JP2018121150A - Filter device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a filter device using a magnetoresistance effect element, capable of operating as a practical bandpass filter.SOLUTION: A filter device 1 includes magnetoresistance effect element 2, an input port 3 to which a high frequency input signal is applied, an output port 4 where a high frequency output signal appears, and an energy imparting section 5. The magnetoresistance effect element 2 includes a first magnetization free layer 21 having first magnetization, and a second magnetization free layer 23 having second magnetization. Ferromagnetic resonance frequencies of the first magnetization free layer 21 and the second magnetization free layer 23 are different from each other. The energy imparting section 5 imparts energy for generating oscillation based on the high frequency input signal in the first magnetization and the second magnetization to the magnetoresistance effect element 2. The high frequency output signal is resulting from oscillation of the first magnetization and the second magnetization.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a filter device using a magnetoresistive effect element.

  In recent years, with the enhancement of functions of mobile communication devices such as mobile phones, the speed of wireless communication has been increased. Since the communication speed is proportional to the bandwidth of the frequency band to be used, the number of frequency bands necessary for communication increases, and accordingly, the number of high-frequency filters such as bandpass filters mounted on mobile communication devices also increases. ing.

  On the other hand, in recent years, spintronics has attracted attention as a technology that can be applied to high-frequency devices such as high-frequency filters. One technique that has attracted particular attention in spintronics is a technique using ferromagnetic resonance. The magnetization of a ferromagnetic material placed in a magnetic field can oscillate such that the direction of magnetization changes. This magnetization vibration is, for example, precession. Ferromagnetic resonance is a phenomenon in which magnetization is oscillated at a specific frequency and the amplitude of vibration of the magnetization is maximized by applying energy varying at a specific frequency. Hereinafter, the frequency of magnetization vibration when the amplitude of magnetization vibration becomes maximum is referred to as a ferromagnetic resonance frequency. Examples of energy that generates ferromagnetic resonance include a high-frequency magnetic field and a high-frequency current.

  Hereinafter, an element using spintronics is referred to as a spintronic element. As a typical spintronic device, a magnetization fixed layer whose magnetization direction is fixed, a magnetization free layer whose magnetization direction changes according to the direction of the external magnetic field, and a magnetization fixed layer and a magnetization free layer are arranged. A magnetoresistive element including a spacer layer is known.

  Patent Document 1 discloses a frequency conversion element including a magnetoresistive effect element, a mechanism for applying a magnetic field to the frequency conversion element, a local oscillator for applying a local oscillation signal to the frequency conversion element, a frequency conversion element, A frequency conversion device that is electrically connected and has an input terminal for inputting an external input signal is described.

International Publication No. 2010/119568

  As a band pass filter, an elastic wave filter configured using an elastic wave resonator is known. The acoustic wave resonator is a resonator configured using an acoustic wave element. An elastic wave element is an element using an elastic wave. There are surface acoustic wave elements that use surface acoustic waves and bulk acoustic wave elements that use bulk acoustic waves.

  The passband cannot be changed with a general bandpass filter, not limited to the acoustic wave filter.

  Since the magnetization free layer of the magnetoresistive effect element can cause ferromagnetic resonance, there is a possibility that a resonator using the magnetoresistive effect element and a high frequency filter using the resonator can be realized. As described in Patent Document 1, the ferromagnetic resonance frequency of the magnetization free layer can be changed by changing the magnitude of the external magnetic field applied to the magnetization free layer, for example. Therefore, there is a possibility that a bandpass filter that can change the pass band can be realized by using a magnetoresistive element.

  However, in order to realize a practical bandpass filter using a magnetoresistive effect element, how to widen the passband becomes a problem.

  The present invention has been made in view of such problems, and an object thereof is to provide a filter device using a magnetoresistive effect element, which can be operated as a practical band-pass filter. is there.

  The filter device of the present invention includes a magnetoresistive effect element, an input port to which a high frequency input signal is applied, an output port in which a high frequency output signal appears, and an energy applying unit. The magnetoresistive effect element includes a first magnetization free layer having a first magnetization and a second magnetization free layer having a second magnetization. The direction of the first magnetization changes according to the direction of the first effective magnetic field that acts on the first magnetization free layer. The direction of the second magnetization changes according to the direction of the second effective magnetic field acting on the second magnetization free layer. The energy applying unit applies energy to the magnetoresistive element for generating vibration based on the high-frequency input signal in the first magnetization and the second magnetization. The high-frequency output signal is caused by vibrations of the first magnetization and the second magnetization.

  In the filter device of the present invention, the ferromagnetic resonance frequencies of the first magnetization free layer and the second magnetization free layer may be different from each other.

  The filter device of the present invention may further include at least one external magnetic field application unit that applies an external magnetic field to at least one of the first magnetization free layer and the second magnetization free layer. The at least one external magnetic field application unit applies a first external magnetic field application unit that applies the first external magnetic field to the first magnetization free layer, and a second external magnetic field to the second magnetization free layer. A second external magnetic field application unit to be applied may be used. The first external magnetic field and the second external magnetic field may have different sizes.

  In the filter device of the present invention, the first magnetization free layer and the second magnetization free layer may have different magnitudes of magnetic anisotropy magnetic fields acting on them.

  In the filter device of the present invention, the energy applying unit may apply a high frequency magnetic field generated based on a high frequency input signal to the magnetoresistive effect element as the energy. Or an energy provision part may provide a high frequency input signal to a magnetoresistive effect element as the said energy.

  In the filter device of the present invention, the magnetoresistive element may further include a spacer layer disposed between the first magnetization free layer and the second magnetization free layer. In this case, the high frequency output signal may correspond to a change in the resistance value of the magnetoresistive effect element.

