showing a structure in which a pinned magnetic layer is formed on an underlayer. In this figure, the dots indicate layers in which the Fe composition ratio was changed to investigate the effect of the Fe composition ratio of FeCo in the first magnetic layer of the pinned magnetic layer on the coercivity Hc. This makes it possible to determine the optimal composition range of Fe in the FeCo alloy of the first magnetic layer of the TMR film. The film was manufactured by stacking the underlayer: NiFeCr (4.2), non-magnetic material layer: Cu (4.0), non-magnetic intermediate layer: Ru (0.4), first magnetic layer: xFeCo (2.0), antiferromagnetic layer: IrMn (8.0), and protective layer: Ta (12.0) in this order.

[0112] In this example, films were manufactured in which the x (at.%) of Fe in the first magnetic layer: xFeCo was set to 0, 10, 20, 30, 40, 50, 60, 70, 80, 90, and 100. For each film, the relationship between the applied magnetic field and the coercive force (Ms·t) was measured to determine Hc (see FIG. 15A).

[0113] FIG. 17A is a schematic diagram showing the film configuration of this example. In the figure, the dots indicate layers whose composition ratios were changed to examine the effect of film thickness. FIG. 17B is a graph showing the relationship between the composition and Hc of the first magnetic layer. As shown in the figure, when the Fe composition ratio in FeCo is in the range of 40 to 80 at. %, Hc is 350 Oe or greater, and the squareness of the graph showing the relationship between the applied magnetic field and the magnetization of the first magnetic layer is improved. Therefore, it is preferable that the Fe composition ratio in the FeCo constituting the first magnetic layer is 40 to 80 at. %.

[0114] The tunneling magnetoresistive element of the present invention can be used in a magnetic detection device or the like that includes a plurality of magnetoresistive elements having pinned magnetic layers with different magnetization directions on the same substrate.

[0115] 10: TMR film (tunneling magnetoresistance effect element) 11: Underlayer 12: Free magnetic layer 13: Insulating barrier layer 14: Second magnetic layer 141: First CoFe layer 142: Crystal orientation reset layer 143: Crystal orientation promoting layer 144: Second CoFe layer 15: Non-magnetic intermediate layer 16: First magnetic layer 17: Antiferromagnetic layer 18: Protective layer 19: Fixed magnetic layer 40: Full bridge circuit 41: Power supply voltage Vdd 42a, 42b: Series circuit 43a, 43b: Midpoint terminal 44: Ground potential GND 50: Magnetic detection device

Claims

1. A top-pinned tunneling magnetoresistance effect element having a free magnetic layer, an insulating barrier layer, and a pinned magnetic layer stacked in this order, wherein the pinned magnetic layer has a second magnetic layer, a non-magnetic intermediate layer, and a first magnetic layer stacked in this order from the insulating barrier layer side, and has a self-pinned structure in which the pinned magnetization directions of the second magnetic layer and the first magnetic layer are antiparallel, wherein the second magnetic layer has a first CoFe layer, a CoFeB layer, a NiFe layer, and a second CoFe layer stacked in this order from the insulating barrier layer side, wherein the first magnetic layer is an FeCo layer, and the FeCo layer has a composition ratio of 40 to 80 at. % and a film thickness of 1.6 to 4.5 nm.

2. The tunneling magnetoresistive element according to claim 1, wherein the first CoFe layer has a thickness of 0.3 to 3.6 nm, the CoFeB layer has a thickness of 0.5 to 4.1 nm, the NiFe layer has a thickness of 0.5 to 8.1 nm, and the second CoFe layer has a thickness of 0.3 to 3.9 nm.

3. The Co composition ratio of the first CoFe layer is 20 to 80 at. %, and the CoFeB layer has a composition ratio of (Co 100-X Fe X ) 100-Y B Y 3. The tunneling magnetoresistive element according to claim 2, wherein X is 25 to 100 at. %, Y is 10 to 30 at. %, the Ni composition ratio of the NiFe layer is 40 to 100 at. %, and the Co composition ratio of the second CoFe layer is 60 to 100 at. %.

4. The first magnetic layer has a positive saturation magnetization Ms and a negative saturation magnetization Ms - The difference between Ms and Ms - ) for 2Ms, the magnetization amount M0 in zero magnetic field when changing from a saturation state on the negative side to a saturation state on the positive side, and the magnetization amount M0 in zero magnetic field when changing from a saturation state on the positive side to a saturation state on the positive side. - The difference between (M0-M0 - 2. The tunneling magnetoresistive element according to claim 1, wherein the ratio of ΔM0 where ΔM0 is 1% or less.

5. The tunneling magnetoresistive element according to claim 1, wherein the ΔMR change rate, expressed by the following formula (1), is 2% or less, where ΔMRa is the resistance change rate before application of a 1 T magnetic field and ΔMRb is the resistance change rate after application of a 1 T magnetic field: ΔMR change rate (%) = [(ΔMRa - ΔMRb) / ΔMRa] × 100 (1) 6. A magnetic detection device in which a plurality of tunneling magnetoresistive effect elements according to claim 1 are formed on the same substrate, and the plurality of tunneling magnetoresistive effect elements include those in which the fixed magnetic layers have different fixed magnetization directions.

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