Magnetoresistive elements, magnetic sensors, and magnetic memory

Abstract

The magnetoresistive element of this embodiment includes a first magnetic layer (11) and a second magnetic layer (13) stacked on a bottom layer (10), and a first non-magnetic layer (12) disposed between the first magnetic layer (11) and the second magnetic layer (13). The first non-magnetic layer (12) contains a fluorine-containing insulating material.

Description

Technical Field

[0001] This invention relates to a magnetoresistive element, a magnetic sensor, and a magnetic memory. Prior Technology

[0002] Magnetic tunneling junction (MTJ) devices exhibit a significant magnetoresistive effect at room temperature, making them suitable for use as memory elements in non-volatile magnetic memory or as high-sensitivity magnetic sensors. The basic structure of an MTJ device consists of a sandwich structure comprising two magnetic layers containing magnetic thin films, sandwiching a non-magnetic thin film (also known as a tunnel barrier layer) containing an insulator. The non-magnetic thin film is extremely thin, approximately several nanometers thick. Therefore, when a voltage is applied across the device, a tunneling current flows. However, the magnitude of this tunneling current depends on the relative magnetization angle of the two magnetic layers. This is known as the tunneling magnetoresistive (TMR) effect.

[0003] In magnetic memory, the magnetization of one magnetic layer (reference layer) is fixed, and the magnetization of another magnetic layer (recording layer) is controlled by an external field. Information ("0" or "1") is non-volatilely stored by overwriting the parallel and antiparallel states of the magnetization. Methods for controlling the external field direction of magnetization include, for example, using a current-magnetic field generated by passing current through external wiring, or directly passing current through the MTJ element to utilize the spin angular momentum transfer effect; or using voltage to control magnetic anisotropy, etc. When reading information, the TMR effect is used.

[0004] When realizing high-capacity magnetic memory, perpendicular magnetization type MTJ devices with the magnetic layer magnetized perpendicular to the direction can be used. This is because, for example, in writing methods utilizing the spin angular momentum transfer effect, a significant increase in writing energy can be avoided, allowing for a larger design of uniaxial magnetic anisotropy (perpendicular magnetic anisotropy) that stabilizes the parallelism and antiparallelism of the magnetization. However, since the materials used in existing MTJ devices need to balance perpendicular magnetic anisotropy and the TMR effect, material options are limited. It is considered that simply using commonly used cobalt-iron (CoFe) alloys for the magnetic layer and magnesium oxide (MgO) for the non-magnetic layer would be insufficient to ensure the perpendicular magnetic anisotropy suitable for ultra-Gbit-level high-capacity magnetic memory.

[0005] On the other hand, magnetic sensors are devices that convert external magnetic fields into electrical signals and detect them. They are widely used in magnetic recording media, such as magnetic heads, in automotive electrical equipment, and in industrial equipment as rotation, angle, current, position, and biomagnetic sensors. In particular, magnetic sensors using MTJ elements are characterized by higher sensitivity due to a larger change in resistance relative to changes in the magnetic field. In magnetic sensors, the relative angular change in magnetization of two magnetic layers caused by the magnitude of an externally applied magnetic field is electrically detected via the TMR effect.

[0006] The magnetic sensor uses the following MTJ element: The magnetization orientation of one of the two magnetic layers (reference layer) is fixed, and the easy magnetization axis of the other magnetic layer (hereinafter referred to as the magnetic field detection layer) is designed to be tilted 90 degrees relative to the magnetization of the reference layer. The magnetic field is detected by the change in element resistance caused by the tilting of the detection layer in response to an external magnetic field. For example, when the magnetization of the reference layer is fixed in one in-plane direction and a perpendicular magnetization film is used as the magnetic field detection layer, the strength of the in-plane magnetic field in a direction parallel to the reference layer can be detected. When the magnetization of the magnetic field detection layer saturates in the in-plane direction, no further resistance change occurs; therefore, it is important to ensure a large perpendicular magnetic anisotropy in the magnetic field detection layer to enable detection over a wider magnetic field region.

[0007] Furthermore, in order to obtain a magnetoresistive element with excellent characteristics, it is important to improve the characteristics of the tunnel barrier layer (for example, see Patent Document 1). In Patent Document 1, by further containing an additive element selected from fluorine (F), sulfur (S), hydrogen (H) and lithium (Li) in a non-magnetic layer (tunnel barrier layer) containing MgO, the additive element is used to compensate for defects or grain boundaries present in the tunnel barrier layer, thereby improving crystallinity and suppressing leakage current. Previous technical documents Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2020-155565 Summary of the Invention

[0009] [The problem the invention aims to solve]

[0010] This embodiment provides a magnetoresistive element, a magnetic sensor, and a magnetic memory with high vertical magnetic anisotropy and a high TMR ratio. [Technical means to solve the problem]

[0011] The magnetoresistive element of this embodiment includes: a first magnetic layer and a second magnetic layer deposited on a substrate, and a first non-magnetic layer disposed between the first magnetic layer and the second magnetic layer. The first non-magnetic layer comprises a fluorine-containing insulating material. Simple Explanation of the Diagram

[0012] Figure 1 is a cross-sectional view of the magnetoresistive element according to the first embodiment. Figure 2 is a cross-sectional view of the magnetoresistive element according to the second embodiment. Figure 3 is a cross-sectional view of the magnetoresistive element according to the third embodiment. Figure 4 is a cross-sectional view of the magnetoresistive element according to the fourth embodiment. Figure 5 is a cross-sectional view of the magnetoresistive element in the fifth embodiment. Figure 6 is a cross-sectional view of the magnetoresistive element according to the sixth embodiment. Figure 7 is a cross-sectional view of the magnetoresistive element in the seventh embodiment. Figure 8 is a cross-sectional view of the magnetoresistive element according to the eighth embodiment. Figure 9 is a cross-sectional view of the magnetoresistive element according to the ninth embodiment. Figure 10A is a schematic diagram of the component structure of Embodiment 1. Figure 10B is a diagram showing a comparative example of magnetic properties obtained by magneto-optical effect in Example 1. Figure 11A is a schematic diagram of the magnetoresistive element structure in Embodiment 2. Figure 11B is a graph showing the comparative example of magnetic properties obtained by magnetoresistance measurement in Example 2. Figure 11C is a comparative example of the element resistance and MR effect characteristics obtained by measuring the magnetoresistive effect in Example 2. Figure 12A is a schematic diagram of the component structure of Embodiment 3. Figure 12B is a diagram showing a comparative example of magnetic properties obtained by magneto-optical effect in Example 3. Figure 13A is a schematic diagram of the component structure of Embodiment 4. Figure 13B is a diagram showing the comparative example of magnetic properties obtained by magneto-optical effect in Example 4. Figure 14A shows an example of the magnetic sensor configuration in Embodiment 5. Figure 14B is a schematic diagram of the magnetization response of the magnetic field detection layer when a positive and negative magnetic field are applied. Figure 14C shows the magnetization response of the magnetic field detection layer when a positive and negative magnetic field are applied. Figure 14D shows the change in the resistance of a component relative to a magnetic field. Figure 15A is a schematic partial cross-sectional view and equivalent circuit diagram of the magnetic memory of Embodiment 6. Figure 15B is a schematic partial cross-sectional view and equivalent circuit diagram of the magnetic memory in Embodiment 6. Figure 16 is a schematic perspective view of the magnetic memory of Example 6. Implementation

