JP2008004654A - Magnetoresistive element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetoresistive element in which a ferromagnetic conductor thin film and a tunnel barrier thin film can be bonded with sufficient alignment, thereby preventing the characteristics from deteriorating due to poor bonding. <P>SOLUTION: In the magnetoresistive element 10, a tunnel barrier thin film 13 composed of Ga<SB>2</SB>O<SB>3</SB>is arranged between a (Ga, Mn)N thin film 11 where a part of Ga in GaN is replaced by Mn and a (Ga, Mn)<SB>2</SB>O<SB>3</SB>thin film 12 where part of Ga in Ga<SB>2</SB>O<SB>3</SB>is replaced by Mn. Both the (Ga, Mn)N thin film 11 and the (Ga, Mn)<SB>2</SB>O<SB>3</SB>thin film 12 are a p-type semiconductor exhibiting ferromagnetism. The (Ga, Mn)N thin film 11 can be bonded to the tunnel barrier thin film 13 with sufficient alignment by growing it epitaxially on the tunnel barrier thin film 13 as a substrate. The (Ga, Mn)<SB>2</SB>O<SB>3</SB>thin film 12 can be bonded to the tunnel barrier thin film 13 with sufficient alignment because it has basically the same crystal structure as that of the tunnel barrier thin film 13. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a magnetoresistive element used for recording information using magnetism, and more particularly to a tunneling magnetoresistive (TMR) element.

A TMR element is obtained by sandwiching a thin film having high electrical resistance between two ferromagnetic conductor thin films made of a material having both electrical conductivity and ferromagnetism of metal or semiconductor. In this element, when a voltage is applied between two ferromagnetic conductor thin films, and the magnetization directions of the two ferromagnetic conductor thin films are parallel, the tunnel passes through the high electrical resistance thin film. While current flows, almost no current flows when their magnetization directions are antiparallel. Thus, since the high electrical resistance thin film has a role as a tunnel barrier, this thin film is referred to as a tunnel barrier thin film in the present application.
The TMR element can be used as a memory element by utilizing the presence or absence of a tunnel current due to the difference in magnetization direction. In this memory element, information can be recorded by making the magnetization directions of the two ferromagnetic conductor thin films parallel / anti-parallel, and a voltage is applied between the two ferromagnetic conductor thin films. Information can be reproduced depending on whether or not the tunnel current is present.

Conventionally, TMR using a ferromagnetic metal thin film made of Fe, Co, Ni or their alloys as the ferromagnetic thin film and an oxide insulator such as Al ₂ O ₃ or MgO as the tunnel barrier thin film. Attempts have been made to fabricate devices. However, since these metals and oxide insulators have greatly different crystal structures, they cannot be joined with good consistency. Therefore, (i) current leaks through the tunnel barrier thin film due to the disorder of the crystal structure of the tunnel barrier thin film, (ii) electron tunneling is less likely to occur if the tunnel barrier thin film is thickened to prevent leakage, (iii) There is a possibility that the information cannot be correctly reproduced by the tunnel current because the electrons are scattered by the disorder of the structure of the ferromagnetic conductor thin film and the tunnel barrier thin film or at the interface between the two thin films.

  In a TMR element, the ferromagnetic conductor thin film is sufficient if it can conduct the current that has passed through the tunnel barrier thin film. Therefore, the material of the ferromagnetic conductor thin film (not limited to a good conductor) should be a semiconductor. You can also. As one type of such a ferromagnetic semiconductor, a diluted ferromagnetic semiconductor is known. A diluted ferromagnetic semiconductor is one in which only a part of atoms in a semiconductor crystal composed of non-magnetic atoms is substituted with a magnetic atom or a magnetic atom when ionized in the crystal. Although there is no clear standard for the number of atoms to be replaced, all of the conventionally known diluted magnetic semiconductors are those in which only 20% or less of the constituent atoms are replaced with atoms that are magnetic when ionized. is there. In this diluted ferromagnetic semiconductor, there are holes in an amount corresponding to the concentration of magnetic ions, and these holes are responsible for electrical conduction as a semiconductor. In addition, ferromagnetism is manifested by a magnetic interaction between the spins of each magnetic ion via a semiconductor carrier.