  In the filter device of the present invention, the magnetoresistive effect element further includes a magnetization fixed portion disposed between the first magnetization free layer and the second magnetization free layer, the first magnetization free layer, and the magnetization fixed. A first spacer layer disposed between the first and second magnetization layers, and a second spacer layer disposed between the second magnetization free layer and the magnetization fixed portion. The magnetization fixed part includes at least one magnetization fixed layer having magnetization whose direction is fixed. In this case, the high-frequency output signal is transmitted through the first fixed path, the first spacer layer, and the first magnetization free layer, and the fixed magnetization section, the second spacer layer, and the second magnetization free layer. It may correspond to a change in the resistance value of the parallel circuit composed of the second route passing through.

  According to the filter device of the present invention, a high frequency output signal having a frequency equal to the frequency of the high frequency input signal can be obtained, and a high frequency with respect to the power of the high frequency input signal can be obtained in a predetermined frequency band corresponding to the pass band of the band pass filter. The power ratio of the output signal can be increased. Therefore, the filter device of the present invention can be operated as a bandpass filter. According to the filter device of the present invention, the ferromagnetic resonance frequency of the first magnetization free layer and the ferromagnetic resonance frequency of the second magnetization free layer can be made different from each other. As a result, the filter device of the present invention can widen the passband when operated as a bandpass filter. For these reasons, according to the present invention, it is possible to realize a filter device that can be operated as a practical bandpass filter.

It is explanatory drawing which shows typically the filter apparatus which concerns on the 1st Embodiment of this invention. It is a perspective view which shows the magnetoresistive effect element in the 1st Embodiment of this invention, the 1st external magnetic field application part, and the 2nd external magnetic field application part. It is explanatory drawing which shows the direction of the 1st magnetization in the 1st Embodiment of this invention, and the direction of the 2nd magnetization. It is a characteristic view which shows typically the frequency characteristic of the input-output power ratio in the filter apparatus which concerns on the 1st Embodiment of this invention. It is a top view which shows 1 process in the manufacturing method of the filter apparatus which concerns on the 1st Embodiment of this invention. FIG. 6 is a plan view illustrating a process following FIG. 5. FIG. 7 is a plan view illustrating a process following the process in FIG. 6. FIG. 8 is a plan view illustrating a process following the process in FIG. 7. FIG. 9 is a plan view illustrating a process following the process in FIG. 8. FIG. 10 is a plan view illustrating a process following the process in FIG. 9. FIG. 11 is a plan view illustrating a process following FIG. 10. It is a side view which shows the principal part of the filter apparatus which concerns on the 1st Embodiment of this invention. It is a perspective view which shows the 1st example of the magnetoresistive effect element in the 2nd Embodiment of this invention. It is a perspective view which shows the 2nd example of the magnetoresistive effect element in the 2nd Embodiment of this invention. It is explanatory drawing which shows typically the filter apparatus which concerns on the 3rd Embodiment of this invention. It is explanatory drawing which shows typically the filter apparatus which concerns on the 4th Embodiment of this invention. It is a perspective view which shows the magnetoresistive effect element in the 4th Embodiment of this invention, the 1st external magnetic field application part, and the 2nd external magnetic field application part. It is explanatory drawing which shows the direction of the 1st thru | or 4th magnetization in the 4th Embodiment of this invention. It is explanatory drawing which shows typically the filter apparatus which concerns on the 5th Embodiment of this invention.

[First Embodiment]
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, the configuration of the filter device according to the first embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is an explanatory diagram schematically showing the filter device according to the present embodiment. FIG. 2 is a perspective view showing the magnetoresistive effect element, the first external magnetic field application unit, and the second external magnetic field application unit in the present embodiment. As shown in FIG. 1, the filter device 1 according to the present embodiment includes a magnetoresistive effect element 2, an input port 3 to which a high frequency input signal is applied, an output port 4 at which a high frequency output signal appears, and energy application. Part 5.

  As shown in FIGS. 1 and 2, the magnetoresistive element 2 includes a first magnetization free layer 21 having a first magnetization, a second magnetization free layer 23 having a second magnetization, And a spacer layer 22 arranged between the second magnetization free layer 23 and the second magnetization free layer 23. In addition, the magnetoresistive effect element 2 has a first end face 2 a and a second end face 2 b located at both ends in the stacking direction of a plurality of layers constituting the magnetoresistive effect element 2. The second magnetization free layer 23, the spacer layer 22, and the first magnetization free layer 21 are stacked in this order from the second end face 2b side. FIG. 2 shows an example in which the magnetoresistive element 2 has a cylindrical shape. However, the shape of the magnetoresistive effect element 2 may be other shapes such as a rectangular parallelepiped shape.

  In the magnetoresistive effect element 2, the magnetoresistive effect is manifested by the interaction between the first magnetization and the second magnetization. More specifically, as the relative angle between the first magnetization direction and the second magnetization direction approaches 0 ° to 180 °, the resistance value of the magnetoresistive element 2 increases.

  The energy applying unit 5 applies energy for causing the first magnetization and the second magnetization to vibrate based on a high frequency input signal to the magnetoresistive element 2. In the present embodiment, a high frequency magnetic field generated based on a high frequency input signal is used as the energy. The energy applying unit 5 is configured to apply a high frequency magnetic field to the magnetoresistive element 2 as energy. More specifically, the energy applying unit 5 includes line portions 51, 52, 53, 54, and 55 that transmit a high frequency input signal applied to the input port 3. The line portions 51, 52, 53, 54, and 55 are connected in series in this order from the input port 3 side. The line portion 52 and the line portion 54 are disposed on both sides of the magnetoresistive effect element 2 in a direction parallel to both surfaces of the spacer layer 22. The line portions 52 and 54 generate a high frequency magnetic field based on the high frequency input signal. This high frequency magnetic field is applied to the magnetoresistive element 2.

