KR101368298B1 - a device for generating high frequency microwave and high frequency magnetic field using spin transfer torque - Google Patents

Abstract

Provided are a high frequency microwave generating device and a high frequency magnetic field generating device using spin transfer torque phenomenon.
The high frequency microwave generating device according to the present invention has a structure consisting of a fixed magnetic layer / nonmagnetic layer / free magnetic layer / nonmagnetic layer / sensing magnetic layer / anti-ferromagnetic layer, the free magnetic layer is a first thin film and a first magnetic material containing a soft magnetic material A second thin film made of a second material having a magnetic anisotropy constant (K), wherein the fixed magnetic layer has a magnetization characteristic in a vertical direction of the thin film, and the sensing magnetic layer has a magnetization characteristic in a horizontal direction of the thin film, The high frequency microwave generating device according to the present invention is capable of magnetizing rotation even at a higher current. Therefore, since the high frequency device according to the present invention can generate a high frequency AC signal, according to the development of devices such as a resonator, oscillator, band-path filter, and the like driven in the high frequency region, more information is transmitted at a faster time than the conventional device. And processing, it is possible to increase the efficiency of the device.

Description

High frequency microwave and high frequency magnetic field using spin transfer torque

The present invention relates to a high frequency microwave and high frequency magnetic field generating device using spin transfer torque phenomenon, and more particularly, to generate a high frequency microwave and high frequency magnetic field capable of generating an electric signal and an alternating magnetic field of a much higher frequency than the prior art. It relates to an element.

Magnetic material refers to a material that is spontaneously magnetized even if external magnetic field is not applied. Particularly, in the spin valve structure in which the first magnetic material (fixed magnetic layer) / nonmagnetic material / second magnetic material (free magnetic layer) is sequentially stacked, the relative magnetization directions of the fixed magnetic layer and the free magnetic layer, for example, are parallel or antiparallel to each other. Therefore, a large magnetoresistance effect occurs in which the electrical resistance varies. This giant magnetoresistance effect means that the relative magnetization direction can control the current, and the relative magnetization direction can be adjusted by flowing a current according to Newton's third law of action-reaction. Therefore, a device for inverting and rotating the magnetization of the free magnetic layer by applying a current to the spin valve structure is proposed by IBM and proved experimentally. In this case, this is because the current spin-polarized by the first magnetic body transmits its spin angular momentum while passing through the second magnetic body, which is called spin-transfer torque.

In order to effectively rotate the magnetization, a structure in which the magnetization direction of the pinned magnetic layer is perpendicular to the thin film surface has been proposed. In this structure, the spin polarization direction of the current polarized by the pinned magnetic layer has the same vertical direction as that of the pinned magnetic layer. The spin transfer torque of spin-polarized current causes magnetization rotation by current injection, and as the current increases, the magnetization rotation frequency increases and at the same time the vertical component of free magnetic layer magnetization increases, so that the horizontal component of free magnetic layer magnetization decreases. . As a result, magnetization rotation no longer occurs when the magnetization of the free magnetic layer is completely saturated at a sufficiently large current.

By using the high-speed magnetization rotation by the spin transfer torque, two application elements are possible. The first application device is a high frequency AC signal electronic device that can be used for communication and logic devices in the high frequency region.

1 is a cross-sectional view showing the structure of a high frequency AC signal electronic device according to the prior art.

Referring to FIG. 1, a high frequency AC signal electronic device basically includes a first magnetic material 100 (fixed magnetic layer) / nonmagnetic material 101 / a second magnetic material 102 that rotates at high speed by a current having free magnetization in a vertical direction. Magnetic layer) / nonmagnetic material 103 / a third magnetic material 104 (sensing layer) / antiferromagnetic layer 108 having a magnetization in the horizontal direction for signal detection. At this time, the sensing layer has a structure of the magnetic layer 1 (105) / the nonmagnetic material 106 / the magnetic layer 2 (107), which is the magnetic layer 1 (105) and the magnetic layer by RKKY interaction through the non-magnetic material 106, such as Ru The magnetization directions of the two (107) are opposite to each other, so that the leakage magnetic field generated from the entire sensing layer 104 and applied to the free magnetic layer 102 becomes almost zero, so as not to prevent free magnetization rotation of the free magnetic layer magnetization. do. In addition, the antiferromagnetic layer 108 provides an exchange bias to fix the magnetization direction of the magnetic layer 2 (107) of the sensing layer in one direction. Therefore, when the magnetization of the free magnetic layer rotates at high speed by the application of current, the angles of the free magnetic layer magnetization and the sensing layer magnetization change with time. As a result, the resistance changes with time due to the large magnetoresistance effect, thereby generating a high frequency AC signal. It is possible to let.

