JP2957235B2 - Magnetic multilayer film - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a magnetic multilayer film suitable for a magnetoresistive element.

<Prior Art> An artificial lattice having a structure in which thin films having a thickness on the order of the atomic diameter of a metal are periodically stacked has attracted attention in recent years because it has characteristics different from those of a bulk metal. Have been.

As one type of such artificial lattice, there is a magnetic multilayer film in which a ferromagnetic metal thin film and an antiferromagnetic metal thin film are alternately laminated on a single crystal substrate.
Magnetic multilayer films such as a chromium type and an iron-manganese type (JP-A-60-189906) are known.

There is also a report that the iron-chromium type exhibits a magnetoresistance change of more than 40% at a very low temperature (4.2 K) (Physical Review Letters, vol. 61, p. 2472,
1988).

The main application of these magnetic multilayer films is a magnetoresistance effect element (MR element), and can be applied to various magnetic sensors (MR sensors), magnetic heads (MR heads), and the like.

The MR element detects the change in electric resistance of the magnetic film due to the application of a magnetic field and measures the magnetic field strength and its change. Generally, it is required that the magnetoresistance change rate at room temperature is large and the operating magnetic field strength is small. .

Conventionally, as a magnetic film of the MR element, a single-layer magnetic film of an Fe—Ni alloy or a Co—Ni alloy utilizing an anisotropic magnetoresistance effect has been used.

However, in a single-layer magnetic film of an Fe-Ni alloy or a Co-Ni alloy,
Although the operating magnetic field strength is small, the rate of change in magnetoresistance is as small as 2-3%.

In addition, although the above-described iron-chromium type magnetic multilayer film has a large magnetoresistance change rate, the operating magnetic field intensity is extremely large at about 20 kOe, so that practical application as an MR element is difficult.

<Problem to be Solved by the Invention> It is an object of the present invention to provide a magnetic multilayer film having a large magnetoresistance change rate and a small operating magnetic field strength.

<Means for Solving the Problems> Such an object is achieved by the present invention of the following (1) and (2).

(1) A magnetic multilayer film having a magnetoresistive effect, in which two or more magnetic thin films are laminated on a substrate via a non-magnetic thin film, and the direction of the axis of easy magnetization of at least one adjacent magnetic thin film A magnetic thin film having an easy axis of magnetization different from that of the magnetic thin film exists, and the thickness of the magnetic thin film and the thickness of the nonmagnetic thin film are each 20
A magnetic multilayer film having a thickness of 0 ° or less.

(2) The magnetic multilayer film according to the above (1), wherein the coercive forces of the two magnetic thin films having different directions of the axis of easy magnetization are different.

<Function> The magnetic multilayer film of the present invention has a configuration in which two or more magnetic thin films are laminated on a base via a non-magnetic thin film, and the direction of the axis of easy magnetization of at least one of the adjacent magnetic thin films is determined. There are magnetic thin films having easy axes of different orientations.

With such a configuration, an extremely large magnetoresistance change can be obtained.

The effect of the magneto-resistance effect in the magnetic multilayer film of the present invention will be described.

For the sake of simplicity, consider a laminate in which a magnetic thin film M ₁ , a non-magnetic thin film and a magnetic thin film M ₂ are stacked in this order.

Figure 1a is a schematic view showing the orientation of the magnetic thin film M ₁ and M ₂ each easy axis in a state where no external magnetic field exists. In FIG. 1a, the arrow marked in each magnetic thin film indicates the direction of spin in each magnetic thin film, and in the absence of an external magnetic field, the direction of spin matches the direction of the easy axis of magnetization.

Figure 1b and FIG. 1c shows a state in which an external magnetic field is applied to M ₁ and M _2, is larger strength of the external magnetic field H2 in FIG. 1c than the intensity of the external magnetic field H1 in Figure 1b .

The arrows in FIGS. 1b and 1c also indicate the spin directions.