[0013] The embodiments of the present invention will now be described in detail based on the drawings. Furthermore, in the following embodiments, repeated descriptions are omitted by labeling the same parts with the same symbols. Also, the present invention is not limited to the embodiments; the various values ​​and materials used in the embodiments are illustrative.

[0014] The magnetoresistive element of this embodiment is characterized by imparting a large vertical magnetic anisotropy and maintaining a high TMR ratio by introducing a fluorine-containing insulator into the non-magnetic layer that forms a tunnel barrier.

[0015] Figure 1 shows a cross-sectional view of the magnetoresistive element according to the first embodiment. The magnetoresistive element of the first embodiment has a laminated structure consisting of a bottom layer 10, a first magnetic layer 11, a first non-magnetic layer 12, and a second magnetic layer 13 in sequence. It is characterized by using a fluoride insulator in the first non-magnetic layer 12. It is also characterized by imparting a large perpendicular magnetic anisotropy at the interface between the first magnetic layer 11 and the first non-magnetic layer 12, and at the interface between the first non-magnetic layer 12 and the second magnetic layer 13.

[0016] Figure 2 shows a cross-sectional view of the magnetoresistive element according to the second embodiment. The magnetoresistive element of the second embodiment is characterized in that, in addition to the structure of the first embodiment, a second non-magnetic layer 14 is disposed on the first non-magnetic layer 12, thus having a stacked non-magnetic layer structure. The material of the second non-magnetic layer 14 can be an oxide insulator or a nitride insulator, in addition to a fluoride insulator. Similar to the first embodiment, the first non-magnetic layer 12 imparts a large perpendicular magnetic anisotropy to the first magnetic layer 11. The purpose of selecting the material of the second non-magnetic layer 14 is to: adjust the element's resistance value or enhance the TMR effect, adjust the relative permittivity of the non-magnetic layer, etc. Furthermore, the stacking order of the first non-magnetic layer 12 and the second non-magnetic layer 14 can also be reversed. In this case, a large perpendicular magnetic anisotropy is imparted to the interface on the side of the second magnetic layer 13.

[0017] Figure 3 shows a cross-sectional view of the magnetoresistive element according to the third embodiment. The magnetoresistive element of the third embodiment is constructed by inserting a first non-magnetic layer 12 between the second non-magnetic layer 14 and the second magnetic layer 13 of the second embodiment; the non-magnetic layer has a three-layer stacked structure. Both the first magnetic layer 11 and the second magnetic layer 13 are in contact with the first non-magnetic layer 12, which contains a fluoride insulator, thus imparting a greater perpendicular magnetic anisotropy. The material selection for the second non-magnetic layer 14 is the same as in the second embodiment.

[0018] Figure 4 shows a cross-sectional view of the magnetoresistive element according to the fourth embodiment. The magnetoresistive element of the fourth embodiment is constructed by disposing a third non-magnetic layer 15 on the second magnetic layer 13 of the first embodiment. The material of the third non-magnetic layer 15 can be any one of fluoride insulators, oxide insulators, and nitride insulators. Therefore, perpendicular magnetic anisotropy can also be imparted to the second magnetic layer 13 from the interface side between the second magnetic layer 13 and the third non-magnetic layer 15, thus further improving the perpendicular magnetic anisotropy of the second magnetic layer 13 compared to the first embodiment.

[0019] Figure 5 shows a cross-sectional view of the magnetoresistive element according to the fifth embodiment. The magnetoresistive element of the fifth embodiment is constructed by distributing a third non-magnetic layer 15 on the second magnetic layer 13 of the second embodiment. In the magnetoresistive element of the fifth embodiment, when the perpendicular magnetic anisotropy of the second magnetic layer 13 is reduced due to the introduction of the second non-magnetic layer 14 for the same reason as in the second embodiment, perpendicular magnetic anisotropy can be imparted at the interface between the second magnetic layer 13 and the third non-magnetic layer 15. Furthermore, similarly to the second embodiment, the stacking order of the first non-magnetic layer 12 and the second non-magnetic layer 14 can also be reversed. In this case, the perpendicular magnetic anisotropy on the second magnetic layer 13 side is enhanced by the first non-magnetic layer 12.

[0020] Figure 6 shows a cross-sectional view of the magnetoresistive element according to the sixth embodiment. The magnetoresistive element of the sixth embodiment is constructed by disposing a third non-magnetic layer 15 on the second magnetic layer 13 of the third embodiment. The vertical magnetic anisotropy of the second magnetic layer 13, which is enhanced at the interface with the first non-magnetic layer 12 disposed on the upper side within the non-magnetic layer described below, can also be further enhanced by the interface with the third non-magnetic layer 15 side. The non-magnetic layer includes a three-layer stacked structure of the first non-magnetic layer 12, the second non-magnetic layer 14, and the first non-magnetic layer 12.

[0021] Figure 7 shows a cross-sectional view of the magnetoresistive element according to the seventh embodiment. The magnetoresistive element of the seventh embodiment is constructed by placing a third magnetic layer 16 on the third non-magnetic layer 15 of embodiment 4, and is a magnetoresistive element structure having two tunnel barrier layers, the first non-magnetic layer 12 and the third non-magnetic layer 15, separated by the second magnetic layer 13. The magnetoresistive element of the seventh embodiment can also simultaneously utilize the TMR effect between the first magnetic layer 11 and the second magnetic layer 13 of the first non-magnetic layer 12, and the TMR effect between the second magnetic layer 13 and the third magnetic layer 16 of the third non-magnetic layer 15. In this way, the magnetoresistive element of the seventh embodiment can achieve a design that takes into account the following effects: reducing the bias voltage dependence of the TMR effect, enhancing the perpendicular magnetic anisotropy of one non-magnetic layer, and enhancing the TMR effect of the other non-magnetic layer.