The second application element is a high frequency magnetic field generating element which can be used for a computer hard disk which is a high density information storage element. In order to increase the recording density of the hard disk, the size of the crystalline grains of the magnetic recording medium should be reduced. This is because the signal-to-noise ratio (SNR) is larger as the number of grains in a unit recording bit increases. However, if the grain size is reduced in this way, the superparamagnetism limit, that is, the magnetization direction recorded by the thermal energy at room temperature is changed within a certain time, that is, the problem that the recorded magnetic information is undesirably erased. The time t during which the magnetization direction is maintained on average on the basis of resistance to heat energy may be represented by Equation 1 below.

In the above formula, f ₀ is about 1 GHz at trial frequency, K is the magnetic anisotropy constant of the recording medium, V is the volume of grain, k _B is Boltzmann constant (= 1.381x10 ^-16 erg / K), and T is the Kelvin temperature. .

It can be seen from Equation 1 that when the size (V) of the grains is reduced for high-density magnetic recording, K must be increased to maintain the time (t) at a commercially available value. However, the magnitude of the magnetic field required for recording desired magnetic information on the magnetic recording medium is proportional to the anisotropic magnetic field H _k (= 2K / Ms, where Ms is the amount of saturation magnetization of the magnetic recording medium). In other words, as the size of the crystal grains is reduced, a higher K is required, and as a result, the size of the magnetic field required for recording increases. Since the maximum magnetic field that can be created by using existing recording heads in the current hard disk is limited, a method of effectively recording a magnetic recording medium having a high H _k is required to obtain a higher recording density. Recently, Professor Zhu et al. Of Carnegie Mellon University proposed a method to effectively reduce the size of the total magnetic field required for recording by applying a high frequency modulated magnetic field simultaneously in addition to the magnetic field generated from the recording head (J.-G. Zhu, X. Zhu, and Y. Tang, IEEE Trans.Mag. 44 , 125 (2008)). In this method, the free magnetic layer magnetization rotates at high speed by the spin transfer torque. When the frequency of the alternating magnetic field is close to the resonance frequency of the magnetization of the recording medium, the magnetic recording medium is recorded with a magnetic field lower than the original H _k. It is possible to. At this time, it is very important to sufficiently obtain the rotation frequency according to the magnetization of the free magnetic layer, and the rotation frequency is proportional to the magnitude of the current. However, when the current is increased to obtain a large rotation frequency, the magnetization of the free magnetic layer gradually increases in the vertical direction of the thin film, and as a result, there is a problem that the magnetization rotation is no longer performed above a certain level of the threshold current.

Accordingly, an object of the present invention is to provide a high frequency microwave and a high frequency magnetic field generating device having a high threshold current and, as a result, large magnetization rotation.

In order to solve the above problems, the present invention is a structure comprising a fixed magnetic layer / first nonmagnetic layer / free magnetic layer / second nonmagnetic layer / sensing magnetic layer / antiferromagnetic layer, the free magnetic layer includes a soft magnetic first material A second thin film comprising a first thin film and a second material having a negative magnetic anisotropy constant (K), wherein the pinned magnetic layer has a magnetization characteristic in a vertical direction of the thin film, and the sensing magnetic layer is in a horizontal direction of the thin film. Provided is a high frequency microwave generating device having a magnetization characteristic of. In addition, the present invention is a structure comprising a fixed magnetic layer / nonmagnetic layer / free magnetic layer, the free magnetic layer comprises a first thin film comprising a soft magnetic first material, and a second material having a negative magnetic anisotropy constant (K) And a second thin film, wherein the pinned magnetic layer has a magnetization characteristic in a vertical direction with respect to the thin film, and the sensing magnetic layer has a magnetization in a horizontal direction of the thin film. Furthermore, the present invention is a structure comprising a first pinned magnetic layer / free magnetic layer / a second pinned magnetic layer, the free magnetic layer has a first thin film comprising a soft magnetic first material and a negative magnetic anisotropy constant (K) A second thin film comprising a second material, wherein the first pinned magnetic layer has a magnetization characteristic in the vertical direction of the thin film, and the second pinned magnetic layer has a magnetization characteristic in the vertical direction of the thin film. Provided is an element.