In Figure 1b, the spin of each magnetic thin film is rotated by the influence of an external magnetic field, the angle between spin direction and M ₂ of the spin direction of the M ₁ is smaller than in Figure 1a.

Further, in FIG. 1c, the spin of each magnetic thin film is substantially parallel to the direction of the external magnetic field, the spin direction of the M ₁ and M ₂
Is almost parallel to the spin direction.

In the states shown in FIGS. 1a, 1b and 1c, the following changes occur in the electrical resistance of the laminate.

When an electric current is applied to the laminate in the state of Figure 1a, and spin M ₁
Since the spin of M ₂ is not parallel, conduction electrons are spin-scattered and exhibit high electric resistance.

In the state of Figure 1b, since the the spin direction and M ₂ spin and orientation of M ₁ is approaching parallel compared to the state of Figure 1a,
Spin scattering of conduction electrons is reduced, and electrical resistance is reduced.

Then, in the state of FIG. 1c, since where the spin direction and M ₂ spin and orientation of M ₁ substantially coincides with the conduction electrons is hardly spin scattering, electrical resistance becomes minimum.

By such an action, in a laminated body of two magnetic thin films having different directions of the axis of easy magnetization, a magnetoresistive effect in which electric resistance is changed by applying a magnetic field is exhibited.

In this case, the resistance of the laminate is maximum when the external magnetic field strength is zero, and decreases as the external magnetic field strength increases. The ratio of resistance decrease to external magnetic field strength increase is
Depending on the magnetic anisotropy energy and coercive force of the magnetic thin film, the smaller the magnetic anisotropic energy and coercive force, the easier the spin of the magnetic thin film is to rotate, so that the resistance decreases with a small magnetic field strength.

Therefore, the magnetic multilayer film of the present invention can set the operating magnetic field intensity to an extremely small range, and can cope with a minute change in the external magnetic field intensity. In addition, by appropriately selecting the magnetic anisotropic energy and the coercive force of the magnetic thin film, it is possible to obtain a magnetoresistive effect having various characteristics.

Magnetic thin film exists between M ₁ and M ₂ plays a role in regulating the exchange interaction acting directly on the M ₁ and M _2, is indispensable in the present invention.

If there is no non-magnetic thin film, the magnetic thin films will be in contact with each other, so that they will behave as if they were a single type of magnetic thin film due to exchange interaction, and even if no external magnetic field is applied, as shown in FIG. The spin directions of both magnetic thin films match, and the above-described magnetoresistance effect does not appear.

Even provided a non-magnetic thin film, usually because the remaining exchange interaction between M ₁ and M _2, the strength vary depending on the thickness of the nonmagnetic film, a magnetoresistive It can also be adjusted by the thickness of the non-magnetic thin film.

The above description is for a pair of magnetic thin films adjacent to each other with a non-magnetic thin film interposed therebetween, but when three or more magnetic thin films are stacked and the directions of the axes of easy magnetization of the adjacent magnetic thin films are different from each other. Since the above-described magnetoresistive effect occurs in all of these pairs of magnetic thin films, an effect of increasing the magnetoresistance change rate can be obtained.

Further, in the above description, only two types of magnetic thin films having different directions of easy magnetization axes are used. However, if three or more magnetic thin films having different directions of easy magnetization axes are used, more various resistance change characteristics can be obtained. Can be obtained.

In addition, since the anisotropic magnetoresistive effect generated in each magnetic thin film itself is added to the magnetoresistive effect by the above-described action, a higher magnetoresistance change rate can be obtained depending on the material constituting the magnetic thin film. is there.

In the magnetic multilayer film of the present invention, by selecting various conditions such as the direction of the axis of easy magnetization of each magnetic thin film, the magnetic anisotropy energy, the coercive force, the number of stacked magnetic thin films, and the thickness of the non-magnetic thin film, Since the magnetoresistance effect characteristics such as the resistance change rate and the operating magnetic field strength can be made various, the degree of freedom in design is extremely high.

