JP2010109021A - Multiferroic electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multiferroic electronic apparatus capable of inducing a current in an alternate current magnetic field, or controlling the strength and the direction of electric polarization. <P>SOLUTION: A multiferroic nano electric generator has a structure composed of a multiferroic solid material 1 sandwiched by metal electrodes 2. The structure is constituted so as to apply an alternate current magnetic field 5 in parallel with the metal electrodes 2, and a current induced between the metal electrodes 2 is utilized. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a multiferroic element as a new functional element having both ferroelectricity and ferromagnetism, and it is possible to generate a displacement current by repetitive magnetization reversal. provide. Further, an element capable of generating electric polarization by an external magnetic field and controlling the intensity and direction thereof is provided. Further, it is used for a magnetic sensor necessary for reading information stored by magnetization. Further, this element can be applied to a technology related to a memory element.

The present inventors are a multiferroic solid material having both ferroelectricity and ferromagnetism, MCr ₂ O ₄ (M = Mn, Fe, Co, Ni) compound (see Patent Document 1 below), or Y A multiferroic element using generation of electric polarization by an external magnetic field in a type ferrite compound has been proposed (see Non-Patent Document 1).
International Publication No. 07/135817 S. Ishiwata et al. , Science, Vol. 319, no. 5870, pp. 1643 (2008) Z. Somogyvari et al. , Journal of Magnetics and Magnetic Materials, Vol. 304, pp. e775-e777 (2006) H. Katsura et al. Phys. Rev. Lett. Vol. 95,057205 (2005) L. Kalvoda et al. , Journal of Magnetics and Magnetic Materials, Vol. 87, pp. 243-249 (1990)

MCr ₂ O ₄ already proposed as described above (M = Mn, Fe, Co , Ni) Y -type ferrite material, such as a compound or a Ba ₂ Mg ₂ Fe ₁₂ O _22, there are problems such as saturation magnetic polarization is small, It has not been put into practical use as a permanent magnet. Therefore, if the multiferroic function is obtained with the same or the same kind of raw material as the permanent magnet solid material that has already been put into practical use as a permanent magnet, the main starting materials are the same, and the firing conditions of the subsequent production process are also the same. It is very desirable from the viewpoint of productivity because it can be made the same condition.

In view of the above situation, the present invention is an M (magnetoprambite) type ferrite compound that has already been produced in large quantities in the market, can induce current with an external magnetic field, and can control the strength and direction of electric polarization. An object is to provide an electronic device. In particular, M (Magnet Plumbite) type ferrite expressed as AFe ₁₂ O ₁₉ or AO 6 (Fe ₂ O ₃ ), characterized in that A is an element composed of Ba and Sr, is widely used in the world today. It is the magnet that has the largest production volume among the permanent magnets that are used. In fact, the production of permanent magnets in 2004 is 690,000 tons per year, including both M-type sintered ferrite magnets and M-type ferrite bonded magnets. Therefore, even after the development of rare earth magnets with a strong magnetic susceptibility, the number has been increasing year by year.

  It is an object of the present invention to provide a multiferroic electronic device related to this M-type ferrite permanent magnet.

In order to achieve the above object, the present invention provides
[1] In a multiferroic electronic device, it is made of a multiferroic solid material having both ferroelectricity and ferromagnetism made of M (magnetoprambite) type ferrite, and an external magnetic field is applied to the multiferroic solid material. It is characterized by inducing a current.

  [2] In a multiferroic electronic device, it is made of a multiferroic solid material having both ferroelectricity and ferromagnetism made of M (magnetoprambite) type ferrite, and an external magnetic field is applied to the multiferroic solid material. Thus, the intensity and direction of electric polarization can be controlled.

[3] The multiferroic electronic device described in [1] or [2], wherein multiferroic solid state material is a M-type ferrite AFe ₁₂ O _19, A is Ca, Ba, Sr, Pb or their It is an element which consists of a mixture of these two types of elements.

[4] The multiferroic electronic device described in [1] or [2], wherein multiferroic solid state material is a M-type ferrite _{AFe 12-x B x O 19} , A is Ca, Ba, Sr , Pb or a mixture of these two elements, B is a trivalent element made of rare earth such as Sc, Y, Ac, Ce, Pr, etc., and the range of x is 0 <x ≦ 2. And

[5] In the multiferroic electronic device according to [1] or [2], the multiferroic solid material is an AFe _12-2x B _x C _x O ₁₉ M-type ferrite, and A is Ca, Ba , Sr, Pb or a mixture of these two elements, B is a tetravalent element such as Ti and Zr, C is a divalent element composed of Mg, Zn, Co, Ni and Cu, and x The range is characterized in that 0 <x ≦ 3.