  The filter device 1 further includes at least one external magnetic field application unit that applies an external magnetic field to at least one of the first magnetization free layer 21 and the second magnetization free layer 23. Particularly in the present embodiment, at least one external magnetic field application unit includes a first external magnetic field application unit 6 that applies a first external magnetic field to the first magnetization free layer 21, and a second magnetization free layer. 23 is a second external magnetic field application unit 7 that applies a second external magnetic field to 23. As shown in FIG. 2, the first external magnetic field application unit 6 includes a conducting wire 61 disposed in the vicinity of the first magnetization free layer 21. The second external magnetic field application unit 7 includes a conducting wire 71 disposed in the vicinity of the second magnetization free layer 23. The conducting wires 61 and 71 generate a magnetic field around them when energized. A part of the magnetic field generated by the conducting wire 61 becomes the first external magnetic field, and a part of the magnetic field generated by the conducting wire 71 becomes the second external magnetic field.

  The first external magnetic field application unit 6 can change the magnitude of the first external magnetic field by changing the magnitude of the current flowing through the conducting wire 61. Similarly, the second external magnetic field application unit 7 can change the magnitude of the second external magnetic field by changing the magnitude of the current flowing through the conducting wire 71. The range of the magnitude of the first and second external magnetic fields that can be changed by the first and second external magnetic field application units 6 and 7 is, for example, 0 to 1 kOe (1Oe is 79.6 A / m).

  A magnetic field in which a high frequency magnetic field and a first external magnetic field are combined is applied to the first magnetization free layer 21. A magnetic field obtained by synthesizing a high-frequency magnetic field and a second external magnetic field is applied to the second magnetization free layer 23. Hereinafter, a magnetic field in which the high-frequency magnetic field and the first external magnetic field are combined is referred to as a first high-frequency superimposed magnetic field, and a magnetic field in which the high-frequency magnetic field and the second external magnetic field are combined is referred to as a second high-frequency superimposed magnetic field.

  The direction of the first magnetization of the first magnetization free layer 21 changes according to the direction of the first effective magnetic field acting on the first magnetization free layer 21. The first effective magnetic field is a combination of all types of magnetic fields that act on the first magnetization. The magnetic field acting on the first magnetization includes a magnetic anisotropy magnetic field, an exchange magnetic field, a demagnetizing field, and the like in addition to the first high-frequency superimposed magnetic field. In the present embodiment, the direction of the first effective magnetic field matches or substantially matches the direction of the first high-frequency superimposed magnetic field.

  As will be described in detail later, the high-frequency magnetic field changes the direction of the first high-frequency superimposed magnetic field to vibrate around the direction of the first external magnetic field. The frequency of change in the direction of the first high-frequency superimposed magnetic field is equal to the frequency of the high-frequency input signal. The first magnetization vibrates at the frequency of the high frequency input signal.

  Similarly, the direction of the second magnetization of the second magnetization free layer 23 changes according to the direction of the second effective magnetic field acting on the second magnetization free layer 23. The second effective magnetic field is a combination of all types of magnetic fields that act on the second magnetization. The magnetic field acting on the second magnetization includes a magnetic anisotropic magnetic field, an exchange magnetic field, a demagnetizing field, and the like in addition to the second high-frequency superimposed magnetic field. In the present embodiment, the direction of the second effective magnetic field matches or substantially matches the direction of the second high-frequency superimposed magnetic field.

  As will be described in detail later, the high-frequency magnetic field changes the direction of the second high-frequency superimposed magnetic field to vibrate around the direction of the second external magnetic field. The frequency of change in the direction of the second high frequency superimposed magnetic field is equal to the frequency of the high frequency input signal. The second magnetization vibrates at the frequency of the high frequency input signal.

  The high-frequency output signal is caused by vibrations of the first magnetization and the second magnetization. Particularly in the present embodiment, the high-frequency output signal corresponds to a change in the resistance value of the magnetoresistive element 2. That is, when the first magnetization and the second magnetization vibrate, the relative angle between the first magnetization direction and the second magnetization direction changes, and as a result, the resistance value of the magnetoresistive element 2 changes. A high frequency output signal is generated by a change in the resistance value of the magnetoresistive element 2.

  The filter device 1 further includes an output signal line 8. The output signal line 8 transmits the high frequency output signal generated in the magnetoresistive effect element 2 to the output port 4. As a result, a high frequency output signal appears at the output port 4.

  The filter device 1 further includes a first electrode 11, a second electrode 12, and a ground electrode 13. The first electrode 11 and the second electrode 12 are provided such that the magnetoresistive element 2 is interposed therebetween. The first electrode 11 and the second electrode 12 are used for passing a direct current described later through the magnetoresistive element 2. The first electrode 11 is in contact with the first end face 2 a of the magnetoresistive effect element 2. The second electrode 12 is in contact with the second end face 2 b of the magnetoresistive effect element 2. The direct current flows in a direction intersecting the surface of each layer constituting the magnetoresistive effect element 2, for example, in a direction perpendicular to the surface of each layer constituting the magnetoresistive effect element 2.

  In the example shown in FIG. 1, the input port 3 has a pair of terminals 31 and 32. The end of the line portion 51 opposite to the connection point between the line portions 51 and 52 is electrically connected to the terminal 31.

  In the example shown in FIG. 1, the output port 4 has a pair of terminals 41 and 42. One end of the output signal line 8 is electrically connected to the terminal 41. The other end of the output signal line 8 is electrically connected to the first electrode 11. The high frequency output signal appears as a change in the potential of the terminal 41.

  The end of the line portion 55 opposite to the connection point of the line portions 54 and 55, the terminal 32 of the input port 3, and the terminal 42 of the output port 4 are electrically connected to the ground electrode 13. The potential of the ground electrode 13 is used as a reference potential.