  Examples of such diluted ferromagnetic semiconductors include (Ga, Mn) As in which some Ga atoms in GaAs are substituted with Mn, and some In atoms in InAs are substituted in with Mn (In, Mn). As is known. Although these diluted magnetic semiconductors exhibit ferromagnetism at low temperatures, their ferromagnetic transition temperatures are about 110K for (Ga, Mn) As and about 30K for (In, Mn) As, both of which are ferromagnetic at room temperature. Not shown. Therefore, in order to use these materials for the ferromagnetic semiconductor of a device such as a TMR element, it is necessary to cool to a temperature lower than their ferromagnetic transition temperature, which is not practical.

  Patent Document 1 describes (Ga, Mn) N in which a part of Ga atoms of GaN is replaced with Mn as another example of a diluted ferromagnetic semiconductor. Since this material has a ferromagnetic transition temperature of about 940 K (about 670 ° C.), it can be used as a material for devices operating at room temperature.

JP2003-137698A

  However, even when (Ga, Mn) N is used for the ferromagnetic conductor thin film, the oxide insulator, which is the material of the tunnel barrier thin film, is used in the same manner as the case of using the metal ferromagnetic made of the above-mentioned good conductor Due to the difference in crystal structure, the two cannot be joined with good consistency, thereby causing a problem that information recorded in the element cannot be reproduced correctly.

  The problem to be solved by the present invention is that the ferromagnetic conductor thin film and the tunnel barrier thin film can be bonded with higher consistency than the conventional one, thereby preventing the deterioration of the characteristics due to the bonding failure. It is to provide a TMR element capable of performing

The first aspect of the magnetoresistive element according to the present invention to solve the above-mentioned problems is that each ferromagnetic semiconductor thin film includes a tunnel barrier thin film made of an insulator sandwiched between two ferromagnetic semiconductor thin films. In the magnetoresistive element formed by joining the tunnel barrier thin film,
Either one or both of the ferromagnetic semiconductor thin films have Ga ₂ O ₃ as a parent phase, and 0.5% to 15% of Ga in the parent phase is V, Cr, Mn, Fe, Co, Ni. It consists of a ferromagnetic p-type semiconductor substituted by any one or more kinds of atoms,
The tunnel barrier thin film is made of Ga ₂ O ₃ ;
It is characterized by

The magnetoresistive element according to the second aspect of the present invention is a magnetic element formed by sandwiching a tunnel barrier thin film made of an insulator between two ferromagnetic semiconductor thin films and bonding each ferromagnetic semiconductor thin film and the tunnel barrier thin film. In the resistance element,
Either one or both of the ferromagnetic semiconductor thin films have Ga ₂ O ₃ as a parent phase, and 0.5% to 15% of Ga in the parent phase is V, Cr, Mn, Fe, Co, Ni. It consists of a ferromagnetic p-type semiconductor substituted by any one or more kinds of atoms,
The tunnel barrier thin film has Ga ₂ O ₃ as a parent phase, and 0.5% to 15% of Ga in the parent phase is one or more of V, Cr, Mn, Fe, Co, and Ni Consisting of a paramagnetic insulator substituted with atoms of
It is characterized by that.

Hereinafter, 0.5% to 15% of Ga of the mother phase composed of Ga ₂ O ₃ is substituted with any one or plural kinds of atoms of V, Cr, Mn, Fe, Co, and Ni. A ferromagnetic p-type semiconductor is called a “Ga ₂ O ₃ -based diluted ferromagnetic p-type semiconductor”. In addition, 0.5% to 15% of Ga of the parent phase composed of Ga ₂ O ₃ is usually substituted with any one or more kinds of atoms of V, Cr, Mn, Fe, Co, and Ni. The magnetic insulator is referred to as “Ga ₂ O ₃ -based diluted paramagnetic insulator”. The two are collectively referred to as “Ga ₂ O ₃ -based dilute magnetic material”.