[0022] Figure 8 shows a cross-sectional view of the magnetoresistive element of the eighth embodiment. The magnetoresistive element of the eighth embodiment is constructed by distributing a third magnetic layer 16 on the third non-magnetic layer 15 of embodiment 5. It is a magnetoresistive element structure with two tunnel barrier layers, similar to the seventh embodiment. The lower non-magnetic layer is a stacked structure of the first non-magnetic layer 12 and the second non-magnetic layer 14.

[0023] In the magnetoresistive element of the eighth embodiment, when the perpendicular magnetic anisotropy of the second magnetic layer 13 is reduced due to the introduction of the second non-magnetic layer 14 for the same reason as in the second embodiment, the perpendicular magnetic anisotropy can be enhanced at the interface between the second magnetic layer 13 and the third non-magnetic layer 15. Furthermore, the magnetoresistive element of the eighth embodiment can also utilize the TMR effect between the second magnetic layer 13 and the third magnetic layer 16 that separates the third non-magnetic layer 15. Therefore, similar to the seventh embodiment, the magnetoresistive element of the eighth embodiment can achieve a design that takes into account the following effects: reducing the bias voltage dependence of the TMR effect, enhancing the perpendicular magnetic anisotropy of one non-magnetic layer, and enhancing the TMR effect of the other non-magnetic layer. Moreover, the stacked structure of the first non-magnetic layer 12 / the second non-magnetic layer 14 and the arrangement of the third non-magnetic layer 15 can also be reversed.

[0024] Figure 9 shows a cross-sectional view of the magnetoresistive element according to the ninth embodiment. The magnetoresistive element of the ninth embodiment is constructed by disposing a third magnetic layer 16 on the third non-magnetic layer 15 of the sixth embodiment. It is a magnetoresistive element structure with two tunnel barrier layers, similar to the seventh and eighth embodiments. Its lower non-magnetic layer is a three-layer structure consisting of a first non-magnetic layer 12, a second non-magnetic layer 14, and a third non-magnetic layer 12. In the magnetoresistive element of the ninth embodiment, the vertical magnetic anisotropy of the second magnetic layer 13, which is enhanced at the interface with the first non-magnetic layer 12 disposed on the upper side within the non-magnetic layer, can also be further enhanced by the interface with the third non-magnetic layer 15. The non-magnetic layer includes a three-layer stacked structure consisting of a first non-magnetic layer 12, a second non-magnetic layer 14, and a third non-magnetic layer 12. Furthermore, in addition to utilizing the TMR effect between the first magnetic layer 11 and the second magnetic layer 13 of the first non-magnetic layer 12, the second non-magnetic layer 14, and the first magnetic layer 13 of the first non-magnetic layer 12, the magnetoresistive element of the ninth embodiment can also utilize the TMR effect between the second magnetic layer 13 and the third magnetic layer 16 of the third non-magnetic layer 15. Therefore, similar to the seventh and eighth embodiments, the magnetoresistive element of the ninth embodiment can achieve a design that considers the following effects: reducing the bias voltage dependence of the TMR effect, enhancing the perpendicular magnetic anisotropy of one non-magnetic layer, and enhancing the TMR effect of the other non-magnetic layer. Furthermore, the stacked structure of the first non-magnetic layer 12 / the second non-magnetic layer 14 / the first non-magnetic layer 12 and the arrangement of the third non-magnetic layer 15 can also be reversed.

[0025] Furthermore, in Patent Document 1, by further containing an additive element selected from fluorine (F), sulfur (S), hydrogen (H), and lithium (Li) in a non-magnetic layer (tunnel barrier layer) containing MgO, the additive element is used to compensate for defects or grain boundaries present in the tunnel barrier layer, thereby improving crystallinity and suppressing leakage current. The method of containing one or more additive elements in the tunnel barrier layer (MgO tunnel barrier layer) disclosed in Patent Document 1 is as follows.

[0026] In method 1, an MgO target with added elements is used, and an MgO layer with added elements is deposited using sputtering or vapor deposition. In method 2, after depositing an Mg layer with added elements using an Mg target, or during the deposition process, the substrate is exposed to an oxygen atmosphere. In method 3, a wafer with added elements is attached to an MgO target, and an MgO layer with added elements is deposited using sputtering or vapor deposition.

[0027] In the MgO tunnel barrier layer containing added elements obtained by the above method, the added elements are randomly distributed in the MgO layer.

[0028] In contrast, in this invention, the fluoride insulating system forms a thin film layer of non-magnetic layer, the morphology of which is fundamentally different from that of Patent Document 1, which randomly adds elements selected from fluorine (F), sulfur (S), hydrogen (H), and lithium (Li) to the non-magnetic layer. Furthermore, the greater perpendicular magnetic anisotropy obtained by this invention is induced by the presence of the interface between the magnetic layer and the non-magnetic layer containing the fluoride insulator. In the random addition method of Patent Document 1, since there is no interface between the magnetic layer and the non-magnetic layer containing the fluoride insulator, a greater perpendicular magnetic anisotropy cannot be exhibited.

[0029] Next, the materials of each component constituting the magnetoresistive element in embodiments 1 to 9 will be described.

[0030] [First magnetic layer 11, second magnetic layer 13, and third magnetic layer 16] The first magnetic layer 11, the second magnetic layer 13, and the third magnetic layer 16 may be layers containing magnetic elements such as Fe, Co, Ni, Mn, Nd, Sm, Tb, or alloys thereof. Alternatively, a multilayer magnetic layer comprising the aforementioned magnetic elements, or a multilayer magnetic layer comprising the aforementioned magnetic elements and at least one of Pt, Pd, Ir, Ru, Re, Rh, Os, Au, Ag, Cu, Re, W, Mo, Bi, V, Ta, Cr, Ti, Zn, Si, Al, and Mg, may be used. The first magnetic layer 11, the second magnetic layer 13, and the third magnetic layer 16 are in most cases crystalline layers that match the crystal lattice of the first non-magnetic layer 12, the second non-magnetic layer 14, and the third non-magnetic layer 15, and a bcc(001) structure is commonly used. However, they may also be formed as amorphous layers during film formation and then crystallized through a solid-state epitaxial process via heat treatment.