In the present invention, for expressing the magnetoresistance effect if the orientation of the magnetic thin film M ₁ and M ₂ each easy axis different things, the composition and thickness of the two magnetic thin films may be the same.

The magnetic thin film and the non-magnetic thin film are extremely thin, not more than 200 mm, and are preferably formed by an ultra-high vacuum deposition method as described later. Thus, three or more types of vapor deposition are performed.

A ternary or more vapor deposition apparatus is extremely complicated and large-sized, and therefore expensive, and it is difficult to accurately detect the thickness of each thin film in a ternary or more vapor deposition apparatus.

In the present invention, the composition and thickness of both magnetic thin films can be the same, so that a magnetic multilayer film having the above-described magnetoresistance effect can be manufactured easily, accurately, and at low cost. Further, since the manufacturing conditions are stabilized, the yield is improved.

In the present invention, the compositions and / or thicknesses of the two adjacent magnetic thin films may be different from each other, and in this case, the degree of freedom in design is further increased.

<Specific Configuration> Hereinafter, a specific configuration of the present invention will be described in detail.

The magnetic multilayer film of the present invention is formed by laminating two or more magnetic thin films on a base via a non-magnetic thin film.

FIG. 2 is a sectional view of a magnetic multilayer film 1 according to a preferred embodiment of the present invention.

In FIG. 2, a magnetic multilayer film 1 has magnetic thin films M ₁ , M ₂ ,..., M _{n -1} and M _n on a base 2, and a non-magnetic thin film is provided between two adjacent magnetic thin films. It has thin films N ₁ , N ₂ ,..., N _n-2 , N _n-1 .

The material of the base 2 is not particularly limited, and may be appropriately selected from base materials used for ordinary artificial lattices such as magnesium oxide, glass, silicon single crystal, and gallium-arsenic single crystal.

The size of the base 2 is not particularly limited, and may be appropriately selected according to an element to be applied.

A base film may be formed on the surface of the base 2 on which the magnetic thin film is formed, if necessary.

As the base film, for example, an Au thin film having a thickness of about 200 mm is preferable, and when this Au thin film is heat-treated at about 150 ° C. for about 1 hour in a vacuum chamber, the surface becomes smooth in the atomic order, and the base film of the artificial lattice is formed. The effect becomes higher.

In the present invention, there is a magnetic thin film having an easy axis having a direction different from the direction of the easy axis of at least one adjacent magnetic thin film. That is, of the pairs of adjacent two magnetic thin films, there are pairs with different directions of the easy axis.

In the present invention, it is preferable that such a relationship is satisfied for all pairs of magnetic thin films adjacent to each other via the nonmagnetic thin film.

In order to stack magnetic thin films having different directions of easy magnetization axes, a magnetic thin film may be formed by a vapor deposition method in a magnetic field as described later.

In the present invention, the angle between the directions of the axes of easy magnetization of the adjacent magnetic thin films is preferably 20 degrees or more, particularly preferably 30 degrees or more. If this angle is less than 20 degrees, the rate of change in magnetoresistance decreases.

In this case, the direction of the axis of easy magnetization of the magnetic thin film is the spin direction of the magnetic thin film when no external magnetic field exists.

The upper limit of the angle between the directions of the axes of easy magnetization of the two magnetic thin films is 180 degrees. At this angle, the spins of the two magnetic thin films become antiparallel, and the resistance becomes maximum.

However, when the strength of the external magnetic field exceeds the coercive force of one magnetic thin film, the spin direction of only one magnetic thin film may be reversed depending on the direction of application of the external magnetic field. When the spin direction of one magnetic thin film is reversed, the angle formed by the spins of each magnetic thin film becomes a complement of the initial angle.

Therefore, in order to obtain a stable magnetoresistance effect, it is preferable to design in consideration of the relationship between the strength of the external magnetic field and the direction of application of the external magnetic field, the coercive force of each magnetic thin film, and the direction of the axis of easy magnetization.