[6] In the multiferroic electronic device according to [1] or [2], the multiferroic solid material is M-type ferrite of AFe _12-xy B _x C _y O ₁₉ , wherein A is Ca, Ba , Sr, Pb or a mixture of these two elements, B is a trivalent element made of a rare earth such as Sc, Y, Ac, Ce, Pr, etc. C is made of Mg, Zn, Co, Ni, Cu. The range of x is 0 <x ≦ 2, and the range of y is 0 <y ≦ 1.

[7] In the multiferroic electronic device according to the above [1] or [2], the multiferroic solid material is AFe _12-2x-y B _x C _x D _y O ₁₉ M-type ferrite, Is composed of Ca, Ba, Sr, Pb or a mixture of these two elements, B is a tetravalent element such as Ti, Zr, etc. C is a divalent element composed of Mg, Zn, Co, Ni, Cu. D is also a divalent element composed of Mg, Zn, Co, Ni and Cu, and the range of x is 0 <x ≦ 3, and the range of y is 0 <y ≦ 1.

  [8] In the multiferroic electronic device according to the above [1] or [2], the multiferroic solid material is grown in a high-temperature gas atmosphere having an oxygen gas atmosphere of 2 atm or higher by a light lamp in a high temperature gas zone. A single crystal is grown by the method.

  [9] In the multiferroic electronic device according to the above [1] or [2], the multiferroic solid material is additionally subjected to heat treatment in a range of 400 ° C. to 1000 ° C. in a range of 100 to 400 hours in oxygen. The helical magnetic transition temperature is increased to 400K.

  According to the present invention, the following effects can be achieved.

  (1) Since a displacement current continues to flow through the wiring due to repetitive alternating magnetic field (magnetic field reversal), it functions as a nano-sized generator incorporating a nanometer-sized power generation coil. For example, by applying a repetitive magnetic field from outside the human body, driving power can be applied to a micro motor in a blood vessel of the human body.

  (2) Since the magnetic sensor part and the electric polarization generating part can be made of the same solid material, it can be used as a data reading magnetic sensor that functions without having a special shape. As a result, the structure of the magnetic sensor element is simplified, resulting in significant cost merit. Since this magnetic sensor element can be miniaturized to the nano size, it becomes a magnetic sensor that can cope with the miniaturization of the magnetization region for storing information. Since this magnetic sensor can control the electric polarization with an external magnetic field, it becomes a highly sensitive magnetic sensor.

  (3) Since the multiferroic memory element (MFM element) is electric field induced unlike the current induced magnetic field, the current consumption can be greatly suppressed. Furthermore, since the induced magnetization has hysteresis, it has a memory effect and becomes a nonvolatile memory element. Since the element structure is also simple, a minute memory can be formed, and a high-density memory becomes possible. Fewer layer configurations dramatically reduce process costs. A new multiferroic nonvolatile memory element (MFM element) with low power consumption, high integration, and low manufacturing cost can be provided.

  The multiferroic electronic device of the present invention is made of a multiferroic solid material having both ferroelectricity and ferromagnetism made of M (magnetoprambite) type ferrite, and an external magnetic field is applied to the multiferroic solid material. To induce a current.

  The multiferroic nanogenerator has a structure made of a multiferroic solid material sandwiched between metal electrodes, and is arranged to apply an alternating magnetic field in parallel to this electrode, and uses the current flowing between the electrodes. To do.

  A multiferroic magnetic sensor element has a structure made of a multiferroic solid material sandwiched between metal electrodes, and is generated in a direction substantially perpendicular to the magnetic field generated by a leakage magnetic field of magnetization corresponding to information. What is necessary is just to set it as the structure which detects an electric polarization with a voltmeter.

  The multiferroic memory device is made of a multiferroic solid material sandwiched between two metal electrodes, and is selected by applying a voltage between a specific selected bit line and a word line. Magnetization is generated in a specific direction in the multiferroic memory element sandwiched between the bit line and the word line. The generated magnetization has a memory function. A non-magnetic solid material is embedded between the memory elements. Data can be read by determining 0 or 1 based on the voltage intensity caused by the electric polarization generated between a specific selected bit line and word line.