In one embodiment of the present invention, the pinned magnetic layer is a multilayer thin film of (X / Y) _n structure (n≥1), wherein X and Y are Fe, Co, Si, Zr, Ni, B, Si, Zr, Pt , Pd and a mixture thereof, and the sensing magnetic layer has an artificial diamagnetic structure of the first magnetic layer / nonmagnetic layer / second magnetic layer, wherein the first magnetic layer and the second magnetic layer are Fe, Co, Ni. , B, Si, Zr, and any one thereof, and the nonmagnetic layer of the sensing magnetic layer is one selected from Ru, Cu, Al, Ta, Au, Ag, and mixtures thereof.

In another embodiment of the present invention, the first material is any one selected from Fe, Co, Ni, B, Si, Zr, and mixtures thereof, and the second material is CoFe, α-FeC having a double hcp structure. , MnSb, CoIr and mixtures thereof. Furthermore, the antiferromagnetic layer is made of any one selected from Ir, Pt, Mn, and mixtures thereof, and the magnetic anisotropic magnetic field H _k1 of the first pinned magnetic layer is different from the magnetic anisotropic magnetic field H _k2 of the second pinned magnetic layer.

In addition, the high-frequency mipro wave generation device and the high-frequency magnetic field generating device according to the present invention is in-plane It is circular. In one embodiment of the present invention, the first nonmagnetic layer and the second nonmagnetic layer are made of any one selected from Ru, Cu, Al, Ta, Au, Ag, AlO _x , MgO, TaO _x , ZrO _x, and mixtures thereof. In this case, the first nonmagnetic layer and the second nonmagnetic layer may be different materials.

In the high frequency microwave generating element and the high frequency magnetic field generating element according to the present invention, the free magnetic layer has a structure in which a second thin film is inserted into the first thin film, or a second thin film is laminated on one side or both sides of the first thin film. It may be a structure.

H_K이고 (이때

(=1.76x10⁷Oe^-1s^-1)는 자이로마그네틱 상수), H_K는 K에 비례하기 때문에, 보다 높은 K를 갖는 자기기록매체에 자기정보를 기록할 수 있게 되므로, 자기결정립의 크기를 기존 기술에 비해 더 작게 만들어도 열적 안정성에 문제가 없게 되며, 결과적으로 보다 높은 기록밀도를 갖는 하드디스크 제조가 가능해진다.The high frequency microwave generating device according to the present invention is capable of magnetizing rotation even at a higher current. Therefore, the device according to the present invention can generate a high frequency AC signal, and according to the development of devices such as a resonator, oscillator, band-path filter that is driven in such a high frequency region, and transmits more information and faster than conventional devices Since it can process, the efficiency of an element can be increased. In addition, when a device operating in a higher frequency range is developed in view of a high frequency magnetic field device for a computer hard disk, the resonance frequency of the magnetic recording medium is increased.

H _K (where

(= 1.76x10 ⁷ Oe ^-1 s ^-1 ) is a gyro magnetic constant), and since H _K is proportional to K, magnetic information can be recorded on a magnetic recording medium having a higher K. Making it smaller than the conventional technology does not cause thermal stability problems, and as a result, it is possible to manufacture a hard disk with a higher recording density.

1 is a cross-sectional view showing the structure of an electronic device for generating a high frequency using a conventional spin transfer torque.
2 is a cross-sectional view showing the structure of a high frequency device using spin transfer torque according to an embodiment of the present invention.
3 is a cross-sectional view showing the structure of a high frequency device using spin transfer torque according to another embodiment of the present invention.
4 is a cross-sectional view showing the structure of a high frequency device using spin transfer torque according to another embodiment of the present invention.
Figure 5 is a graph measuring the frequency characteristics and in-plane magnetization component according to the current of the conventional device.
Figure 6 is a graph measuring the frequency characteristics and in-plane magnetization components according to the current of the high-frequency device according to an embodiment of the present invention.
7 is a graph showing the frequency characteristics and in-plane magnetization components of a high frequency device according to another embodiment of the present invention.