The azimuth of the axis of easy magnetization of the magnetic thin film may be the in-plane direction or the thickness direction of the magnetic thin film.

In the present invention, the degree of the magnetic anisotropic energy of each magnetic thin film is not particularly limited. That is, if the anisotropic energy is low, the spin direction starts to change at a low magnetic field strength, and the spin change with respect to the magnetic field strength change becomes large, so that the operating magnetic field strength is low and a sharp magnetoresistance effect can be obtained.

Conversely, if the anisotropic energy is high, the operating magnetic field strength can be increased, and the operating range can be widened.

In addition, the magnetic anisotropy energy is, usually, 10~10 ⁸ erg / c
m ³ about and should be.

When there are a plurality of pairs of magnetic thin films having different easy-axis directions in the magnetic multilayer film, the angle or anisotropic energy of the easy-axis directions in each pair may be the same or different. Various designs are possible according to the desired rate of change in magnetoresistance and range of operating magnetic field strength.

The azimuth of the easy axis and the magnetic anisotropic energy can be measured by a torque meter. The measurement may be performed on a measurement sample in which a magnetic thin film is formed on a disk-shaped substrate under the same conditions as when forming a magnetic multilayer film. At this time, it is sufficient that the thickness of the magnetic thin film is 20 mm or more.

The magnetic thin films M ₁ , M ₂ ,..., M _n−1 , M _n are made of a magnetic material.

There is no particular limitation on the magnetic material used for the magnetic thin film, for example, a ferromagnetic material, an antiferromagnetic material, a ferrimagnetic material and a paramagnetic material, and specifically, Fe, Ni, Co, Mn, Cr, D
Preferred are y, Er, Nd, Tb, Tm, Ce and the like.

Also, alloys and compounds containing these elements can be preferably used. As alloys and compounds, for example, Fe
-Si, Fe-Ni, Fe-Co, Fe-Gd, Fe-Al-Si (such as Sendust), Fe-Y, Fe-Mn, Cr-Sb, Co-based amorphous alloy, Co-Pt, Fe-Al, Fe-C, Mn-Sb, Ni-Mn, Co-
O, Ni-O, Fe-O, Ni-F and the like are preferable.

In the present invention, one kind may be selected from these magnetic materials to form magnetic thin films having different easy magnetization axis directions.
Two or more magnetic materials may be used.

Further, the coercive forces of adjacent magnetic thin films may be different. In order to make the coercive force different, the composition and / or the thickness may be made different.

In this case, in addition to the magnetoresistance effect due to the difference in the orientation of the easy magnetization axis, a magnetoresistance effect due to the difference in coercive force appears.

When the coercive forces of adjacent magnetic thin films are different, a magnetoresistance effect is exhibited by the following action.

The coercive force of the magnetic thin film having a low coercive force is Hc1, and the coercive force of the magnetic thin film having a high coercive force is Hc2.

First, an external magnetic field is applied so that the magnetization directions of both magnetic thin films become parallel, and then the direction of the external magnetic field is reversed to increase its strength. Since the spin of the magnetic thin film of magnetic force is reversed first, the spin scattering of conduction electrons increases near Hc1 and Hc2, and the electrical resistance increases. Since such a magnetoresistance effect also utilizes the difference in spin between the two magnetic thin films, the presence of a non-magnetic thin film for adjusting the exchange interaction is essential.

In the present invention, the coercive force of the two magnetic thin films may be different in a pair of magnetic thin films having different directions of the easy magnetization axis. At least one pair of magnetic thin films may be provided in the magnetic multilayer film, and such pairs may have different coercive forces.

The thickness of the magnetic thin film is 200 ° or less, preferably 100 ° or less. Even if the thickness exceeds the above range, the effect of the present invention is not improved, and in order to form a good quality magnetic thin film with a uniform thickness, the film is formed at a relatively low speed by a method described later. Therefore, productivity is reduced.