[0031] [First non-magnetic layer 12] A fluorine-containing insulator is used in the first non-magnetic layer 12. Specifically, the following compounds are used: LiF, NaF, AgF, CsF, KF, RbF, CuF₂, CoF₂, MgF₂, MnF₂, NiF₂, PdF₂, ZnF₂, CaF₂, SrF₂, PbF₂, BaF₂, CdF₂, EuF₂, AlF₃, BiF₃, InF₃, CrF₃, FeF₃, GaF₃, RhF₃, SbF₃, AuF₃, HfF₄, SnF₄, ZrF₄, TiF₄, NbF₅, TaF₅, WF₆, CeOF, HoOF, LaOF, NdOF, PrOF, FeF₃, MoF₃, NdF₃, TaF₃, NbOF₂, TaO₂F, TiO₂ At least one fluoride insulator from the group consisting of 2F. LiF, which has better lattice matching than FeCo alloys with bcc structure, which are commonly used in MTJ elements, is particularly preferred.

[0032] [Second non-magnetic layer 14 and third non-magnetic layer 15] In the second nonmagnetic layer 14 and the third nonmagnetic layer 15, in addition to using the same fluoride insulator as the first nonmagnetic layer 12, oxides of at least one element selected from the group consisting of Mg, Al, Ti, Si, Zn, Zr, Hf, Ta, Bi, Cr, Ga, La, Gd, Sr, and Ba, or nitrides selected from the group consisting of at least one element selected from the group consisting of Mg, Al, Ti, Si, Zn, Zr, Hf, Ta, Bi, Cr, Ga, La, Gd, Sr, and Ba, are used. Particularly preferred are MgO, MgAl₂O₄, Al₂O₃, etc., which have good lattice matching with LiF and can achieve a high TMR ratio.

[0033] [Bottom 10] In the bottom layer 10, for example, layers containing noble metals or transition metal elements such as Cr, Ta, Ru, Au, Ag, Cu, Al, Ti, V, Mo, Zr, Hf, Re, W, Pt, Pd, Ir, and Rh, or their stacked structures, can be used. Especially when the first magnetic layer 11 uses a CoFe alloy thin film with a bct structure, using Ir, Rh, Pd, Pt, and alloys containing them as the material of the bottom layer 10 is more effective. Furthermore, when the first magnetic layer 11 is used as a magnetization fixing layer, a bottom layer 10 containing antiferromagnetic alloys such as IrMn or PrMn in a stacked structure can be used. Furthermore, the bottom layer 10 can also be used as a lower electrode layer.

[0034] The various layers described above can be fabricated using physical vapor deposition (PVD), such as sputtering, ion beam deposition, and vacuum evaporation, or chemical vapor deposition (CVD), such as atomic layer deposition (ALD). Furthermore, the patterning of these layers can be performed using reactive ion etching (RIE) or ion polishing. Preferably, the various layers are formed continuously in a vacuum apparatus, and preferably patterned thereafter.

[0035] The following describes an example based on the experimental results.

[0036] [Example 1] As Example 1, as shown in FIG10A, a multilayer film structure was fabricated on an MgO (001) substrate. In this multilayer film structure, Cr (30 nm) was used in the bottom layer 10, Fe (0.8 nm) was used in the first magnetic layer 11, LiF (0-0.4 nm) was used in the first non-magnetic layer 12, MgO (2.4 nm) was used in the second non-magnetic layer 14, and indium tin oxide (20 nm) (hereinafter referred to as ITO) was used as a transparent conductive oxide in the upper electrode. A second magnetic layer 13 was disposed in the magnetoresistive element instead of the ITO layer. However, in this embodiment, in order to evaluate the effect of the insertion of the LiF layer on the magnetic properties of the Fe layer, a non-magnetic ITO electrode was used. Cr, Fe, LiF, and MgO are all (001) aligned single crystal films. In order to compare the film thickness dependence of LiF, a multilayer film structure with LiF film thickness varying in the range of 0 nm to 0.4 nm was fabricated on the same substrate. Except for the ITO film, all other layers were formed using molecular beam epitaxy, while the ITO film was formed by sputtering. The Cr layer was formed at 200°C and then heat-treated at 800°C for 10 minutes. The Fe layer was formed at 150°C and then heat-treated at 250°C for 10 minutes. The non-magnetic LiF and MgO layers were formed at room temperature and then heat-treated at 350°C for 10 minutes. The ITO top electrode was formed at room temperature.

[0037] Figure 10B shows the LiF film thickness dependence of the magnetic properties of the Fe layer, evaluated using the magneto-optical effect when a magnetic field is applied perpendicularly to the film surface. The horizontal axis in Figure 10B represents the magnitude of the magnetic field applied perpendicularly to the film surface from the outside. The unit of intensity on the horizontal axis is kOe. 1 Oe corresponds to (1 / 4π) × 10³ A / m. The vertical axis represents the polarization angle of the reflected light from a laser irradiated from above, i.e., the Kerr rotation angle (arbitrary unit). Without LiF insertion, even with a magnetic field of 4 kOe or more, magnetization in the perpendicular direction does not saturate, resulting in an in-plane magnetized film. On the other hand, with the insertion of 0.1 nm of LiF, magnetization saturates in the perpendicular direction in a magnetic field of approximately 2 kOe. Furthermore, with the insertion of 0.2 nm of LiF, the Fe layer becomes a vertically magnetized film with the perpendicular direction as its easy magnetization axis. As can be seen from the comparison, by using a fluoride insulator in the first non-magnetic layer 12, the perpendicular magnetic anisotropy of the first magnetic layer 11 can be enhanced. The thickness of the first non-magnetic layer 12 is preferably 0.1 nm or more, and more preferably 0.2 nm or more.

[0038] [Example 2] As an example 2, as shown in FIG11A, a magnetoresistive element was fabricated on an MgO(001) substrate. In this magnetoresistive element, Cr (30 nm) was used in the bottom layer 10, a multilayer magnetic layer comprising Fe (0.64 nm) / Ir (0.06 nm) / Co 80Fe 2O (0.1 nm) was used in the first magnetic layer 11, LiF (0-0.4 nm) was used in the first non-magnetic layer 12, MgO (2.4 nm) was used in the second non-magnetic layer 14, and Fe (10 nm) was used in the second magnetic layer 13. To compare the thickness dependence of the LiF film in the first non-magnetic layer 12, the LiF film thickness was varied within the range of 0 nm to 0.4 nm. These films were formed by molecular beam epitaxy. After the Cr layer was formed at 200°C, it was heat-treated at 800°C for 10 minutes. The Fe / Ir / Co 80Fe 20 laminated structure was deposited at 150°C and then heat-treated at 250°C for 10 minutes. Since this laminated structure responds to a magnetic field as a single magnetic thin film, it is uniformly considered as the first magnetic layer 11. The non-magnetic LiF and MgO laminates were deposited at room temperature and then heat-treated at 330°C for 10 minutes. The upper Fe electrode was deposited at 200°C and then heat-treated at 250°C for 10 minutes. Cr, the Fe / Ir / Co 80Fe 20 laminate, LiF, MgO, and the upper Fe layer are all (001) aligned single-crystal films.