As described above, the present invention provides a high frequency microwave generating element and a high frequency magnetic field generating element capable of magnetizing rotation even at a higher current. In the present invention, the magnetizing rotation is superior to the conventional technology by increasing the threshold current value of the free magnetic layer. A high frequency microwave generating element and a high frequency magnetic field generating element are achieved. That is, as described above, the rotation frequency according to the free magnetic layer magnetization is proportional to the magnitude of the current, and when the magnetization of the free magnetic layer is completely saturated in the vertical direction of the thin film by the current, that is, spin transfer torque, the magnetization rotation is no longer performed. . Therefore, the present inventors have come to the present invention based on the fact that in order to generate a high frequency signal and a magnetic field, it is necessary to increase the value of the threshold current that the free magnetic layer magnetization saturates in the vertical direction of the thin film. This is accomplished by inserting a magnetic body having a negative magnetic anisotropy constant K into the magnetic layer.

The magnetic anisotropy energy of the magnetic body may be represented by Equation 2 below.

Θ in the above equation is the angle between the easy axis of magnetization and the magnetization direction of the magnetic body.

In the general application device described above, the biaxial axis for magnetization of the free magnetic layer is in the in-plane direction of the thin film. Therefore, the magnetic anisotropy constant K is adding or inserting a material having a negative value on the free magnetic layer θ = 0, that is, the magnetic anisotropy energy, when the magnetization direction is in-plane direction is at least effectively prevented from occurring a vertical component of magnetization Can be.

Substances having such negative K values include CoFe, α-FeC, NiAs-typed MnSb, hcp CoIr, etc. having a double hcp structure (M. Takahashi and S. Kadowaki, J. Phys. Soc. Jpn. 48, 1391 (1980); M. Thkahashi, Y. Takahashi, and H. Shoji, IEEE Trans.Magn. 37 , 2179 (2001); N. Kikuchi et al ., J. Phys. Condens. Matter 11 , L485 (1999); T. Oikawa et al ., IEEE Trans. Magn. 38 , 1976 (2002). The double hcp structure will be described in more detail. When dividing the arrangement pattern of one layer of atoms into A, B, and C, the fcc structure is formed by ABCABC... Sequence and common hcp is ABAB… In contrast to the order, the dual hcp structure used in one embodiment of the present invention is ABAC... It is a structure that is distinguished from fcc and hcp in order. However, the present invention is not limited to the above-described materials, and any material can be applied to the microwave generating device according to the present invention as long as it has a negative magnetic anisotropy constant, which is also within the scope of the present invention.

2 is a cross-sectional view showing the structure of a high frequency microwave generating device according to an embodiment of the present invention.

Referring to FIG. 2, the high-frequency microwave generating device according to the embodiment of the present invention basically has a high speed by using a first magnetic material 200 (fixed magnetic layer) / first nonmagnetic material 201 / current having vertical magnetization. Is composed of a second magnetic material (202: free magnetic layer) / second non-magnetic material (203) / a third magnetic material (204: sensing magnetic layer) / anti-ferromagnetic layer (210) having a magnetization in the horizontal direction for signal detection The free magnetic layer 202 is composed of a first thin film 205 made of a soft magnetic material having a large spin polarization rate and a small magnetic anisotropy that can be easily rotated, and a negative magnetic anisotropy constant for maximizing spin transfer torque and a detection signal. And a second thin film 206 of a material having a value of K). In particular, FIG. 2 discloses a structure in which the free magnetic layer has a second thin film 206 inserted into the first thin film 205, but this is only an example, and the second thin film 206 is one side of the first 205. Or laminated on both sides, and may have a structure of a first thin film / second thin film, a second thin film / first thin film, a second thin film / first thin film / second thin film, which is also within the scope of the present invention. Belong. That is, the second thin film 206 made of a material having a negative magnetic anisotropy constant (K) value may be inserted into the first thin film 205 made of a material having a high spin polarization rate, or the first thin film may be placed in the center of the first thin film. It may be located on either or both sides of one thin film.

The constituent material of the first thin film may be any one or more selected from Fe, Co, Ni, B, Si, Zr, and a mixture thereof, which enables a large spin polarization rate and easy rotation. However, the present invention is not limited thereto, and any material may be used as the first material as long as it has a large spin polarization rate and easy rotation, which is also within the scope of the present invention. In addition, any material may be used as long as it has a negative magnetic anisotropy constant as described above as the material of the second thin film.