  Hereinafter, embodiments of the present invention will be described in detail.

  FIG. 1 is a schematic diagram showing a basic configuration of a multiferroic nanogenerator as an electronic device according to the present invention.

  In this figure, 1 is a multiferroic solid material, 2 is a metal electrode formed on both sides of the multiferroic solid material 1, 3 is a wiring connected to the metal electrode 2, and 4 is an electrical connection connected to the wiring 3. The device 5 is an alternating magnetic field that acts on the multiferroic solid material 1.

  As shown in FIG. 1, the multiferroic nanogenerator has a structure made of a multiferroic solid material 1 sandwiched between metal electrodes 2 and is arranged so as to apply an alternating magnetic field 5 in parallel to the metal electrodes 2. Then, the current flowing between the metal electrodes 2 may be used for the operation of the electric device 4. In this multiferroic nano-generator, the displacement current 6 continues to flow through the wiring 3 due to repetitive alternating magnetic field (magnetic field reversal) 5, so that the multi-ferroic nano-generator functions as a nano-sized generator incorporating a nanometer-sized power generation coil. . For example, by applying a repetitive magnetic field from outside the human body, driving power can be applied to a micro motor in a blood vessel of the human body.

  FIG. 2 is a schematic diagram showing a basic configuration of a multiferroic magnetic sensor as an electronic device according to the present invention.

  In this figure, 11 is a multiferroic solid material, 12 is a metal electrode formed on both sides of the multiferroic solid material 11, 13 is a wiring connected to the metal electrode 12, and 14 is a voltage connected to the wiring 13. A total of 15 is a perpendicular magnetic recording material in which data acting on the multiferroic solid material 11 is stored.

  As shown in FIG. 2, the multiferroic magnetic sensor element has a structure made of a multiferroic solid material 11 sandwiched between metal electrodes 12, and has a leakage magnetic field of magnetization corresponding to information of the perpendicular magnetic recording material 15. What is necessary is just to make it the structure which measures the electric polarization which generate | occur | produced in the direction substantially perpendicular | vertical to the magnetic field with the voltmeter 14 with the generated magnetic field.

  Since this multiferroic magnetic sensor element can generate electric polarization by a magnetic field from the perpendicular magnetic recording material 15 in which data is stored, it functions as a magnetic sensor for reading data.

  In this case, since the magnetic sensor unit and the electric polarization generating unit can be made of the same solid material, they function without having a special shape. As a result, the structure of the magnetic sensor element is simplified, resulting in significant cost merit. In addition, since this magnetic sensor element can be miniaturized to a nano size, it can be a magnetic sensor that can cope with the miniaturization of the magnetization region for storing information.

  FIG. 3 is a schematic diagram showing a basic configuration of a multiferroic memory as an electronic apparatus according to the present invention.

  In this figure, 21 is a multiferroic solid material, 22 is upper and lower metal electrodes, 23 is a multiferroic memory cell, 24 is a bit line, and 25 is a word line.

  As shown in FIG. 3, the multiferroic memory element includes multiferroic memory cells 23 arranged in a plane and made of a multiferroic solid material sandwiched between two metal electrodes 22. A voltage is applied between a specific selected bit line 24 and a word line 25 from a direct current power supply or an alternating current power supply via a wiring, so that a multi-feature sandwiched between the selected bit line 24 and the word line 25 is applied. Magnetization in a specific direction is generated in the Loic memory cell 23. The generated magnetization has a memory function. A multiferroic solid material is embedded between the memory elements. On the other hand, in reading data, 0 or 1 is determined based on the voltage intensity caused by the electric polarization generated between a specific selected bit line 24 and word line 25.

  FIG. 4 is an experimental layout showing a confirmation experiment of magnetic field induced current generation of the multiferroic element according to the present invention, and FIG. 5 is a diagram showing the correlation between the crystal orientation and the external magnetic field.

  In these figures, 31 is a multiferroic solid material, 32 is a metal electrode formed vertically so as to sandwich the multiferroic solid material 31, 33 is a magnetic field applied from the outside, and 34 is the direction of the generated electric polarization. It is. Reference numeral 35 denotes an ammeter for measuring a current between the upper and lower metal electrodes 32 of the multiferroic solid material 31 generated by the induced electric polarization. A silver paste is used as the electrode material, but there is no problem even if other metals such as aluminum and gold are used.