Ga ₂ O ₃ based dilute magnetic material, as mentioned above, part of Ga of the parent phase is replaced by atoms with magnetism such as V, and the substituted atoms are magnetized ions in the crystal Have a common configuration. In Ga ₂ O ₃ diluted magnetic materials, the difference in the average valence of magnetic ions occurs due to the number of missing O atoms, the number of proton impurities mixed between lattices, and the number of excess Ga atoms. Changes the magnetic and electrical conductivity. Specifically, when the average valence of magnetic ions approaches +2.0 or +3.0, magnetism becomes paramagnetic, and electrical conductivity becomes insulating (that is, Ga ₂ O ₃ based diluted paramagnetic insulator). On the other hand, when the average valence deviates from +2.0 and +3.0, the magnetism becomes ferromagnetic and the electrical conductivity exhibits the properties of a p-type semiconductor (ie, Ga ₂ O ₃ System diluted ferromagnetic p-type semiconductor). The number of O atoms and excess Ga atoms, such as by annealing in Ga ₂ O ₃ system in dilute magnetic oxide atmosphere or in a reducing atmosphere, the Ga ₂ O ₃ based dilute magnetic proton impurities in a gas containing water vapor Each can be changed by annealing or the like. The annealing conditions (heating temperature, gas concentration, etc.) vary depending on the type and concentration of magnetic ions, but can be determined by preliminary experiments.

Magnetization can be maximized when Mn is used as a substitution atom in a Ga ₂ O ₃ diluted ferromagnetic p-type semiconductor.

In the first embodiment, Ga ₂ O ₃ is an intrinsic semiconductor, but the band gap width is 4.9 eV, which is larger than the value in GaN known as a wide gap semiconductor (3.4 eV), so the electric resistance value is It is large enough to be used as a tunnel barrier thin film of a TMR element.

One of the ferromagnetic semiconductor thin films is a Ga ₂ O ₃ based diluted ferromagnetic p-type semiconductor, and the other is a ferromagnetic semiconductor in which 0.5% to 15% of GaN Ga is replaced with Mn (GaN based diluted semiconductor). Ferromagnetic p-type semiconductors can also be used. When Mn is used as a substitution atom in a Ga ₂ O ₃ diluted ferromagnetic p-type semiconductor, the former has a larger coercive force than the latter. Therefore, when a magnetic field smaller than the coercive force of Ga ₂ O ₃ -based diluted ferromagnetic p-type semiconductor and larger than the coercive force of GaN-based diluted ferromagnetic p-type semiconductor is applied to this TMR element, the former magnetization direction Can change only the direction of magnetization of the latter without changing (while being fixed). Thus, the magnetization directions of the two ferromagnetic conductor thin films can be easily made parallel or antiparallel to each other.
In this case, the Ga ₂ O ₃ diluted ferromagnetic p-type semiconductor thin film is called “pinned layer” because the magnetization direction does not change, and the GaN-based diluted ferromagnetic p-type semiconductor thin film changes in magnetization direction. It is called “free layer”.

In the magnetoresistive element according to the present invention, a Ga ₂ O ₃ -based diluted ferromagnetic p-type semiconductor is used for at least one of the _two ferromagnetic semiconductor thin films, and Ga ₂ O ₃ (first embodiment) is used for the tunnel barrier thin film. Or a Ga ₂ O ₃ -based diluted paramagnetic insulator (in the second embodiment). Therefore, the ferromagnetic semiconductor thin film and the tunnel barrier thin film have the same structure. Thereby, since both can be joined with good consistency, it is possible to prevent the deterioration of characteristics due to joining failure.