There is no particular lower limit on the thickness of the magnetic thin film.
If it is Å or more, it is easy to keep the film thickness uniform,
The film quality is also good. Further, the amount of magnetization does not become too small.

The coercive force of each magnetic thin film may be appropriately set according to the purpose, for example, from the range of about 0.001 Oe to 10 kOe according to the external magnetic field strength or the required magnetoresistive effect characteristics of the element to which the element is applied. Absent.

Since the coercive force of the magnetic thin film existing in the magnetic multilayer film cannot be directly measured, it is usually measured as follows.

The total thickness of the magnetic thin film to be measured is 200 to 4
A sample for measurement is prepared by alternately depositing a non-magnetic thin film until the temperature becomes about 00 °, and the coercive force is measured. At this time, the thickness of the magnetic thin film, the thickness of the nonmagnetic thin film, and the composition of the nonmagnetic thin film are the same as those in the magnetic multilayer film. The direction of application of the magnetic field during measurement is the same as the direction of the magnetic field applied during the formation of the magnetic thin film.

The non-magnetic thin film is provided for relaxing or adjusting the interaction between the magnetic thin films existing on both sides.

 The non-magnetic thin film is composed of a non-magnetic material.

The non-magnetic material to be used is not particularly limited, and may be appropriately selected from various kinds of metal or metalloid non-magnetic material and non-metallic non-magnetic material.

Al, Mg, Mo, Zn, Nb, Ta,
V, Hf, Sb, Zr, Ga, Ti, Sn, Pb, Au, Ag, Cu, Pt and alloys thereof are preferable.
i, Ge, C, B and the like are preferable, and as the nonmetallic nonmagnetic material, a metal or semimetal compound such as SiO ₂ , SiO, SiN, Al ₂ O ₃ , ZnO, MgO, and TiN is preferable.

The electrical resistivity ρ of the nonmagnetic material used is 4.0 μΩ · c
m or more, and particularly preferably 12.0 μΩ · cm or more.
The electric resistivity in this case is a value in a bulk state and is measured at 20 ° C.

When a non-magnetic thin film is formed from a non-magnetic material having such an electrical resistivity, the ratio of electrons passing through the magnetic thin film increases, and as a result, the ratio of scattered electrons increases, resulting in a large rate of resistance change. can get.

The thickness of the non-magnetic thin film is 200 ° or less, preferably 80 ° or less, more preferably 60 ° or less. If the thickness exceeds the above range, the initial resistance of the entire magnetic multilayer film increases, and as a result, the rate of change in magnetoresistance decreases. Also,
As in the case of the above-described magnetic thin film, the productivity is reduced.

The thickness of the nonmagnetic thin film is preferably 4 mm or more, more preferably 8 mm or more, and still more preferably 12 mm or more.
Å or more. If the thickness is less than the above range, the exchange interaction between adjacent magnetic thin films becomes strong, and a sufficient magnetoresistance change rate cannot be obtained.

In the magnetic multilayer film, the thicknesses of the non-magnetic thin films need not all be the same. By making the thickness of the non-magnetic thin film two or more, further various designs are possible.

The thickness of a magnetic thin film or a non-magnetic thin film can be measured by a transmission electron microscope, a scanning electron microscope, an Auger electron spectroscopic analysis, and the crystal structure thereof is determined by X-ray diffraction or high-speed reflection electron diffraction. You can check.

In the magnetic multilayer film of the present invention, the number n of the magnetic thin films is not particularly limited, and may be appropriately selected according to a target magnetoresistance change rate. However, in order to obtain a sufficient magnetoresistance change rate, n Is preferably 3 or more, particularly preferably 6 or more. Further, although the resistance change rate increases as the number of layers increases, it is usually preferable to set n to 150 or less because productivity decreases as described above.

Note that an antioxidant film such as silicon nitride or silicon oxide may be provided on the surface of the uppermost magnetic thin film, or a metal conductive layer for leading electrodes may be provided.