The pinned magnetic layer is a multilayer thin film having a (X / Y) _n structure (n ≧ 1), and X and Y are thin films made of any one selected from Fe, Co, Ni, B, Si, Zr, Pt, Pd, and mixtures thereof. Can be. In addition, the sensing magnetic layer 204 has a structure of the first magnetic layer 207 / nonmagnetic material 208 / second magnetic layer 209, similar to the existing structure, wherein the nonmagnetic material 208 such as Ru The magnetization directions of the magnetic layer 207 and the magnetic layer 209 are reversed by the RKKY interaction, so that the leakage magnetic field generated from the entire sensing layer 204 and applied to the free magnetic layer 202 becomes almost zero. Do not interfere with the free magnetization of the magnetic layer magnetization. In this case, the first magnetic layer 207 and the second magnetic layer 209 of the sensing magnetic layer 204 is made of any one selected from Fe, Co, Ni, B, Si, Zr and mixtures thereof, and the nonmagnetic layer of the sensing magnetic layer 208 may be made of any one selected from Ru, Cu, Al, Ta, Au, Ag, and mixtures thereof.

In addition, the anti-ferromagnetic layer 210 provides an exchange bias to fix the magnetization direction of the magnetic layer 209 of the sensing magnetic layer in one direction.

Furthermore, in one embodiment of the present invention, the first nonmagnetic material 201 and the second nonmagnetic material 203 may be formed of a metal having high electrical conductivity. When the total resistance of the device is low, more than the same applied voltage may be used. This is because a positive current flows to enable a high power device. For example, a material having a great electrical conductivity such as Ru, Cu, Al, Ta, Au, Ag, or the like may be used as a constituent material of the first nonmagnetic material 201 and the second nonmagnetic material 203. In addition, when a material having a significantly low electrical conductivity is used for the nonmagnetic material, the current decreases under the same voltage, but the difference in the magnetoresistance due to the magnetization rotation becomes very large due to the tunneling effect of the electrons. Thus, the nonmagnetic material 201 and the nonmagnetic material Materials having significantly low electrical conductivity may also be used for one or both of (203), and oxides such as AlO _x , MgO, TaO _x , and ZrO _x may be used. Therefore, different materials having different electrical conductivity may be used for the first nonmagnetic material 201 and the second nonmagnetic material 203.

3 is a cross-sectional view showing the structure of a high frequency magnetic field generating device according to another embodiment of the present invention.

In the case of the high frequency magnetic field generating device according to FIG. 3, it is not necessary to detect an electric signal using the giant magnetoresistive effect, and thus, in the structure disclosed in FIG. 2, a third magnetic material having horizontal magnetization for signal detection may be used. Sensing layer) / antiferromagnetic layer 210 '.

Furthermore, since the high frequency magnetic field generating device does not need to detect the electric signal using the giant magnetoresistive effect, another embodiment of the present invention can provide a simpler thin film stacked structure than the above structure, which is illustrated in FIG. Shown.

4 is a cross-sectional view showing the structure of a high frequency microwave generating device according to another embodiment of the present invention.

Referring to FIG. 4, the high frequency microwave generating device according to the embodiment includes a first magnetic material having vertical magnetization, that is, a first magnetic layer 300 / a free magnetic layer 301 rotating at high speed by a current. The second magnetic material having a vertical magnetization, that is, the second fixed magnetic layer 302, and the free magnetic layer 301 that rotates at high speed by current, maximizes the spin transfer torque and the detection signal as in a high frequency electronic device. For this purpose, the first thin film 303 comprising a soft magnetic material having a small spin anisotropy for high spin polarization and easy rotation, and the second thin film 304 including a material having a negative magnetic anisotropy constant (K) value. It has a laminated structure. However, such a structure is only an example, and the first thin film 303 made of a material having a high spin polarization rate is inserted or positioned on either side with the second thin film 304 made of a material having a negative K value. can do.

In the above structure, the first pinned magnetic layer 300 and the second pinned magnetic layer 302 having the perpendicular magnetic anisotropy on both sides of the free magnetic layer prevent the magnetic walls existing in the free magnetic layer from escaping in either direction of the device by current. It acts as a potential well.

The first or second pinned magnetic layer is a multilayer thin film structure of (X / Y) _n structure (n ≧ 1) as described above, wherein X and Y are Fe, Co, Ni, B, Si, Zr, Pt. , Pd and a mixture thereof may be a thin film made of any one.