  The first and second electrodes 11 and 12 may be composed of a single layer film made of any one of Al, Ta, Cu, Au, AuCu, and Ru, for example. You may be comprised by the laminated body of the some film | membrane which consists of either of them.

  The filter device 1 further includes a choke coil 14, a DC current line 15, and a DC current input terminal 16. One end of the choke coil 14 is electrically connected to the output signal line 8. The other end of the choke coil 14 is electrically connected to the ground electrode 13. One end of the DC current line 15 is electrically connected to the second electrode 12. The other end of the DC current line 15 is electrically connected to the DC current input terminal 16. In terms of circuit configuration, the magnetoresistive effect element 2 is located between the DC current input terminal 16 and the choke coil 14. A direct current is input to the direct current input terminal 16, and this direct current is supplied to the magnetoresistive effect element 2. The output signal line 8, the DC current line 15, and the ground electrode 13 may be configured by a microstrip line or a coplanar waveguide.

  The choke coil 14 has an inductance. Thereby, the impedance of the choke coil 14 increases as the frequency of the current passing through the choke coil 14 increases. Therefore, the choke coil 14 allows a direct current passing through the output signal line 8 to pass through the ground electrode 13 and exhibits a high impedance for a high-frequency output signal passing through the output signal line 8.

  As the choke coil 14, for example, a chip inductor or a line is used. The inductance of the choke coil 14 is preferably 10 nH or more. Note that the filter device 1 may include a resistance element having an inductance component instead of the choke coil 14.

  When the filter device 1 is operated, a direct current source 17 is provided between the direct current input terminal 16 and the ground electrode 13 as shown in FIG. Thereby, a closed circuit including the direct current source 17, the direct current input terminal 16, the direct current line 15, the magnetoresistive effect element 2, the output signal line 8, the choke coil 14, and the ground electrode 13 is formed. The direct current source 17 generates a direct current flowing through this closed circuit. In the magnetoresistive effect element 2, a direct current flows in the direction from the second magnetization free layer 23 toward the first magnetization free layer 21.

  The direct current source 17 is configured by, for example, a circuit that combines a direct current voltage source and a resistor. A variable resistor or a fixed resistor is used as the resistor. When a variable resistor is used, the magnitude of the direct current can be changed. When a fixed resistor is used, the direct current becomes a constant value.

  Here, the material of each layer which comprises the magnetoresistive effect element 2 is demonstrated. The first and second magnetization free layers 21 and 23 of the magnetoresistive effect element 2 are made of a ferromagnetic material. The first and second magnetization free layers 21 and 23 can be constituted by, for example, films made of CoFe, CoFeB, CoFeSi, CoMnGe, CoMnSi, CoMnAl, or Heusler alloy. The thickness of this film is preferably in the range of 1 to 10 nm.

The spacer layer 22 of the magnetoresistive effect element 2 may be entirely made of a nonmagnetic material. The nonmagnetic material constituting the spacer layer 22 may be a conductive material, an insulating material, or a semiconductor material. Examples of the nonmagnetic conductive material constituting the spacer layer 22 include Cu, Ag, Au, and Ru. Examples of the nonmagnetic insulating material constituting the spacer layer 22 include Al ₂ O ₃ and MgO. When the entire spacer layer 22 is made of a nonmagnetic conductive material or insulating material, the thickness of the spacer layer 22 is preferably in the range of 0.5 to 3.0 nm.

  Examples of the nonmagnetic semiconductor material that forms the spacer layer 22 include an oxide semiconductor containing one or more of Zn, In, Sn, and Ga. When the entire spacer layer 22 is made of a nonmagnetic semiconductor material, the thickness of the spacer layer 22 is preferably in the range of 1.0 to 4.0 nm.

The spacer layer 22 may include an insulating portion made of an insulating material and one or more energization portions made of a conductive material and provided in the insulating portion. Examples of the insulating material constituting the insulating portion include Al ₂ O ₃ and MgO. Examples of the conductive material constituting the energizing portion include CoFe, CoFeB, CoFeSi, CoMnGe, CoMnSi, CoMnAl, Fe, Co, Au, Cu, Al, and Mg. In this case, the thickness of the spacer layer 22 is preferably in the range of 0.5 to 2.0 nm.

  Next, the first magnetization direction of the first magnetization free layer 21 and the second magnetization direction of the second magnetization free layer 23 will be described with reference to FIGS. 2 and 3. In the following description, the direction of the first magnetization is represented by the symbol D1, and the direction of the second magnetization is represented by the symbol D2. FIG. 3 shows a first magnetization direction D1 and a second magnetization direction D2.

  Here, as shown in FIG. 2, an X direction, a Y direction, and a Z direction are defined. The X direction, the Y direction, and the Z direction are orthogonal to each other. In the present embodiment, one direction perpendicular to both surfaces of the spacer layer 22 (the direction toward the upper side in FIG. 2) is defined as the Z direction. Both the X direction and the Y direction are parallel to both surfaces of the spacer layer 22. FIG. 3 also shows the X, Y, and Z directions shown in FIG.

  As shown in FIG. 2, the first magnetization free layer 21 and the conducting wire 61 of the first external magnetic field application unit 6 are arranged in this order in the Z direction. The conducting wire 61 extends in the X direction. When operating the filter device 1, the power source V <b> 1 is connected to the conducting wire 61 so that a current flows in the X direction in the conducting wire 61. In this case, the direction of the first external magnetic field is the Y direction. FIG. 3 shows a state in which the direction D1 of the first magnetization coincides with the direction of the first external magnetic field (Y direction).