FIG. 5 shows the correlation between the crystal orientation, the external magnetic field, and the electrode arrangement when BaFe _10.4 Sc _1.6 O ₁₉ is used among the compounds having the M-type ferrite structure as the multiferroic solid material 31. As is clear from this figure, the direction of the external magnetic field is 45 ° from the crystal axis [100] of the hexagonal structure of BaFe _10.4 Sc _1.6 O ₁₉ , and the generated electric polarization is the [120] direction.

FIG. 6 is a diagram showing the external magnetic field dependence of the electric polarization when an external magnetic field is applied to the BaFe _10.4-δ Sc _1.6 Mg _δ O ₁₉ (δ = 0.05) crystal material which is the _multiferroic solid material of the present invention. FIG. 7 is a diagram showing the relationship between the crystal orientation of the hexagonal structure of the multiferroic solid material used in FIG. 6, the external magnetic field, and the generated charges.

  As shown in these figures, a magnetic field of 10K Oersted is applied in advance at an angle of 45 degrees from the [100] direction to the [001] direction, and an electric field of about several hundred V / cm is applied in the [120] direction (polling). ). Thereafter, when an external magnetic field is applied from zero to plus at an angle of 45 degrees from the [100] direction to the [001] direction, [120] direction electric polarization (solid line) is generated in the plus direction. When the external magnetic field is changed from zero to minus, the electric polarization changes to minus. When the poling conditions are the same magnetic field direction as described above and a negative electric field is applied in the [120] direction, the generated electric polarization is reversed (broken line). The measurement temperature is -263 ° C.

FIG. 8 is a characteristic diagram when the current or electric polarization is applied to the multiferroic solid material of the present invention. FIG. 8A shows the displacement current (pA / mm ² ) with respect to the elapsed time (sec). (B) shows the electric polarization (μC / m ² ) with respect to the elapsed time (sec), and FIG. 8 (c) shows the alternating magnetic field (kOe) with respect to the elapsed time (sec).

BaFe _10.4-δ Sc _1.6 Mg _δ O ₁₉ (δ = 0.05) When an alternating magnetic field oscillating positively and negatively is applied to the crystal material (FIG. 8C), positive and negative displacement currents flow in accordance with the alternating magnetic field. It can be seen that [FIG. 8 (a)] and electrical polarization alternately occur in positive and negative [FIG. 8 (b)]. This result shows that an alternating current and a potential are generated by alternating magnetization.

FIG. 9 shows the crystal structure and magnetic structure of BaFe ₁₂ O ₁₉ , which has the same crystal structure as the BaFe _10.4-δ Sc _1.6 Mg _δ O ₁₉ (δ = 0.05) crystal (the direction of spin is indicated by an arrow). The crystal structure is a hexagonal crystal structure. As shown in the figure, the hcp structure R block of the ABAB ... sequence and the ABCABC fcc structure S block share a c axis to form one molecule, and R ^* S ^* rotated 180 degrees about this axis ^. Two molecules together with the block form one unit cell. Six upward spins across S and R (a), two downward spins in the R block (b), one upward spin in the S block (c), two downward spins in the S block ( d), in an upward spin one R block (e), the magnetic moment per molecule becomes _{(8-4) * 5μ B = 20μ} B. The magnetic structure is a ferri-type spin structure having an easy axis of magnetization in the [001] direction. A major factor that these M-type ferrites are excellent permanent magnet materials is the presence of large uniaxial crystal anisotropy energy having the c-axis direction as the easy magnetization direction. It is ferrimagnetic (a type of ferromagnetism) at room temperature.

Note that the magnetic structure of the BaFe _10.4-δ Sc _1.6 Mg _δ O ₁₉ (δ = 0.05) crystal is different from that of BaFe ₁₂ O _{19 at} a low temperature and has a conical spiral spin structure (see FIG. 10). .

FIG. 11 is a diagram showing the temperature dependence of the magnetization of the BaFe _10.4 Sc _1.6 O ₁₉ crystal material, which is a multiferroic solid material according to the present invention.