In addition, in order to form a magnetic wall in the free magnetic layer, the magnetic anisotropy field H _k1 of the first magnetic body 300 and the magnetic anisotropy field H _k2 of the third magnetic body 302 must be different from each other. For example, when H _k1 is larger than H _k2 , a magnetic field larger than H _k1 is first applied from the outside to align the magnetization of the first magnetic body and the third magnetic body in one vertical direction, and then another larger than H _k2 and smaller than H _k1. When another external magnetic field is applied in the opposite direction, the magnetization direction of the first magnetic body and the magnetization direction of the third magnetic body can be made to be opposite to each other, and as a result, a magnetic wall is formed in the second magnetic layer. When current is applied in this situation, the magnetic domain wall rotates at high speed by spin transfer torque, and as a result, a high frequency magnetic field is formed outside.

Since the structure is a simple structure compared to the above-described structure, it is possible to achieve the effect of cost reduction during manufacture.

Since the high frequency microwave generating device according to the present invention has to fabricate a structure as small as possible in order to obtain a high current density, a patterning process is required. At this time, in-plane magnetic shape anisotropy is the same in any direction, so that the in-plane shape of the manufactured structure should be as close to the circle as possible in order to facilitate high-speed rotation of magnetization.

Numerical simulation results using the kinetic equation of magnetization are disclosed to confirm the effect of the high frequency microwave generation device according to the present invention. The validity of this method has been confirmed by various studies in developing spin transfer torque and computer hard disk, and the equation of motion of magnetization by current is shown in Equation 3 below.

은 자화벡터,

는 자이로마그네틱 상수,

는 모든 유효자기장벡터, α는 Gilbert 감쇠상수이며, α_J는 비자성체를 사이에 둔 두 자성체 사이에 유기되는 스핀전달토크로 At this time,

Silver Magnetized,

Is a gyromagnetic constant,

Is the effective magnetic field vector, α is the Gilbert damping constant, and α _J is the spin transfer torque induced between two magnetic bodies with nonmagnetic materials in between.

이며,

는 Planck 상수를 2π로 나눈 값이고, e (=1.6×10^-19 C)는 전자의 전하양,

는 물질 및 전체 구조에 의해 결정되는 스핀분극효율 상수, I는 전류, Ms는 자성체의 포화자화양, x는 막에 수직방향이며,

는 비자성체로부터 자성층으로 입사하는 스핀분극전류의 스핀방향의 단위 벡터로 x와 동일한 방향이다. 또한 b_J는 비자성체 없이 자화가 자성체 내에서 연속적으로 변하는, 예를 들면 자벽 구조에 발생하는 스핀전달토크의 크기로

이며, P는 물질 자체에 의해 결정되는 자성체의 스핀분극율로 0~1 사이의 값을 갖으며, μ_B(=9.274×10^-24 J/T)는 Bohr magneton, J는 전류밀도이다.

Lt;

Is the Planck constant divided by 2π, e (= 1.6 × 10 ^-19 C) is the charge of the electron,

Is the spin polarization efficiency constant determined by the material and the overall structure, I is the current, Ms is the amount of saturation magnetization of the magnetic body, x is the direction perpendicular to the film,

Is a unit vector of the spin direction of the spin polarization current incident on the magnetic layer from the nonmagnetic material and is the same direction as x. And b _J is the amount of spin transfer torque that occurs in a magnetic wall structure in which magnetization continuously changes in the magnetic material without a nonmagnetic material.

P is a spin polarization rate of the magnetic body determined by the material itself, and has a value between 0 and 1, μ _B (= 9.274 x 10 ^-24 J / T) is the Bohr magneton and J is the current density.

Hereinafter, the excellent effect of the microwave generating element according to the present invention will be described in more detail as an experimental example.

Comparative Example

Frequency measurement according to the current of the device according to the prior art

FIG. 5 is a graph illustrating a frequency magnitude according to a current and a magnitude of a horizontal component in a conventional structure in which a high frequency AC signal electronic device according to the related art disclosed in FIG. 1, that is, a material having a negative K in a free magnetic layer does not exist.

The structure and property values used are as follows.

= 1225nm ^2, the cross-sectional area of the entire structure of the first magnetic body (pinned magnetic layer: Thickness t = 50nm, the perpendicular anisotropy constant ^{K = + 10 7 erg / cm} 3, saturation magnetization Hwayang M _S = 1000emu / cm ^3, the exchange constant A = 10 ^{- 6} erg / cm, Gilbert attenuation constant = 0.05, spin polarization rate P = 0.2) / nonmagnetic material (t = 10nm) / second magnetic material rotating at high speed by current (free magnetic layer: thickness t = 10nm, vertical anisotropy constant K = 0, saturation magnetization M _S = 1600emu / cm ³ , exchange constant A = 10 ^-6 erg / cm, Gilbert damping constant = 0.01, spin polarization rate P = 0.7, spin polarization efficiency constant = 0.7) / nonmagnetic material (t = 10 nm) / third magnetic material with horizontal magnetization for signal detection (sensing layer: same as free magnetic layer).