In the first aspect, the configuration in which the Ga ₂ O ₃ -based diluted ferromagnetic p-type semiconductor thin film and the Ga ₂ O ₃ insulator thin film are bonded is firstly used in a normal thin film manufacturing method such as a molecular beam epitaxial method. It can be easily manufactured by growing a thin film and growing the other thin film thereon.
Similarly, in the second embodiment, a structure in which a Ga ₂ O ₃ -based diluted ferromagnetic p-type semiconductor and a Ga ₂ O ₃ -based diluted paramagnetic insulator are joined is first grown on one thin film. The other thin film can be easily grown by changing the oxygen partial pressure. In the second aspect, after growing one thin film, only the vicinity of the surface of the thin film is exposed to an oxidizing atmosphere or a reducing atmosphere to produce a structure in which the two kinds of thin films are joined. it can.

A magnetoresistive element using a Ga ₂ O ₃ -based diluted ferromagnetic p-type semiconductor thin film for one of the ferromagnetic semiconductor thin films and a GaN-based diluted ferromagnetic p-type semiconductor thin film for the other has the following effects.
A thin film of a GaN-based diluted ferromagnetic p-type semiconductor can be produced by epitaxial growth on an insulating thin film made of a Ga ₂ O ₃ or Ga ₂ O ₃ -based diluted paramagnetic insulator. Since the GaN-based diluted ferromagnetic p-type semiconductor thin film thus fabricated and this insulating thin film are chemically bonded, the use of the insulating thin film as a tunnel barrier thin film reduces the characteristics due to the bonding failure. A magnetoresistive element that does not occur essentially can be obtained.
Also, since the coercivity of Ga ₂ O ₃ diluted ferromagnetic p-type semiconductor thin film is larger than that of GaN diluted diluted ferromagnetic p-type semiconductor thin film, the magnetic field is smaller than the former coercive force and larger than the latter coercive force. Can be easily switched between parallel and antiparallel spins between two diluted ferromagnetic p-type semiconductor thin films.

An embodiment of a magnetoresistive element according to the present invention is shown in FIG. This magnetoresistive element 10 includes a thin film 11 made of (Ga, Mn) N, which is a GaN-based diluted ferromagnetic p-type semiconductor in which part of Ga in GaN is replaced with Mn, and part of Ga in Ga ₂ O _3. A tunnel barrier thin film 13 made of Ga ₂ O ₃ is sandwiched between thin films 12 made of (Ga, Mn) ₂ O ₃ which is a Ga ₂ O ₃ diluted ferromagnetic p-type semiconductor substituted with Mn. In this embodiment, the concentration of Mn in the Ga site in the (Ga, Mn) N thin film 11 and the (Ga, Mn) ₂ O ₃ thin film 12 is 8%, and the (Ga, Mn) N thin film 11 and (Ga, M The thickness of the Mn) ₂ O ₃ thin film 12 is 300 nm. In addition, by producing the (Ga, Mn) ₂ O ₃ thin film 12 as described later, the average valence of Mn in this thin film becomes about +2.1, and this thin film has ferromagnetic and p-type semiconductor electrical characteristics. Have Here, the thickness of the tunnel barrier thin film 13 is 10 nm.