  Further, as shown in FIG. 2, the conducting wire 71 and the second magnetization free layer 23 of the second external magnetic field application unit 7 are arranged in this order in the Z direction. The conducting wire 71 extends in the Y direction. When operating the filter device 1, the power supply V <b> 2 is connected to the conducting wire 71 so that a current flows in the Y direction in the conducting wire 71. In this case, the direction of the second external magnetic field is the X direction. Therefore, the direction of the second external magnetic field is orthogonal to the direction of the first external magnetic field. FIG. 3 shows a state in which the second magnetization direction D2 matches the second external magnetic field direction (X direction).

  Next, the operation and effect of the filter device 1 according to the present embodiment will be described. First, the behavior of the first magnetization of the first magnetization free layer 21 and the second magnetization of the second magnetization free layer 23 will be described. In general, the behavior of magnetization of a ferromagnetic material to which a magnetic field acts is expressed using an LLG (Landau Lifshitz Gilbert) equation. The LLG equation considering the spin transfer torque represents the precession torque, the damping torque and the spin transfer torque that act on the magnetization. A first effective magnetic field acts on the first magnetization, and a second effective magnetic field acts on the second magnetization. Therefore, precession torque and damping torque act on each of the first and second magnetizations. In the present embodiment, a direct current is passed through the magnetoresistive element 2. Thereby, spin transfer torque further acts on each of the first and second magnetizations. Spin transfer torque refers to the magnetization of a ferromagnet so that the magnetization of the ferromagnet rotates in the direction opposite to the change of the spin angular momentum in the change of the spin current in the ferromagnet in which the inflow or outflow of the spin current occurs. Is the torque acting on the.

  In the present embodiment, the energy applying unit 5 applies energy to the magnetoresistive element 2 to cause the first and second magnetizations to vibrate based on the high-frequency input signal. In the present embodiment, the energy is a high frequency magnetic field. In the present embodiment, the angle formed by the direction of the high frequency magnetic field with respect to the direction of the first external magnetic field is equal to the angle formed by the direction of the high frequency magnetic field with respect to the direction of the second external magnetic field. That is, both of these angles are 45 ° or 135 °.

  When a high frequency magnetic field is applied to the magnetoresistive effect element 2, the directions of the first and second effective magnetic fields change with the frequency of the high frequency input signal. As a result, the respective damping torques acting on the first and second magnetizations change. As a result, the first and second magnetizations vibrate at the frequency of the high-frequency input signal so that their directions change. As a result, the relative angle between the direction of the first magnetization and the direction of the second magnetization changes, and the resistance value of the magnetoresistive effect element 2 changes. As a result, a high frequency output signal having a frequency equal to the frequency of the high frequency input signal is generated.

  According to the filter device 1 according to the present embodiment, a high frequency output signal having a frequency equal to the frequency of the high frequency input signal can be obtained as described above. Further, according to the filter device 1, as described below, the ratio of the power of the high-frequency output signal to the power of the high-frequency input signal can be increased in a predetermined frequency band corresponding to the pass band of the band-pass filter. it can. Therefore, the filter device 1 can be operated as a band pass filter.

  In the filter device 1 according to the present embodiment, the ferromagnetic resonance frequency of the first magnetization free layer 21 and the ferromagnetic resonance frequency of the second magnetization free layer 23 can be made different from each other. This will be described in detail below. The first magnetization free layer 21 has a first ferromagnetic resonance frequency f1, and the second magnetization free layer 23 has a second ferromagnetic resonance frequency f2. The first and second ferromagnetic resonance frequencies f1 and f2 vary depending on the magnitudes of the first and second effective magnetic fields, respectively. According to the present embodiment, the magnitudes of the first and second effective magnetic fields are made different from each other by making the magnitudes of the first and second external magnetic fields different from each other. Can be made different from each other.

  When the frequency of the high frequency input signal is equal to the first ferromagnetic resonance frequency f1, ferromagnetic resonance occurs in the first magnetization free layer 21, and the amplitude of vibration of the first magnetization is maximized. When the frequency of the high-frequency input signal is equal to the second ferromagnetic resonance frequency f2, ferromagnetic resonance occurs in the second magnetization free layer 23, and the amplitude of vibration of the second magnetization is maximized.

  Here, the ratio of the power of the high frequency output signal to the power of the high frequency input signal is referred to as the input / output power ratio. FIG. 4 is a characteristic diagram schematically showing the frequency characteristic of the input / output power ratio in the filter device 1. In FIG. 4, the horizontal axis indicates the frequency, and the vertical axis indicates the input / output power ratio. As shown in FIG. 4, the frequency characteristics of the input / output power ratio have maximum values at the first ferromagnetic resonance frequency f1 and the second ferromagnetic resonance frequency f2, respectively.

  In the frequency characteristic of the input / output power ratio shown in FIG. 4, the frequency band in which the input / output power ratio is equal to or higher than a predetermined value corresponds to the pass band of the bandpass filter. The predetermined value is, for example, 1/2 of the maximum value of the input / output power ratio. According to the filter device 1 according to the present embodiment, as shown in FIG. 4, when the frequency characteristic of the input / output power ratio takes the maximum value at the two frequencies f1 and f2, the frequency characteristic of the input / output power ratio is obtained. As compared with the case where takes a maximum value at only one frequency, the predetermined frequency band corresponding to the pass band of the band-pass filter can be widened. Thus, in the filter device 1 according to the present embodiment, the first and second ferromagnetic resonance frequencies f1 and f2 are made different from each other, thereby widening the passband when operated as a bandpass filter. Can do.

  From the above, according to the present embodiment, it is possible to realize the filter device 1 that can be operated as a practical bandpass filter.

  In addition, according to the present embodiment, the first and second ferromagnetic resonance frequencies f1 and f2 can be changed by changing the magnitudes of the first and second external magnetic fields. Thereby, according to the filter apparatus 1 which concerns on this Embodiment, the pass band when it is made to operate | move as a band pass filter can be changed.