[0039] Figure 11B shows the LiF insertion thickness dependence of the standardized TMR curve when an in-plane magnetic field is applied. Typically, in magnetoresistive elements for magnetic memory, both the first magnetic layer 11 and the second magnetic layer 13 use plane-perpendicular magnetization films. However, in this experiment, to evaluate the LiF layer insertion thickness dependence for the perpendicular magnetic anisotropy of the Fe layer, as shown in the schematic diagram of Figure 11A, the lower Fe layer of the first magnetic layer 11 is used as a plane-perpendicular magnetization film, and the upper Fe layer of the second magnetic layer 13 is used as an in-plane magnetization film. In this case, if an in-plane magnetic field is applied, the magnetization of the upper Fe layer remains parallel to the in-plane direction; only the magnetization direction of the lower Fe / Ir / Co 80Fe 20 layer changes from the plane-perpendicular direction to the in-plane direction. The resistance is lowest when the two Fe layers are parallel. Since the magnetic field strength required to generate this parallel magnetization state (called the anisotropic magnetic field) reflects the magnitude of the perpendicular magnetic anisotropy of the lower Fe layer, the effect of LiF insertion on perpendicular magnetic anisotropy can be evaluated by comparing the magnitudes of the anisotropic magnetic field. The unit of strength on the horizontal axis is kOe. 1 Oe corresponds to (1 / 4π) × 10³ A / m. The vertical axis normalizes the resistance to 1 under zero magnetic field and the resistance to 0 under an in-plane magnetic field of 16 kOe (in arbitrary units). As shown in Figure 11B, the anisotropic magnetic field of the lower Fe / Ir / Co 80Fe 20 layer is approximately 6 kOe when no LiF is inserted or when 0.06 nm of LiF is inserted. In contrast, this increases to approximately 8 kOe when 0.14 nm of LiF is inserted, and to approximately 10 kOe when 0.22 nm of LiF is inserted, indicating an increase in perpendicular magnetic anisotropy. Furthermore, it is evident that increasing the LiF thickness to 0.3 nm yields approximately the same result as increasing it to 0.22 nm. By covering the surface of the lower Fe / Ir / Co 80Fe 20 layer with LiF half-units (LiF has a lattice constant of approximately 0.4 nm) or more, the aforementioned increase in perpendicular magnetic anisotropy can be sufficiently achieved. According to this embodiment, the thickness of the first non-magnetic layer 12 can preferably be 0.1 nm or more, and more preferably 0.2 nm or more.

[0040] Figure 11 shows the dependence of the resistance and TMR ratio of the C-series element on the LiF insertion layer thickness. The horizontal axis represents the LiF insertion layer thickness, the left vertical axis represents the element resistance (white circles in the graph), and the right vertical axis represents the TMR ratio (black dots in the graph), with units of nm, kΩ, and %. Here, in the magnetoresistive element used in this embodiment, the magnetization of the magnetic layer in zero magnetic field is configured to 90 degrees, so it is the TMR ratio between the parallel magnetization state and the 90-degree magnetization state. It is about half of the TMR ratio when using the usual parallel-antiparallel resistance variation, so the right vertical axis is half the TMR ratio. It can be seen that the element resistance increases exponentially with respect to LiF insertion, and the LiF film acts as a tunnel barrier layer. Furthermore, regarding the TMR ratio, it shows a roughly constant value up to about 0.2 nm of LiF thickness, and increases in the region of film thickness above that. This indicates that in LiF films with half-unit or larger thicknesses, the same TMR effect obtained through the coherent tunneling mechanism as MgO can be achieved, demonstrating that LiF insertion is also an effective method for obtaining a larger TMR effect. That is, from the perspective of magnetoresistance characteristics, the thickness of the first nonmagnetic layer 12 can be inserted by more than 0.2 nm.

[0041] [Example 3] As in Example 3, as shown in FIG12A, a multilayer film structure was fabricated on a Si substrate with an attached thermal oxide film. In this multilayer film structure, Ta (5 nm) was used as the bottom layer 10, Fe 80B 20 (1.2 nm) was used as the first magnetic layer 11, LiF (0-0.4 nm) was used in the first non-magnetic layer 12, MgO (2.3 nm) was used in the second non-magnetic layer 14, and ITO (20 nm) was used in the top electrode. Similar to Example 1, an ITO thin film was used in the top electrode to evaluate the LiF insertion effect on the Fe 80B 20 layer. To compare the film thickness dependence of LiF, a multilayer film structure with LiF film thickness varying in the range of 0 nm to 0.4 nm was fabricated on the same substrate. The Ta, Fe 80B 20, and ITO layers were formed by sputtering, and the LiF and MgO layers were formed by molecular beam epitaxy. After forming a multilayer film of Ta to MgO at room temperature, it was heat-treated at 250°C for 10 minutes. The upper electrode of ITO was formed at room temperature. The Fe 80B 20-layer film had an amorphous structure during film formation, and after heat treatment, it partially acquired a bcc structure by solid-state epitaxy.

[0042] Figure 12B shows the LiF film thickness dependence of the magnetic properties of the Fe 80B 20 layer, evaluated using the magneto-optical effect when a magnetic field is applied perpendicularly to the film surface. The horizontal axis is expressed in kOe. 1 Oe corresponds to (1 / 4π) × 10³ A / m. The vertical axis represents the Kerr rotation angle (arbitrary unit). Perpendicularly magnetized films were obtained in structures with no LiF, with 0.2 nm of LiF inserted, and with 0.4 nm of LiF inserted. It can be seen that the greater the thickness of the LiF-inserted film, the greater the magnetic retention force and the greater the perpendicular magnetic anisotropy. Furthermore, the saturation Kerr rotation angle intensity of the Fe 80B 20 layer remains almost unchanged, without any effect such as a decrease in saturation magnetization due to LiF insertion. As can also be seen from this embodiment, the thickness of the first non-magnetic layer 12 is preferably 0.2 nm or more.