Referring to FIG. 5, it can be seen that in the conventional structure according to the prior art, the maximum high frequency microwave generation device can obtain a frequency of about 16.8 GHz.

Experimental Example  One

In the present experimental example, except that a material having a negative K was inserted into the free magnetic layer, the frequency magnitude according to the current and the magnitude of the horizontal component were measured under the same conditions as in Comparative Example 1. At this time, a negative magnetic anisotropy constant, i.e., a material (CoIr) having a negative K (= -10 ⁷ erg / cm ³ ), has a thickness t = 10 nm, a vertical anisotropy constant K = -10 ⁷ erg / cm ³ , and a saturation magnetization M _S = 1000 emu / cm ³ , exchange constant A = 10 ^-6 erg / cm, Gilbert attenuation constant = 0.05, spin polarization ratio P = 0.2 were inserted.

6 is a graph showing the results according to the present experimental example.

Referring to FIG. 6, although the device according to the present invention has the same structure, a frequency of up to 50.2 GHz may be obtained by inserting a material having a negative magnetic anisotropy constant into a free magnetic layer, which is Comparative Example 1 This is much higher than 16.8 GHz.

Experimental Example  2

FIG. 7 is a graph illustrating the magnitude of the frequency and the horizontal component according to the current in the structure disclosed in FIG. 4, that is, a material having a negative K in the free magnetic layer and excluding the nonmagnetic layer.

The device structure used in this experimental example is a first magnetic material having a magnetization in the vertical direction (thickness t = 20nm, vertical anisotropy constant K = + 10 ⁸ erg / cm ³ , saturation magnetization M _S = 1000emu / cm ³ , exchange constant A = 10 ^-6 erg / cm, Gilbert attenuation constant = 0.05, spin polarization rate P = 0.2) / 2-1 magnetic material having a negative K and rotating at high speed by current (thickness t = 5nm, perpendicular anisotropy constant) K = -10 ⁸ erg / cm ³ , saturation magnetization M _S = 1000emu / cm ³ , exchange constant A = 10 ^-6 erg / cm, Gilbert damping constant = 0.05, spin polarization rate P = 0.2) 2-2 magnetic material rotating with thickness (t = 5nm, perpendicular anisotropy constant K = 0erg / cm ³ , saturation magnetization M _S = 1600emu / cm ³ , exchange constant A = 10 ^-6 erg / cm, Gilbert damping constant = 0.01, spin polarization rate P = 0.7) / third magnetic material having a negative K and rotating at high speed by current (same as 2-1 magnetic material) / third magnetic material having a vertical magnetization (H _K Same as the first magnetic body except 90% of the first magnetic body) The.

Referring to FIG. 7, the microwave generating device according to the present experimental example can also obtain a frequency of up to about 59.1 GHz, which is an excellent frequency compared to the device according to the prior art.

Through the above experimental example, it can be seen that by inserting a material having a negative magnetic anisotropy constant into the free magnetic layer, it is possible to obtain an electrical signal and an alternating magnetic field of a much higher frequency than the existing structure. However, all of the above-described experimental examples are only for better understanding of the present invention, and the present invention is not limited or limited by the experimental conditions, materials, etc. used in the above-described experimental examples.

Claims (20)