  As shown in this figure, the magnetization M // [001] in the c-axis direction decreases from around 250 K (−23 ° C.). This is because the c-axis component decreases because the spin in the c-axis direction deviates from the [001] direction to form a conical spiral spin structure. This is confirmed by Mossbauer's experiment [Non-patent Document 2]. In the case of such a conical spiral spin structure, when an external magnetic field is applied in a direction deviated from the [001] direction into the paper surface, it is predicted that electric polarization is generated perpendicular to the paper surface. Reference 3]. Here, the reason why 0.05 is doped with Mg is to prevent a reduction in electrical resistance due to the fact that divalent iron is mixed during the preparation of a small amount of sample.

As described above, in the case of BaFe _10.4-δ Sc _1.6 Mg _δ O ₁₉ (δ = 0.05) having the M-type ferrite structure of _multiferroic material, the current and electric polarization are generated by an external magnetic field, and the strength of the electric polarization is controlled. It was demonstrated for the first time that it was possible. The applied magnetic field strength is about 4000 Gauss in this example. Furthermore, if a material is selected, it can be induced by a weak magnetic field, and the current density can be further improved.

  Such magnetic field induced current generation and charge generation occur at −23 ° C. or lower, but since this phenomenon occurs in a spin state exhibiting conical spiral spin magnetism, if the conical spiral spin magnetic transition is brought to a high temperature, Good. By adding a heat treatment in the range of 400 ° C. to 1000 ° C. in the range of 100 to 400 hours in oxygen, it is possible to further increase the helical magnetic transition temperature. Furthermore, the possibility of normal temperature is high by optimizing the temperature process.

Also, in BaFe _10.8 Ti _0.6 Mg _0.6 O ₁₉ and BaFe ₈ Ti ₂ Co ₂ O ₁₉ , the same effect occurs because the spin structure has a conical spiral spin structure [Non-patent Document 4]. Is clear.

FIG. 12 is a photograph in place of a drawing showing a single crystal of BaFe _10.4 Sc _1.6 O ₁₉ which is a multiferroic solid material according to the present invention.

BaFe _10.4 Sc _1.6 O ₁₉ is a single crystal produced by a floating melting zone manufacturing method using a light source such as a halogen lamp in a high-pressure gas atmosphere. When the gas species to be applied is oxygen gas, a single-phase hexagonal crystal structure can be obtained if the pressure is 2 atm or higher.

Thus, it is shown that _multiferroic solid material BaFe _10.4-δ Sc _1.6 Mg _δ O ₁₉ (δ = 0.05) having both ferromagnetism and ferroelectricity can control current and electric polarization by an external magnetic field. This shows that it is possible to generate electric polarization and generate magnetization by an electric field which is the reverse process. In a ferroelectric, the positive and negative directions of electric polarization can be controlled by an electric field. It is obvious that if the electric polarization is reversed at this time, the magnetization is reversed at the same time in the multiferroic material having the spin spiral structure.

  In addition, this invention is not limited to the said Example, Based on the meaning of this invention, a various deformation | transformation is possible and these are not excluded from the scope of the present invention.

  The multiferroic element of the present invention can be used for a nano-sized power generation device, a magnetic sensor that reads information on an element stored by magnetization, or a low-cost memory element.

It is a schematic diagram which shows the basic composition of the multiferroic nanogenerator as an electronic device concerning this invention. It is a schematic diagram which shows the basic composition of the multiferroic magnetic sensor as an electronic apparatus concerning this invention. It is a schematic diagram which shows the basic composition of the multiferroic memory as an electronic device concerning this invention. It is an experiment arrangement | positioning figure which shows the confirmation experiment of the magnetic field induction electric current generation of the multiferroic element concerning this invention. Among the compounds having the M-type ferrite structure as a multiferroic solid state material in FIG. 4 is a diagram showing the correlation between the crystal orientation and the external magnetic field in the case of using the BaFe _10.4 Sc _1.6 O _19. Is a diagram illustrating an external magnetic field dependence of the electrical polarization in the case of applying an external magnetic field to the multiferroic _{BaFe 10.4- δ Sc 1.6 Mg δ O} 19 (δ = 0.05) is a solid state material crystal material of the present invention. It is a figure which shows the relationship between the crystal orientation of the hexagonal structure of the multiferroic solid material used in FIG. 6, an external magnetic field, and the electric charge which generate | occur | produces. In BaFe _10.4 Sc _1.6 O ₁₉ a multiferroic solid state material of the present invention, is a diagram showing a current and electric polarization that occur when applying an alternating external magnetic field. Is a diagram showing the crystal structure and magnetic structure of multiferroic solid is a material BaFe _10.4 Sc _1.6 O ₁₉ of the present invention. FIG. 3 is a conical spiral structure diagram of a spin of −23 ° C. or lower of BaFe _10.4 Sc _1.6 O ₁₉ which is a multiferroic solid material according to the present invention. Is a diagram showing temperature dependence of BaFe _10.4 Sc _1.6 O ₁₉ magnetization is multiferroic solid material according to the present invention. A single crystal of BaFe _10.4 Sc _1.6 O ₁₉ a multiferroic solid state material of the present invention is a photograph alternative to a drawing showing.