  Further, the magnetoresistive effect element 2 in the present embodiment does not include a magnetization fixed layer. Therefore, according to the filter device 1 according to the present embodiment, the function does not deteriorate due to the change in the magnetization direction of the magnetization fixed layer due to factors such as heat.

  Next, with reference to FIG. 5 thru | or FIG. 11, the manufacturing method of the filter apparatus 1 which concerns on this Embodiment is demonstrated. 5 to 11 show a part of the upper surface of the laminated body in the manufacturing process of the filter device 1. In the manufacturing method of the filter device 1, first, a first insulating layer (not shown) and a line portion 53 are sequentially formed on a substrate (not shown). FIG. 5 shows the stacked body after the line portion 53 is formed.

  FIG. 6 shows the next step. In this step, first, the insulating layer 91 is formed so as to cover the line portion 53 and the first insulating layer. Next, the conducting wire 71 of the second external magnetic field application unit 7 is formed on the insulating layer 91.

  FIG. 7 shows the next step. In this step, first, a second insulating layer (not shown) is formed so as to cover the conductive wire 71 and the insulating layer 91. Next, the second electrode 12 is formed on the second insulating layer. In addition, the 2nd electrode 12 is not formed in the area | region where the 3rd, 4th, 7th, and 8th hole which will be mentioned later is formed, and its vicinity.

  FIG. 8 shows the next step. In this step, first, the magnetoresistive element 2 is formed on the second electrode 12. The magnetoresistive effect element 2 is formed, for example, by forming a laminated film to be the magnetoresistive effect element 2 by patterning later and then patterning the laminated film. Next, an insulating layer 92 is formed around the magnetoresistive effect element 2.

  FIG. 9 shows the next step. In this step, the first electrode 11 is formed on the magnetoresistive effect element 2 and the insulating layer 92. Note that the first electrode 11 is not formed in a region where second to fourth, seventh, and eighth holes, which will be described later, are to be formed and in the vicinity thereof.

  FIG. 10 shows the next step. In this step, first, the insulating layer 93 is formed on the first electrode 11 and the insulating layer 92. Next, the conducting wire 61 of the first external magnetic field application unit 6 is formed on the insulating layer 93.

  FIG. 11 shows the next step. In this step, first, an insulating layer 94 is formed so as to cover the conducting wire 61 and the insulating layer 93. Next, first to eighth holes 8H, 15H, 52H, 53H, 62H, 63H, 72H and 73H are formed. The first hole 8H penetrates the insulating layers 93 and 94 and exposes the first electrode 11. The second hole 15H penetrates the insulating layers 92 to 94 and exposes the second electrode 12. The third and fourth holes 52H and 53H penetrate the insulating layers 91 to 94 and the second insulating layer in the vicinity of the magnetoresistive element 2, and expose the line portion 53. The fifth and sixth holes 62H and 63H penetrate the insulating layer 94 and expose the vicinity of both ends of the conducting wire 61 in the longitudinal direction. The seventh and eighth holes 72H and 73H penetrate the insulating layers 92 to 94 and the second insulating layer, and expose the vicinity of both ends in the longitudinal direction of the conducting wire 71.

  Next, a part of the output signal line 8 is formed in the first hole 8H so as to be connected to the first electrode 11. Further, a part of the DC current line 15 is formed in the second hole 15H so as to be connected to the second electrode 12. Further, the line portions 52 and 54 are formed in the third and fourth holes 52H and 54H so as to be connected to the line portion 53, respectively. Further, columnar conductor portions 62 and 63 are formed in the fifth and sixth holes 62H and 63H so as to be connected to the conducting wire 61, respectively. Further, columnar conductor portions 72 and 73 are formed in the seventh and eighth holes 72H and 73H so as to be connected to the conducting wire 71, respectively. The power source V1 shown in FIG. 2 is connected to the conducting wire 61 via the columnar conductor portions 62 and 63. The power source V <b> 2 shown in FIG. 2 is connected to the conductive wire 71 through the columnar conductor portions 72 and 73.

  The main part 1M of the filter device 1 is completed by a series of steps from the step shown in FIG. 5 to the step shown in FIG. FIG. 12 is a side view showing the main part 1M of the filter device 1. FIG. In FIG. 12, the insulating layers 91 to 94, the first insulating layer, the second insulating layer, and the substrate are omitted. The remaining part of the filter device 1 is connected to the main part 1M of the filter device 1 shown in FIG.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. In the present embodiment, the configuration and shape of the magnetoresistive effect element 2 are different from those of the first embodiment. Hereinafter, with reference to FIG. 13 and FIG. 14, the 1st and 2nd example of the magnetoresistive effect element 2 in this Embodiment is demonstrated.

  FIG. 13 shows a first example of the magnetoresistive effect element 2. FIG. 14 shows a second example of the magnetoresistive effect element 2. As shown in FIGS. 13 and 14, the magnetoresistive effect element 2 includes the first metal layer 24 and the second magnetic layer 24 in addition to the first magnetization free layer 21, the second magnetization free layer 23, and the spacer layer 22. The metal layer 25 is included. The first metal layer 24 is provided between the first magnetization free layer 21 and the first electrode 11 (see FIG. 1). The second metal layer 25 is provided between the second magnetization free layer 23 and the second electrode 12 (see FIG. 1). The first metal layer 24 is used as a cap layer. The second metal layer 25 is used as a seed layer or a buffer layer. The 1st and 2nd metal layers 24 and 25 are comprised by the single layer film or multilayer film containing one or more of Ru, Ta, Cu, and Cr, for example. The thicknesses of the first and second metal layers 24 and 25 are preferably in the range of 2 to 10 nm.