[0043] [Example 4] As in Example 4, as shown in FIG13A, the following multilayer structure was fabricated on an MgO(001) substrate. In this multilayer structure, a Cr (20 nm) / Pd (20 nm) / Ir (10 nm) multilayer structure was used as the bottom layer 10. Co 50Fe 50 (1.4 nm) was used in the first magnetic layer 11, a fluoride insulator (X nm) was used in the first non-magnetic layer 12, MgO ((2.8-X) nm) was used in the second non-magnetic layer 14, and ITO (20 nm) was used in the top electrode. The Co 50Fe 50 layer has a tetragonal (bct) structure due to the lattice strain from the Ir bottom layer side. As fluoride insulators (labeled as Fluoride in the figure), LiF, MgF2, and CaF2 were tried. Regarding the insertion layer thickness of each fluoride insulator, a film thickness equivalent to half a unit thickness of each material was inserted. Specifically, 0.2 nm of LiF, 0.23 nm of MgF₂, and 0.27 nm of CaF₂ were inserted. The MgO film on top was designed as a non-magnetic layer 12 / non-magnetic layer 14 stacked structure with a total film thickness of 2.8 nm. That is, it was MgO (2.6 nm) in LiF, MgO (0.257 nm) in MgF₂, and MgO (0.253 nm) in CaF₂. Except for the ITO film, all other layers were formed by molecular beam epitaxy, and the ITO film was formed by sputtering.

[0044] Figure 13B shows the dependence of the inserted fluoride material on the magnetic properties of the bct-Co 50Fe 50 layer obtained by evaluating the magneto-optical effect when a magnetic field is applied perpendicularly to the film surface. The horizontal axis is in kOe. 1 Oe corresponds to (1 / 4π) × 10³ A / m. The vertical axis is the Kerr rotation angle (arbitrary unit). In the case where no fluoride insulating film is inserted, i.e., in direct contact with MgO, the bct-Co 50Fe 50 layer is an in-plane magnetized film, requiring a magnetic field of about 4 kOe to magnetize it in the perpendicular direction. On the other hand, even when any of the fluoride insulators, such as LiF, MgF₂, or CaF₂, is inserted as a half-unit, it is a perpendicularly magnetized film with the perpendicular direction as the easy magnetization axis. Thus, it can be seen that, not limited to LiF, various fluoride insulators can achieve the effect of increasing perpendicular magnetic anisotropy. At this point, the thickness of the first non-magnetic layer 12 is preferably greater than about 0.2 nm, which is equivalent to the insertion of a half-unit.

[0045] Hereinafter, embodiments of a magnetic device having the magnetoresistive element described in Examples 1 to 4 will be described.

[0046] [Example 5] Example 5 relates to a magnetic device incorporating the magnetoresistive element described in Examples 1-4, specifically to a magnetic sensor. Figure 14A shows an example of the configuration of the magnetic sensor of the present invention. A first magnetic layer 11 is used as a magnetic field detection layer, and a second magnetic layer 13 is used as a reference layer for fixing the magnetization direction in one in-plane direction. If the magnetization direction of the first magnetic layer 11 changes according to an external magnetic field, the element resistance changes. This change is detected by a resistance detection unit. For example, when a magnetic field is applied to the right (defined as a positive magnetic field) as shown in Figure 14B, the relative angle of magnetization is close to parallel, thus the element resistance decreases. On the other hand, when a magnetic field is applied to the left (defined as a negative magnetic field) as shown in Figure 14C, the relative angle of magnetization is close to antiparallel, thus the element resistance increases. The change in element resistance relative to the magnetic field is shown in Figure 14D. Before reaching the region of the anisotropic magnetic field of the first magnetic layer 11, the resistance changes linearly, and the magnetic field can be detected in this region. That is, the greater the anisotropic magnetic field, the greater the range of detectable magnetic fields can be ensured. In this invention, by utilizing the first non-magnetic layer 12, the first magnetic layer 11 can be endowed with a greater perpendicular magnetic anisotropy, thus providing a magnetic sensor that can detect magnetic fields over a wide area.

[0047] [Example 6] Example 6 relates to a magnetic device having the magnetoresistive element described in Examples 1-4, specifically to a magnetic memory. Figure 15A shows a schematic partial cross-sectional view of the magnetic memory of the present invention, Figure 15B shows an equivalent circuit diagram, and Figure 16 shows a schematic perspective view. The magnetoresistive element 100 of this embodiment has a stacked structure consisting of a bottom layer 10, a first magnetic layer 11, a first non-magnetic layer 12, and a second magnetic layer 13 stacked sequentially. A selection transistor TR, including a field-effect transistor, is disposed below the magnetoresistive element 100.

[0048] Specifically, the device includes a selectable transistor TR formed on a silicon semiconductor substrate 60 and a first interlayer insulating layer 67 covering the selectable transistor TR, and a first wiring 41 is formed on the first interlayer insulating layer 67. The first wiring 41 is electrically connected to a source / drain region 64A of the selectable transistor TR via a connection hole (or connection hole and bonding pad or lower wiring) 65 provided in the first interlayer insulating layer 67.

[0049] The second interlayer insulation layer 68 covers the first interlayer insulation layer 67 and the first wiring 41, and an insulating material layer 51 surrounding the magnetoresistive element 100 and the capping layer 34 is formed on the second interlayer insulation layer 68. The lower part of the magnetoresistive element 100 is electrically connected to another source / drain region 64B of the selector transistor TR through a connection hole 66 provided in the first interlayer insulation layer 67 and the second interlayer insulation layer 68.

[0050] The second wiring 42 is formed on the insulating material layer 51, and the upper part of the magnetoresistive element 100 is electrically connected to the second wiring 42 via the capping layer 34. The selector transistor TR has a gate electrode 61, a gate oxide film 62, a channel forming region 63, and source / drain regions 64A and 64B. As described above, a source / drain region 64A and the first wiring 41 are connected to the first wiring (sensing line) 41 formed on the first interlayer insulating layer 67 via a connection hole 65.

[0051] Furthermore, another source / drain region 64B is connected to the magnetoresistive element 100 via a connection hole 66. The gate electrode 61 also functions as a so-called word line or address line. Moreover, the projected image of the extension direction of the second wiring (bit line) 42 is orthogonal to the projected image of the extension direction of the gate electrode 61, and parallel to the projected image of the extension direction of the first wiring 41. However, in FIG15A, for the sake of simplifying the diagram, the extension directions of the gate electrode 61, the first wiring 41, and the second wiring 42 are different from those shown.

[0052] The following is a summary description of the manufacturing method of the magnetic memory according to Example 6. First, based on a known method, a device separation region is formed on a silicon semiconductor substrate 60, and a selection transistor TR comprising a gate oxide film 62, a gate electrode 61, and source / drain regions 64A and 64B is formed on a portion of the silicon semiconductor substrate 60 surrounded by the device separation region. The portion of the silicon semiconductor substrate 60 located between the source / drain regions 64A and 64B corresponds to a channel formation region 63.