Explanation of symbols

1,11,21,31 Multiferroic solid material 2,12,22,32 Metal electrode 3,13 Wiring 4 Electrical equipment 5 AC magnetic field 6 Displacement current 14 Voltmeter 15 Perpendicular magnetic recording material 23 Multiferroic memory cell 24 bit Line 25 Word line 33 Magnetic field applied from outside 34 Direction of generated electric polarization 35 Ammeter

Claims (9)

  It is made of a multiferroic solid material having both ferroelectricity and ferromagnetism made of M (magnetoprambite) ferrite, and an electric field is induced by applying an external magnetic field to the multiferroic solid material. Multiferroic electronic device.   Made of M (ferroplumbite) type ferrite, which is a multiferroic solid material that combines ferroelectricity and ferromagnetism, and controls the strength and direction of electric polarization by applying an external magnetic field to the multiferroic solid material. A multiferroic electronic device characterized by that. 3. The multiferroic electronic device according to claim 1, wherein the multiferroic solid material is M-type ferrite of AFe ₁₂ O ₁₉ , and A is Ca, Ba, Sr, Pb, or these two kinds of elements. A multiferroic electronic device characterized by being an element composed of a mixture. 3. The multiferroic electronic device according to claim 1, wherein the multiferroic solid material is AFe _12-x B _x O ₁₉ M-type ferrite, and A is Ca, Ba, Sr, Pb, or two types thereof. A multiferroic electronic device, wherein B is a trivalent element made of rare earth such as Sc, Y, Ac, Ce, Pr, and the range of x is 0 <x ≦ 2. . 3. The _multiferroic electronic device according to claim 1, wherein the multiferroic solid material is AFe _12-2x B _x C _x O ₁₉ M-type ferrite, and A is Ca, Ba, Sr, Pb, or these. B is a tetravalent element such as Ti and Zr, C is a divalent element composed of Mg, Zn, Co, Ni, and Cu, and the range of x is 0 <x ≦ 3 is a multiferroic electronic device. 3. The multiferroic electronic device according to claim 1, wherein the multiferroic solid material is M-type ferrite of AFe _12-xy B _x C _y O ₁₉ , and A is Ca, Ba, Sr, Pb, or these B is a trivalent element made of rare earth such as Sc, Y, Ac, Ce, Pr, etc. C is a divalent element made of Mg, Zn, Co, Ni, Cu , X is 0 <x ≦ 2, and y is 0 <y ≦ 1, a multiferroic electronic device. 3. The _multiferroic electronic device according to claim 1, wherein the multiferroic solid material is M-type ferrite of AFe _12-2x-y B _x C _x D _y O ₁₉ , wherein A is Ca, Ba, Sr. , Pb or a mixture of these two elements, B is a tetravalent element such as Ti and Zr, C is a divalent element composed of Mg, Zn, Co, Ni and Cu, and D is also Mg, A multiferroic electronic device, which is a divalent element composed of Zn, Co, Ni, and Cu, wherein x ranges from 0 <x ≦ 3 and y ranges from 0 <y ≦ 1.   3. The multiferroic electronic device according to claim 1, wherein the multiferroic solid material is grown as a single crystal by a floating melting zone single crystal growth method using a light lamp in a high-pressure gas atmosphere of an oxygen gas atmosphere of 2 atm or higher. A multiferroic electronic device characterized by that.   3. The multiferroic electronic device according to claim 1, wherein the multiferroic solid material is further subjected to heat treatment in a range of 400 ° C. to 1000 ° C. in a range of 100 to 400 hours in oxygen, and a helical magnetic transition temperature. A multiferroic electronic device characterized in that the temperature is increased to 400K.