A structure including a pinned magnetic layer, a first nonmagnetic layer, a free magnetic layer, a second nonmagnetic layer, a sensing magnetic layer, and an antiferromagnetic layer,
The free magnetic layer comprises a first thin film comprising a soft magnetic first material and a second thin film comprising a second material having a negative magnetic anisotropy constant (K),
The pinned magnetic layer has a magnetization characteristic in the vertical direction of the thin film, and
The sensing magnetic layer has a magnetization characteristic in the horizontal direction of the thin film,
The free magnetic layer has a magnetization characteristic of the direction of continuous rotation,
The second thin film has a structure inserted into the first thin film or the second thin film has a structure laminated on one side or both sides of the first thin film,
And the second material has a double hcp structure. It is a structure including a fixed magnetic layer, a nonmagnetic layer, a free magnetic layer,
The free magnetic layer comprises a first thin film comprising a soft magnetic first material and a second thin film comprising a second material having a negative magnetic anisotropy constant (K),
The pinned magnetic layer has a magnetization characteristic in a direction perpendicular to the thin film, and
The sensing magnetic layer has a magnetization characteristic in a horizontal direction of the thin film, and the free magnetic layer has a magnetization characteristic in a direction in which it continuously rotates.
The second thin film has a structure inserted into the first thin film or the second thin film has a structure laminated on one side or both sides of the first thin film,
And said second material has a double hcp structure. A structure including a first pinned magnetic layer, a free magnetic layer, and a second pinned magnetic layer,
The free magnetic layer comprises a first thin film comprising a soft magnetic first material and a second thin film comprising a second material having a negative magnetic anisotropy constant (K),
The first pinned magnetic layer has a magnetization characteristic in the vertical direction of the thin film, and
The second pinned magnetic layer has a magnetization characteristic in the vertical direction of the thin film,
The free magnetic layer has a magnetization characteristic of the direction of continuous rotation,
The second thin film has a structure inserted into the first thin film or the second thin film has a structure laminated on one side or both sides of the first thin film,
And the second material has a double hcp structure. The method of claim 1,
The pinned magnetic layer is a multilayer thin film (n ≧ 1) in which n double layers composed of X and Y layers are stacked, wherein X and Y are Fe, Co, Ni, B, Si, Zr, Pt, Pd, and High frequency microwave generation device, characterized in that the thin film made of any one selected from a mixture thereof. 4. The method according to claim 2 or 3,
The pinned magnetic layer is a multilayer thin film (n ≧ 1) in which n double layers composed of X and Y layers are stacked, wherein X and Y are Fe, Co, Ni, B, Si, Zr, Pt, Pd, and High frequency magnetic field generating device, characterized in that the thin film made of any one selected from a mixture thereof. The method of claim 1,
The sensing magnetic layer is a first magnetic layer, A nonmagnetic layer and a second magnetic layer, wherein the first magnetic layer and the second magnetic layer is any one selected from Fe, Co, Ni, B, Si, Zr and mixtures thereof, the nonmagnetic layer of the sensing magnetic layer is Ru, Cu , Al, Ta, Au, Ag, and a high frequency microwave generating device, characterized in that made of any one selected from a mixture thereof. The method of claim 1,
The first material is any one selected from Fe, Co, Ni, B, Si, Zr and mixtures thereof. 4. The method according to claim 2 or 3,
The first material is any one selected from Fe, Co, Ni, B, Si, Zr and mixtures thereof. The method of claim 1,
The second material is any one selected from CoFe, α-FeC, MnSb, CoIr, and a mixture thereof having a double hcp structure. 4. The method according to claim 2 or 3,
The second material is a high frequency magnetic field generating device, characterized in that any one selected from CoFe, α-FeC, MnSb, CoIr and a mixture thereof having a double hcp structure. The method of claim 1,
The antiferromagnetic layer is a high frequency microwave generating device, characterized in that consisting of any one selected from Ir, Pt, Mn and mixtures thereof. The method of claim 3, wherein
The magnetic anisotropic magnetic field H _k1 of the first pinned magnetic layer is different from the magnetic anisotropic magnetic field H _k2 of the second pinned magnetic layer. The method of claim 1,
The in-plane shape of the high frequency microwave generating element A high frequency microwave generating element, characterized by being circular. 4. The method according to claim 2 or 3,
The in-plane shape of the high frequency magnetic field generating element A high frequency magnetic field generating element, characterized by being circular. The method of claim 1,
The first nonmagnetic layer and the second nonmagnetic layer comprise any one selected from Ru, Cu, Al, Ta, Au, Ag, AlO _x , MgO, TaO _x , ZrO _x, and mixtures thereof. . 16. The method of claim 15,
The high frequency microwave generating device according to claim 1, wherein the first nonmagnetic layer and the second nonmagnetic layer are made of different materials. The method of claim 1,
And the free magnetic layer has a structure in which a second thin film is inserted into the first thin film. The method of claim 1,
The free magnetic layer has a structure in which the second thin film is laminated on one side or both sides of the first thin film. 4. The method according to claim 2 or 3,
And the free magnetic layer has a structure in which a second thin film is inserted into the first thin film. 4. The method according to claim 2 or 3,
The free magnetic layer has a structure in which a second thin film is laminated on one side or both sides of the first thin film.

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