An example of a method for manufacturing the magnetoresistive element 10 will be described with reference to FIGS. First, a target 21A made of a raw material in which Ga ₂ O ₃ and MnO powders are mixed so that the ratio of the number of atoms of Ga and Mn is 93: 7, and a sapphire substrate 22 having a (0001) plane as its surface Is placed in a container 23 having an oxygen partial pressure of 0.05 Pa, and the target is irradiated with KrF pulsed laser light 24 having a frequency of 10 Hz while the sapphire substrate 22 is heated to 500 ° C. (FIG. 2). Is deposited on the sapphire substrate 22 (FIG. 3A). Thereby, the (Ga, Mn) ₂ O ₃ thin film 12 is produced on the sapphire substrate 22. Next, a target 21B made of Ga ₂ O ₃ is placed inside the container 23, and the same operation is performed while maintaining the oxygen partial pressure inside the container 23 at 0.2 Pa, thereby performing the (Ga, Mn) ₂ O ₃ thin film 12 A tunnel barrier thin film 13 made of Ga ₂ O ₃ is formed thereon (FIG. 3B). Then, the (Ga, Mn) N thin film 11 is formed on the tunnel barrier thin film 13 by using the molecular beam epitaxy method in the same manner as the conventional (Ga, Mn) N thin film manufacturing method (FIG. 3 (c)). . Thereby, the magnetoresistive element 10 is obtained (FIG. 3D).
Although the sapphire substrate 22 is not necessary as a component of the magnetoresistive element 10, it can be left as it is. When the sapphire substrate 22 is left, since sapphire is an insulator, the tunnel barrier thin film 13 is not formed on a part of the surface of the (Ga, Mn) ₂ O ₃ thin film 12 as shown in FIG. One of the electrodes 151 and 152 for detection may be provided in that portion.

The method for producing the (Ga, Mn) N thin film 11 shown in FIG. 3 (c) is a conventional application of a method for producing a GaN thin film using a Ga ₂ O ₃ thin film as a substrate. According to this method, the (Ga, Mn) N thin film 11 and the Ga ₂ O ₃ thin film (tunnel barrier thin film 13) can be joined with good consistency.

As described in Patent Document 1, the (Ga, Mn) N thin film 11 is known to exhibit ferromagnetic and p-type semiconductor electrical characteristics at room temperature. Here, to prepare only (Ga, Mn) ₂ O ₃ in order to confirm the characteristics of the thin film 12, using the aforementioned method shown in FIG. 3 (a) (Ga, Mn ) 2 O 3 thin film 12, Its electrical conductivity and magnetization were measured. As a result, electrical conductivity was confirmed to be conductive. As for the magnetization, the magnetization curve at room temperature has hysteresis as shown in FIG. 5, indicating that the (Ga, Mn) ₂ O ₃ thin film 12 is a ferromagnetic material.

The coercive force of the (Ga, Mn) ₂ O ₃ thin film 12 is about 100 Oersted (Oe), which is larger than the coercive force (50 to 60 Oersted) of the (Ga, Mn) N thin film 11. Therefore, by applying a magnetic field having a predetermined magnitude smaller than the coercive force of the (Ga, Mn) ₂ O ₃ thin film 12 and larger than the coercive force of the (Ga, Mn) N thin film 11 to the magnetoresistive element 10. Only the magnetization direction of the (Ga, Mn) N thin film 11 can be changed without affecting the magnetization of the (Ga, Mn) ₂ O ₃ thin film 12. Accordingly, a magnetic field larger than the coercive force is applied to the (Ga, Mn) ₂ O ₃ thin film 12 in advance to align the magnetization of the thin film in one direction, and in a direction parallel / antiparallel to the magnetization. Information of “1” or “0” can be stored by applying the magnetic field having the predetermined magnitude.

Next, an embodiment of a memory array using the magnetoresistive element according to the present invention will be described. FIG. 6 is a perspective view of the memory array 30 of the present embodiment. In this memory array 30, a large number of magnetoresistive elements 10 of the above embodiment are arranged in a matrix. One bit line 31 is arranged corresponding to each row of the matrix, and one recording word line 32 and one reproduction word line 33 are arranged corresponding to each column. The (Ga, Mn) ₂ O ₃ thin film 12 of each magnetoresistive element 10 is arranged directly below the bit line 31 corresponding to the row of the matrix to which the element belongs and is electrically connected to the bit line 31 ( The Ga, Mn) N thin film 11 is disposed immediately above the recording word line 32 corresponding to the column of the matrix to which the element belongs. One FET (field effect transistor) 34 having a channel made of a p-type semiconductor is provided for each magnetoresistive element 10, and the source electrode of the FET 34 is used as the (Ga, Mn) N of the magnetoresistive element 10. The drain electrode is connected to the thin film 11 and the gate electrode is connected to the reproducing word line 33 corresponding to the magnetoresistive element 10. Here, when the channel material of the FET 34 is p-GaN, the magnetoresistive element 10 and the FET 34 can be manufactured integrally.