[0053] Next, a first interlayer insulating layer 67 is formed, and a connection hole 65 is formed on a portion of the first interlayer insulating layer 67 above a source / drain region 64A. Then, a first wiring 41 is formed on the first interlayer insulating layer 67. Next, a second interlayer insulating layer 68 is formed over the entire surface, and a connection hole 66 is formed on portions of the first interlayer insulating layer 67 and the second interlayer insulating layer 68 above another source / drain region 64B. This allows for the formation of a selector transistor TR covered by the first interlayer insulating layer 67 and the second interlayer insulating layer 68.

[0054] Then, a continuous film is formed on the entire surface, consisting of a bottom layer 10, a first magnetic layer 11, a first non-magnetic layer 12, a second magnetic layer 13, and a capping layer 34. Subsequently, for example, ion beam etching (IBE) is used to etch the capping layer 34, the second magnetic layer 13, the first non-magnetic layer 12, the first magnetic layer 11, and the bottom layer 10. The bottom layer 10 is connected to the connecting hole 66.

[0055] Next, an insulating material layer 51 is formed on the entire surface. By performing a planarization process on the insulating material layer 51, the top surface of the insulating material layer 51 is made flush with the top surface of the capping layer 34. Then, a second wiring 42 connected to the capping layer 34 is formed on the insulating material layer 51. In this way, a magnetic memory with the structure shown in FIG15A can be obtained. Thus, a general MOS (Metal Oxide Semiconductor) manufacturing process can be applied in the manufacturing of the magnetic memory of Embodiment 6, and it can be used as a general-purpose memory.

[0056] As described above, the magnetoresistive element, magnetic memory, and magnetic sensor of the present invention have higher perpendicular magnetic anisotropy compared to previous structures, thus ensuring higher thermal stability at room temperature and providing a magnetic device with fewer operational errors and higher operational tolerance. Furthermore, the effects described in this specification are merely examples and not limitations, and additional effects may also be present.

[0057] The present invention has been described above based on preferred embodiments, but the invention is not limited to these embodiments and can be implemented in various other ways. Various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. Furthermore, the various layered structures and materials used in the embodiments are merely examples and can be appropriately modified.

[0058] Furthermore, this technology can also be configured as described below. (1) A magnetoresistive element is characterized by comprising a first magnetic layer, a second magnetic layer, and a first non-magnetic layer disposed between the first magnetic layer and the second magnetic layer, all deposited on a bottom layer. The first non-magnetic layer 12 mentioned above contains a fluorine-containing insulating material. (2) As described in (1) above, the magnetoresistive element, in which The aforementioned first non-magnetic layer contains an insulating material containing fluorine, oxygen, or nitrogen. (3) The magnetoresistive element described in (1) or (2) above has a second non-magnetic layer between the first non-magnetic layer and the second magnetic layer, and The second nonmagnetic layer described above has a nonmagnetic layer comprising a laminated structure using a fluoride insulator, an oxide insulator, or a nitride insulator. (4) As described in any of (1) to (3) above, the magnetoresistive element, in which A vertically magnetized film is used in either the first magnetic layer or the second magnetic layer, or in either the first magnetic layer or the second magnetic layer. (5) As described in any of (1) to (3) above, the magnetoresistive element, in which The first non-magnetic layer mentioned above includes LiF, NaF, AgF, CsF, KF, RbF, CuF₂, CoF₂, MgF₂, MnF₂, NiF₂, PdF₂, ZnF₂, CaF₂, SrF₂, PbF₂, BaF₂, CdF₂, EuF₂, AlF₃, BiF₃, InF₃, CrF₃, FeF₃, GaF₃, RhF₃, SbF₃, AuF₃, HfF₄, SnF₄, ZrF₄, TiF₄, NbF₅, TaF₅, WF₆, CeOF, HoOF, LaOF, NdOF, PrOF, FeF₃, MoF₃, NdF₃, TaF₃, NbOF₂, and TaO₂. At least one of the fluorides 2F and TiO2F. (6) As described in (3) above, among which The first non-magnetic layer and the second non-magnetic layer 14 mentioned above comprise: LiF, NaF, AgF, CsF, KF, RbF, CuF 2, CoF 2, MgF 2, MnF 2, NiF 2, PdF 2, ZnF 2, CaF 2, SrF 2, PbF 2, BaF 2, CdF 2, EuF 2, AlF 3, BiF 3, InF 3, CrF 3, FeF 3. GaF 3, RhF 3, SbF 3, AuF 3, HfF 4, SnF 4, ZrF 4, TiF 4, NbF 5, TaF 5, WF 6, CeOF, HoOF, LaOF, NdOF, PrOF, FeF 3, MoF 3, NdF 3, TaF 3, NbOF 2, TaO 2F and TiO 2F is at least one of the fluorides; or an oxide containing at least one of Mg, Al, Ti, Si, Zn, Zr, Hf, Ta, Bi, Cr, Ga, La, Gd, Sr, and Ba; or a nitride containing at least one of Mg, Al, Ti, Si, Zn, Zr, Hf, Ta, Bi, Cr, Ga, La, Gd, Sr, and Ba. (7) As described in any of (1) to (3) above, the magnetoresistive element, in which The first non-magnetic layer mentioned above contains LiF. (8) As described in (3) above, among which The laminated structure of the first non-magnetic layer and the second non-magnetic layer uses a laminated structure of fluoride and MgO. (9) The magnetoresistive element described in any of (1) to (3) above has a third non-magnetic layer 15 on the second magnetic layer 13, and The third non-magnetic layer 15 mentioned above includes: LiF, NaF, AgF, CsF, KF, RbF, CuF 2, CoF 2, MgF 2, MnF 2, NiF 2, PdF 2, ZnF 2, CaF 2, SrF 2, PbF 2, BaF 2, CdF 2, EuF 2, AlF 3, BiF 3, InF 3, CrF 3, FeF 3. GaF 3, RhF 3, SbF 3, AuF 3, HfF 4, SnF 4, ZrF 4, TiF 4, NbF 5, TaF 5, WF 6, CeOF, HoOF, LaOF, NdOF, PrOF, FeF 3, MoF 3, NdF 3, TaF 3, NbOF 2, TaO 2F and TiO 2F is at least one of the fluorides; or an oxide containing at least one of Mg, Al, Ti, Si, Zn, Zr, Hf, Ta, Bi, Cr, Ga, La, Gd, Sr, and Ba; or a nitride containing at least one of Mg, Al, Ti, Si, Zn, Zr, Hf, Ta, Bi, Cr, Ga, La, Gd, Sr, and Ba. (10) The magnetoresistive element described in (9) above has a third magnetic layer 16 on the third non-magnetic layer 15. (11) The magnetoresistive element described in (10) above uses a magnetic thin film with a crystal structure having bcc (001) alignment in the first magnetic layer 11, the second magnetic layer 13, and the third magnetic layer 16. (12) The magnetoresistive element described in (10) above uses a magnetic thin film with an amorphous structure in the first magnetic layer 11, the second magnetic layer 13, and the third magnetic layer 16. (13) The magnetoresistive element described in any of (1) to (3), (9), (10) above uses a magnetic thin film with a crystal structure having bct(001) alignment in the first magnetic layer 11. (14) The magnetoresistive element described in (13) above uses Ir in the bottom layer 10. (15) A magnetic sensor having a magnetoresistive element as described in any one of (1) to (14) above. (16) A magnetic memory having a magnetoresistive element as described in any one of (1) to (14) above.