  As shown in FIGS. 13 and 14, the shape of the first and second end faces 2 a and 2 b of the magnetoresistive effect element 2 is rectangular. Particularly in the present embodiment, the shape of the first end surface 2a is a rectangle, and the shape of the second end surface 2b is a square or a rectangle.

  In addition to the first and second end faces 2a and 2b, the magnetoresistive effect element 2 has two side faces 2c and 2d located on opposite sides in the Y direction. The side surfaces 2c and 2d are perpendicular to the Y direction. As shown in FIG. 13, in the first example, the shape of the side surfaces 2c and 2d is a trapezoid. As shown in FIG. 14, in the second example, the shape of the side surfaces 2c and 2d is a shape in which two trapezoids are stacked.

  In the present embodiment, the shape of the lower surface of the first magnetization free layer 21 is a rectangle, and the shape of the lower surface of the second magnetization free layer 23 is a square or a rectangle. Hereinafter, the X-direction dimension and the Y-direction dimension of the lower surface of the first magnetization free layer 21 are represented by symbols Xa and Ya, respectively. Represented by symbols Xb and Yb, respectively. Xa is smaller than Xb. Ya and Yb are equal to each other.

  The ratio Yb / Xb is 1 or a value close to 1. The ratio Ya / Xa is greater than 1 and greater than the ratio Yb / Xb. Therefore, the magnetic anisotropy magnetic field (hereinafter referred to as the first magnetic anisotropy magnetic field) acting on the first magnetization free layer 21 by the shape magnetic anisotropy of the first magnetization free layer 21 is the second. The magnetic anisotropy magnetic field acting on the second magnetization free layer 23 due to the shape magnetic anisotropy of the magnetization free layer 23 (hereinafter referred to as the second magnetic anisotropy magnetic field) is larger. The direction of the first magnetic anisotropic magnetic field is a direction parallel to the Y direction.

  As shown in FIGS. 13 and 14, the ratio Ya / Xa in the second example is larger than the ratio Ya / Xa in the first example. Therefore, the first magnetic anisotropy field in the second example is larger than the first magnetic anisotropy field in the first example.

  In the present embodiment, the magnitudes of the first magnetic anisotropic magnetic field and the second magnetic anisotropic magnetic field are different from each other. In the present embodiment, by utilizing this, the magnitudes of the first effective magnetic field acting on the first magnetization free layer 21 and the second effective magnetic field acting on the second magnetization free layer 23 are made different from each other. It is possible.

  In the present embodiment, the magnitudes of the first and second external magnetic fields may be different from each other or may be the same as in the first embodiment. In the present embodiment, since the magnitudes of the first and second magnetic anisotropic magnetic fields are different from each other even when the magnitudes of the first and second external magnetic fields are equal, the first and second effective magnetic fields are different. Can be made different in size. When the first external magnetic field is not applied to the first magnetization free layer 21, the direction of the first magnetic anisotropic magnetic field is the Y direction or the direction opposite to the Y direction. As in the first embodiment, when the direction of the first external magnetic field is the Y direction, the direction of the first magnetic anisotropy magnetic field is the Y direction.

  In addition, the filter device 1 according to the present embodiment may not include the first external magnetic field application unit 6 (see FIG. 1) in the first embodiment. In this case, the first external magnetic field in the first embodiment is not applied to the first magnetization free layer 21. In this case, the first effective magnetic field is mainly a combination of the first magnetic anisotropic magnetic field and the high-frequency magnetic field generated by the energy applying unit 5 (see FIG. 1). Also in this case, the magnitudes of the first and second effective magnetic fields can be made different from each other. In addition, by setting the direction of the second external magnetic field to be different from the direction of the first magnetic anisotropy magnetic field, the directions of the first and second effective magnetic fields can be made different from each other.

  In the case where the first external magnetic field is not applied to the first magnetization free layer 21, the first magnetization direction D1 in a state where no high-frequency magnetic field is applied to the first magnetization free layer 21 is set in advance. It is preferable to set in the Y direction or the direction opposite to the Y direction. For example, when the direction D1 of the first magnetization is set in the Y direction in advance, the direction of the first magnetic anisotropic magnetic field is the Y direction.

  13 and 14 show examples in which the direction of the first magnetic anisotropic magnetic field is the Y direction. Further, in FIGS. 13 and 14, the direction D1 of the first magnetization coincides with the direction of the first magnetic anisotropic magnetic field (Y direction), and the second magnetization of the second magnetization free layer 23 has the second magnetization. The direction D2 shows a state in which the direction of the second external magnetic field (X direction) coincides.

  In the present embodiment, as a method of making the magnitudes of the first and second magnetic anisotropic magnetic fields different from each other, the shape magnetic anisotropy of the first and second magnetization free layers 21 and 23 is different. In addition to or instead of making the first and second magnetization free layers 21 and 23 different in composition, the magnetocrystalline anisotropy of the first and second magnetization free layers 21 and 23 is made different. You may use the method.

  Other configurations, operations, and effects in the present embodiment are the same as those in the first embodiment.

[Third Embodiment]
Next, a third embodiment of the present invention will be described. First, the configuration of the filter device 1 according to the present embodiment will be described with reference to FIG. The configuration of the filter device 1 according to the present embodiment is different from that of the first embodiment in the following points. The filter device 1 according to the present embodiment includes an energy applying unit 105 instead of the energy applying unit 5 in the first embodiment. Further, in the present embodiment, the DC current line 15 in the first embodiment is not provided.

  The energy applying unit 105 applies a high frequency input signal to the magnetoresistive effect element 2 as energy for generating vibration based on the high frequency input signal in the first magnetization and the second magnetization. The energy applying unit 105 includes an input signal line 151.