The operation of the memory array 30 will be described with reference to FIGS. In advance, a magnetic field larger than the coercive force of the (Ga, Mn) N thin film 11 is applied to the memory array 30 in the direction of 45 ° with respect to the bit line and the recording word line 32 from the lower right to the upper left in FIG. As a result, the magnetization of the (Ga, Mn) N thin film 11 is aligned with the direction of the magnetic field.
When information is recorded in one magnetoresistive element 10A in the memory array 30, as shown in FIG. 8A, the bit line 31A passing immediately above the magnetoresistive element 10A has a right direction in FIG. In addition, a current having a magnitude described later is supplied to the recording word line 32A passing immediately below the magnetoresistive element 10A in the downward direction of FIG. As a result, a magnetic field in the upward direction in FIG. 7 is applied to the plurality of magnetoresistive elements 10 immediately below the bit line 31A, and the plurality of magnetoresistive elements 10 immediately above the recording word line 32A are applied to the plurality of magnetoresistive elements 10 in FIG. A magnetic field in the left direction is applied. In the other magnetoresistive elements 10, since the distance between the bit line 31A and the recording word line 32A is sufficiently large, these magnetic fields can be ignored. Of the magnetoresistive element 10 to which a magnetic field is applied, only the magnetoresistive element 10 </ _b > A has a magnetic field H ₁ larger than the magnetic field H ₂ applied to the other magnetoresistive elements 10 with respect to the bit line and the recording word line 32. Applied in the 45 ° direction. Accordingly, the magnetic field H ₁ is larger than the coercive force of the (Ga, Mn) N thin film 11 and smaller than the coercive force of the (Ga, Mn) ₂ O ₃ thin film 12, and the magnetic field H ₂ is reduced to the (Ga, Mn) N thin film. 11 and (Ga, Mn) ₂ O ₃ By setting the magnitude of the current flowing in the bit line 31A and the recording word line 32A so as to be smaller than the coercive force of the thin film 12, (Ga, Mn) ₂ O ₍₃₎ The magnetization direction of the (Ga, Mn) N thin film 11 can be changed from the lower right to the upper left in FIG. Thereby, the magnetization of the (Ga, Mn) N thin film 11 and the magnetization of the (Ga, Mn) ₂ O ₃ thin film 12 become parallel. Further, by passing a current of the same magnitude as described above through the bit line 31A and the recording word line 32A in the opposite direction, the magnetization of the (Ga, Mn) N thin film 11 and the (Ga, Mn) ₂ O ₃ The magnetization of the thin film 12 can be made antiparallel.

When reproducing the information recorded in the magnetoresistive element 10A, as shown in FIG. 8B, the reproducing word line 33A is connected between the reproducing word line 33A connected to the gate electrode of the magnetoresistive element 10A and the ground. A gate voltage that makes the line 33A side negative is applied, and a voltage that makes the bit line 31A side positive is applied between the bit line 31A and the ground. When the gate voltage is applied, the FET 34 can pass a current between the source electrode and the drain electrode. Therefore, the magnetization of the (Ga, Mn) N thin film 11 and the (Ga, Mn) ₂ O ₃ thin film If the magnetizations of 12 are parallel, current flows from the bit line 31A through the source electrode and drain electrode to the ground, whereas if these magnetizations are antiparallel, such current does not flow. By detecting the presence or absence of this current, information recorded in the magnetoresistive element 10A can be reproduced.