[0059] 10: Bottom layer 11: First magnetic layer 12: First non-magnetic layer 13: Second magnetic layer 14: Second non-magnetic layer 15: Third non-magnetic layer 16: Third magnetic layer 34: Cap layer 41: Wiring 1 42: Second wiring 51: Insulating material layer 60: Silicon semiconductor substrate 61: Gate electrode 62: Gate oxide film 63: Channel Formation Area 64A, 64B: Source / Drain Regions 65, 66: Connecting holes 67: First interlayer insulation layer 68: Second interlayer insulation layer 100: Magnetoresistive element TR: Selecting the transistor

Claims

1. A magnetoresistive element, characterized in that it comprises a first magnetic layer, a second magnetic layer, and a first non-magnetic layer disposed between the first magnetic layer and the second magnetic layer, wherein a second non-magnetic layer is disposed between the first non-magnetic layer and the second magnetic layer, and the first non-magnetic layer comprises a fluorine-containing insulating material, and the second non-magnetic layer has a non-magnetic layer comprising a stacked structure using a fluoride insulator, an oxide insulator, or a nitride insulator.

2. The magnetoresistive element of claim 1, wherein the first non-magnetic layer comprises an insulating material containing fluorine, oxygen or nitrogen.

3. The magnetoresistive element of claim 1, wherein a perpendicular magnetizing film is used in either the first magnetic layer or the second magnetic layer, or in either the first magnetic layer or the second magnetic layer.

4. The magnetoresistive element of claim 1, wherein the first nonmagnetic layer comprises at least one fluoride selected from LiF, NaF, AgF, CsF, KF, RbF, CuF2, CoF2, MgF2, MnF2, NiF2, PdF2, ZnF2, CaF2, SrF2, PbF2, BaF2, CdF2, EuF2, AlF3, BiF3, InF3, CrF3, FeF3, GaF3, RhF3, SbF3, AuF3, HfF4, SnF4, ZrF4, TiF4, NbF5, TaF5, WF6, CeOF, HoOF, LaOF, NdOF, PrOF, FeF3, MoF3, NdF3, TaF3, NbOF2, TaO2F, and TiO2F.

5. The magnetoresistive element as claimed in claim 1, wherein the first non-magnetic layer and the second non-magnetic layer comprise: LiF, NaF, AgF, CsF, KF, RbF, CuF2, CoF2, MgF2, MnF2, NiF2, PdF2, ZnF2, CaF2, SrF2, PbF2, BaF2, CdF2, EuF2, AlF3, BiF3, InF3, CrF3, FeF3, GaF3, RhF3, SbF3, AuF3, HfF4, SnF4, ZrF4, TiF4, NbF5, TaF5, WF6, CeOF, HoOF, La At least one fluoride selected from OF, NdOF, PrOF, FeF3, MoF3, NdF3, TaF3, NbOF2, TaO2F and TiO2F; or an oxide containing at least one of Mg, Al, Ti, Si, Zn, Zr, Hf, Ta, Bi, Cr, Ga, La, Gd, Sr and Ba; or a nitride containing at least one of Mg, Al, Ti, Si, Zn, Zr, Hf, Ta, Bi, Cr, Ga, La, Gd, Sr and Ba.

6. The magnetoresistive element of claim 1, wherein the first non-magnetic layer comprises LiF.

7. The magnetoresistive element of claim 1, wherein the laminated structure of the first non-magnetic layer and the second non-magnetic layer uses a laminated structure of fluoride and MgO.

8. The magnetoresistive element of claim 1, wherein a third non-magnetic layer is provided on the second magnetic layer, and the third non-magnetic layer comprises: LiF, NaF, AgF, CsF, KF, RbF, CuF2, CoF2, MgF2, MnF2, NiF2, PdF2, ZnF2, CaF2, SrF2, PbF2, BaF2, CdF2, EuF2, AlF3, BiF3, InF3, CrF3, FeF3, GaF3, RhF3, SbF3, AuF3, HfF4, SnF4, ZrF4, TiF4, NbF5, TaF5, WF6, CeOF, HoOF, La At least one fluoride selected from OF, NdOF, PrOF, FeF3, MoF3, NdF3, TaF3, NbOF2, TaO2F and TiO2F; or an oxide containing at least one of Mg, Al, Ti, Si, Zn, Zr, Hf, Ta, Bi, Cr, Ga, La, Gd, Sr and Ba; or a nitride containing at least one of Mg, Al, Ti, Si, Zn, Zr, Hf, Ta, Bi, Cr, Ga, La, Gd, Sr and Ba.

9. The magnetoresistive element of claim 8, wherein a third magnetic layer is provided on the aforementioned third non-magnetic layer.

10. The magnetoresistive element of claim 9, wherein a magnetic thin film having a crystal structure with bcc(001) alignment is used in the first magnetic layer, the second magnetic layer, and the third magnetic layer.

11. The magnetoresistive element of claim 9, wherein a magnetic thin film having an amorphous structure is used in the first magnetic layer, the second magnetic layer, and the third magnetic layer.

12. The magnetoresistive element of claim 1, wherein a magnetic thin film with a crystal structure having bct(001) alignment is used in the first magnetic layer.

13. The magnetoresistive element of claim 12 uses Ir in the aforementioned underlying layer.

14. A magnetic sensor having a magnetoresistive element as claimed in claim 1.

15. A magnetic memory having a magnetoresistive element as claimed in claim 1.

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