In FIG. 2, the uppermost layer and the lowermost layer are magnetic thin films, but the uppermost layer and the lowermost layer may be nonmagnetic thin films.

The method for producing the magnetic multilayer film of the present invention is not particularly limited, and can be selected from various vapor deposition methods such as a vapor deposition method and a sputtering method. It is preferable to use a molecular beam epitaxy (MBE) method because a high quality film can be obtained.

The MBE method is a type of ultra-high vacuum deposition method in which molecules evaporated from an evaporation source are attached to the surface of a substrate in an ultra-high vacuum to grow a thin film.

Specifically, a vapor deposition source is selected by opening and closing a shutter,
Magnetic thin films and non-magnetic thin films are alternately deposited while measuring with a film thickness meter.

Then, in the present invention, a magnetic field is applied during the deposition of the magnetic thin film to impart magnetic anisotropy. There is no limitation on the magnetic field applying means, and ordinary means such as an electromagnet may be used.

Specifically, a magnetic thin film is formed while applying a magnetic field in parallel with the surface of the substrate held by the substrate holder, and the substrate holder is rotated by a predetermined angle each time the formation of each magnetic thin film is completed. To form In addition to the method of rotating the base in this manner, a method of installing two or more magnetic field applying means such as coils in the film forming apparatus and changing the magnetic field applying means used for each magnetic thin film formation may be used. .

As described above, in the present invention, a multilayer film having a magnetoresistance effect can be obtained only by changing the magnetic field application direction at the time of forming the magnetic thin film, so that it is not necessary to change the composition and thickness of the magnetic thin film at the time of vapor deposition. Therefore, a small-sized vapor deposition apparatus having a simple configuration can be used, and various controls during vapor deposition are extremely easy.

In the production of the magnetic multilayer film of the present invention, a normal MBE method may be used, and the film forming conditions are not particularly limited, but are usually 10 ^-11 to 10
The ultimate pressure is about ^-9 Torr, and the pressure during deposition is 10 ^-10 to 10 ^-8 T
It is preferable to form a film at a film forming rate of about 0.2 to 1.0 ° / sec at about orr.

In order to adjust the crystal structure of the thin film,
The substrate may be heated during film formation. The heating temperature is preferably set to 800 ° C. or lower to prevent diffusion between the thin films.

The magnetic multilayer film of the present invention is preferably applied to various MR elements such as an MR sensor and an MR head.

Normally, a bias magnetic field need not be applied when used, but may be applied as needed.

<Example> Hereinafter, the present invention will be described in more detail with reference to specific examples.

[Example 1] Magnetic thin films and non-magnetic thin films were alternately vapor-deposited on a magnesia single crystal substrate to prepare a magnetic multilayer film sample.

Table 1 below shows the configuration of a multilayer film composed of a magnetic thin film and a non-magnetic thin film.

In Table 1, for example, when [Fe (30) -Zn (20) -Co (30) -Zn (20)] ₁₀ is displayed, a 30-mm thick Fe thin film, a 20-mm thick Zn thin film, and a 30-mm thick This means that the step of sequentially depositing a Co thin film and a 20 ° Zn thin film was repeated 10 times. The thickness of each thin film was measured with a transmission electron microscope.

The vapor deposition was performed by the MBE method in a vacuum chamber at an ultimate pressure of 10 ^-9 to 10 ^-10 Torr.

The deposition rate was about 0.5 ° / sec, and the deposition was performed while rotating the substrate at 30 rpm.

 The substrate temperature during vapor deposition was 200 ° C.

When depositing the magnetic thin film, a magnetic field of 100 to 900 Oe was applied in the in-plane direction of the substrate to impart magnetic anisotropy to the magnetic thin film. The magnetic field application direction was set to two directions, the magnetic field was applied in the same direction when forming the odd-numbered magnetic thin films from the substrate side, and the magnetic field application direction was also unified when forming the even-numbered magnetic thin films. The applied magnetic field strength was the same in both directions.