Here, the case where the FET 34 having a channel made of a p-type semiconductor is used has been described as an example. However, even when the FET having an n-type semiconductor channel is used (except for voltage and electrode polarity), A configuration similar to the example can be adopted. Further, the (Ga, Mn) N thin film 11 is disposed on the recording word line 32 side, and the (Ga, Mn) ₂ O ₃ thin film 12 is disposed on the bit line 31 side, and the (Ga, Mn) N thin film 11 and the bit line 31 are disposed. It is also possible to adopt a configuration in which these are electrically connected.

The longitudinal cross-sectional view which shows one Embodiment of the magnetoresistive element based on this invention. Longitudinal sectional view showing a manufacturing apparatus of Ga ₂ O ₃ system dilute ferromagnetic p-type semiconductor thin film used in the magnetoresistive element of this embodiment. The longitudinal cross-sectional view which shows the manufacturing method of the magnetoresistive element of this embodiment. The longitudinal cross-sectional view which shows the example which attaches an electrode to the magnetoresistive element of this embodiment. Graph showing the magnetization curves of used magnetoresistive element of this embodiment (Ga, Mn) ₂ O ₃ thin film (Mn concentration of 8%). The perspective view which shows one Embodiment of the memory array using the magnetoresistive element based on this invention. The top view for demonstrating storage of the information in the memory array of this embodiment. The perspective view for demonstrating storage (a) and reproduction | regeneration (b) of the information in the memory array of this embodiment.

Explanation of symbols

10, 10A ... magnetoresistive element 11 ... (Ga, Mn) N thin film _{12 ... (Ga, Mn) 2} O 3 thin film 13 ... tunnel barrier films 151, 152 ... electrode 21A, 21B ... raw materials of the target 22 ... sapphire substrate 23 ... Container 24 ... KrF pulse laser beam 30 ... Memory array 31, 31A ... Bit lines 32, 32A ... Recording word lines 33, 33A ... Reproduction word lines 33A ... Reproduction word lines 34 ... FET

Claims (5)

In a magnetoresistive element formed by sandwiching a tunnel barrier thin film made of an insulator between two ferromagnetic semiconductor thin films and joining each ferromagnetic semiconductor thin film and the tunnel barrier thin film,
Either one or both of the ferromagnetic semiconductor thin films have Ga ₂ O ₃ as a parent phase, and 0.5% to 15% of Ga in the parent phase is V, Cr, Mn, Fe, Co, Ni. It consists of a ferromagnetic p-type semiconductor substituted by any one or more kinds of atoms,
The tunnel barrier thin film is made of Ga ₂ O ₃ ;
The magnetoresistive element characterized by the above-mentioned. In a magnetoresistive element formed by sandwiching a tunnel barrier thin film made of an insulator between two ferromagnetic semiconductor thin films and joining each ferromagnetic semiconductor thin film and the tunnel barrier thin film,
Either one or both of the ferromagnetic semiconductor thin films have Ga ₂ O ₃ as a parent phase, and 0.5% to 15% of Ga in the parent phase is V, Cr, Mn, Fe, Co, Ni. It consists of a ferromagnetic p-type semiconductor substituted by any one or more kinds of atoms,
The tunnel barrier thin film has Ga ₂ O ₃ as a parent phase, and 0.5% to 15% of Ga in the parent phase is one or more of V, Cr, Mn, Fe, Co, and Ni Consisting of a paramagnetic insulator substituted with atoms of
The magnetoresistive element characterized by the above-mentioned.   3. The magnetoresistive element according to claim 2, wherein a part of O of the parent phase in the paramagnetic insulator is missing.   The magnetoresistive element according to claim 1, wherein the substitution atom in the ferromagnetic p-type semiconductor is Mn.   2. One of the ferromagnetic semiconductor thin films is the ferromagnetic p-type semiconductor, and the other is a ferromagnetic semiconductor in which 0.5% to 15% of Ga of GaN is replaced with Mn. The magnetoresistive element in any one of -4.

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