Table 1 shows the angle formed between the direction of the easy axis of the odd-numbered magnetic thin film and the direction of the easy axis of the even-numbered magnetic thin film.

Table 1 shows the magnetic anisotropy energies of these magnetic thin films.

It was confirmed by a torque meter that the direction of the axis of easy magnetization of each magnetic thin film coincided with the direction of application of the magnetic field.
The magnetic anisotropy energy was also measured with a torque meter. These measurements were performed on a measurement sample in which a magnetic thin film was formed to a thickness of 200 mm on a disk-shaped substrate.

Table 1 shows the coercive force of the magnetic thin film used for each sample. Since the coercive force of the magnetic thin film in each sample cannot be measured directly, it was measured as follows.

The magnetic thin film to be measured and the non-magnetic thin film used for the sample were alternately vapor-deposited until the total thickness of the magnetic thin film became 400 mm to prepare a measurement sample, and the coercive force was measured. The thicknesses of the magnetic thin film and the non-magnetic thin film were the same as the thickness in the sample.

The coercive force was measured using a BH loop tracer and a vibrating magnetometer. The direction of application of the magnetic field during the measurement was the direction of the axis of easy magnetization.

Further, the sample shown in Table 1 was formed into a strip having a size of 0.3 mm × 1.0 mm, and the resistance when the external magnetic field was changed from −7 to +7 Oe at the maximum was measured by a four-terminal method.
R / R was determined.

The rate of change of resistance ΔR / R is defined as the maximum resistance value is Rmax, the minimum resistance value is Rmin, Calculated as

 Table 1 shows the results.

The direction in which the external magnetic field was applied during the resistance measurement was a direction intermediate between the direction of the easy axis of the odd-numbered magnetic thin film and the direction of the easy axis of the even-numbered magnetic thin film.

From the results shown in Table 1, the effect of the present invention is clear.

That is, in the magnetic multilayer film of the present invention, the magnetoresistance effect can be exhibited by changing the direction of the axis of easy magnetization of the adjacent magnetic thin films, and the magnetic thin film can be operated with an extremely small magnetic field strength.

In addition, as a substrate, glass, gallium-arsenic single crystal,
Even when silicon, strontium titanate, calcium titanate or ferrite was used, the same effects as those of the above samples were observed.

<Effect of the Invention> The magnetic multilayer film of the present invention is suitable for an MR element because it has a large magnetoresistance change rate and can set a small operating magnetic field strength.

In addition, the operating magnetic field strength can be set relatively freely.
Since it has a high degree of freedom in design, it can be applied to various uses such as MR sensors and MR heads.

[Brief description of the drawings]

FIG. 1a, FIG. 1b and FIG. 1c are schematic diagrams for explaining the operation of the present invention. FIG. 2 is a partially omitted cross-sectional view of the magnetic multilayer film of the present invention. REFERENCE NUMERALS 1 ...... magnetic multilayer film 2 ...... base _{M 1, M 2, ...,} M n-1, M n ...... magnetic thin film _{N 1, N 2, ...,} N n-2, N n-1 ... … Non-magnetic thin film

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-1-91482 (JP, A) JP-A-1-300504 (JP, A) JP-A-2-116181 (JP, A) JP-A-2- 249210 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) H01F 10/08 H01L 43/08

Claims (2)

(57) [Claims] 1. A magnetic multilayer film having a magnetoresistive effect, wherein two or more magnetic thin films are laminated on a substrate via a non-magnetic thin film, and an easy axis of magnetization of at least one of the adjacent magnetic thin films is provided. There is a magnetic thin film having an easy axis of magnetization different from that of the magnetic thin film, and the thickness of the magnetic thin film and the thickness of the non-magnetic thin film are 200
磁性 The following magnetic multilayer film. 2. The magnetic multilayer film according to claim 1, wherein the coercive forces of the two magnetic thin films having different directions of the axis of easy magnetization are different.