  The input signal line 151 transmits a high frequency input signal applied to the input port 3 to the magnetoresistive element 2. In the present embodiment, one end of the input signal line 151 is electrically connected to the terminal 31 of the input port 3. The other end of the input signal line 151 is electrically connected to the second electrode 12. The input signal line 151 and the ground electrode 13 may be configured by a microstrip line or a coplanar waveguide.

  In the present embodiment, the direct current input terminal 16 is electrically connected to the input signal line 151. When the filter device 1 is operated, a direct current source 17 is provided between the direct current input terminal 16 and the ground electrode 13 as shown in FIG. Thereby, a closed circuit including the direct current source 17, the direct current input terminal 16, the input signal line 151, the magnetoresistive effect element 2, the output signal line 8, the choke coil 14 and the ground electrode 13 is formed. The direct current source 17 generates a direct current flowing through this closed circuit.

  In the present embodiment, the high frequency magnetic field described in the first embodiment is not applied to the first magnetization free layer 21 of the magnetoresistive element 2. As described in the first embodiment, the direction of the first magnetization of the first magnetization free layer 21 changes according to the direction of the first effective magnetic field acting on the first magnetization free layer 21. . In the present embodiment, the direction of the first effective magnetic field coincides with or substantially coincides with the direction of the first external magnetic field applied to the first magnetization free layer 21 by the first external magnetic field application unit 6. .

  In the present embodiment, the high-frequency magnetic field described in the first embodiment is not applied to the second magnetization free layer 23 of the magnetoresistive element 2. As described in the first embodiment, the direction of the second magnetization of the second magnetization free layer 23 changes according to the direction of the second effective magnetic field acting on the second magnetization free layer 23. . In the present embodiment, the direction of the second effective magnetic field matches or substantially matches the direction of the second external magnetic field applied to the second magnetization free layer 23 by the second external magnetic field application unit 7. .

  Next, the operation and effect of the filter device 1 according to the present embodiment will be described. In the present embodiment, the energy applying unit 105 applies energy for causing the first and second magnetizations to vibrate based on the high-frequency input signal. In the present embodiment, the energy is a high frequency input signal. The high frequency input signal is superimposed on the direct current flowing through the magnetoresistive effect element 2 and applied to the magnetoresistive effect element 2. When a high-frequency input signal is applied to the magnetoresistive effect element 2, the current density in the first magnetization free layer 21 and the current density in the second magnetization free layer 23 change with the frequency of the high-frequency input signal. The respective spin transfer torques acting on the first and second magnetizations vary with the frequency of the high frequency input signal. As a result, the first and second magnetizations vibrate at the frequency of the high-frequency input signal so that their directions change. As a result, the relative angle between the direction of the first magnetization and the direction of the second magnetization changes, and the resistance value of the magnetoresistive effect element 2 changes. As a result, a high frequency output signal having a frequency equal to the frequency of the high frequency input signal is generated.

  In the present embodiment, similarly to the first embodiment, the first and second ferromagnetic resonance frequencies f1 and f2 can be changed by changing the magnitudes of the first and second external magnetic fields. . When the frequency of the high frequency input signal is equal to the first ferromagnetic resonance frequency f1, ferromagnetic resonance occurs in the first magnetization free layer 21, and the amplitude of vibration of the first magnetization is maximized. When the frequency of the high-frequency input signal is equal to the second ferromagnetic resonance frequency f2, ferromagnetic resonance occurs in the second magnetization free layer 23, and the amplitude of vibration of the second magnetization is maximized.

  Other configurations, operations, and effects in the present embodiment are the same as those in the first embodiment.

[Fourth Embodiment]
Next, a fourth embodiment of the present invention will be described. First, the configuration of the filter device 1 according to the present embodiment will be described with reference to FIGS. 16 and 17. FIG. 16 is an explanatory diagram schematically showing the filter device 1. FIG. 17 is a perspective view showing the magnetoresistive effect element, the first external magnetic field application unit, and the second external magnetic field application unit in the present embodiment.

  The configuration of the filter device 1 according to the present embodiment is different from that of the first embodiment in the following points. The filter device 1 according to the present embodiment includes a magnetoresistive effect element 102 instead of the magnetoresistive effect element 2 in the first embodiment. As shown in FIGS. 16 and 17, the magnetoresistive element 102 includes a first magnetization free layer 121 having a first magnetization, a second magnetization free layer 125 having a second magnetization, A magnetization pinned portion 123 arranged between the first magnetization free layer 121 and the second magnetization free layer 125, and a first spacer layer 122 arranged between the first magnetization free layer 121 and the magnetization pinned portion 123, And the second spacer layer 124 disposed between the second magnetization free layer 125 and the magnetization fixed portion 123.

  The magnetization fixed part 123 includes at least one magnetization fixed layer having magnetization whose direction is fixed. In the present embodiment, the magnetization fixed portion 123 includes a first magnetization fixed layer 123A having a third magnetization whose direction is fixed, and a second magnetization fixed layer 123C having a fourth magnetization whose direction is fixed. And an antiferromagnetic layer 123B. The first magnetization fixed layer 123A is disposed between the first spacer layer 122 and the antiferromagnetic layer 123B. The second magnetization fixed layer 123C is disposed between the second spacer layer 124 and the antiferromagnetic layer 123B. The antiferromagnetic layer 123B fixes the direction of the third magnetization of the first magnetization fixed layer 123A by exchange coupling with the first magnetization fixed layer 123A, and changes the first magnetization fixed layer 123C by exchange coupling with the first magnetization fixed layer 123A. The direction of the fourth magnetization of the second magnetization fixed layer 123C is fixed.

  In addition, the magnetoresistive effect element 102 has a first end face 102 a and a second end face 102 b located at both ends in the stacking direction of a plurality of layers constituting the magnetoresistive effect element 102. Second magnetization free layer 125, second spacer layer 124, second magnetization fixed layer 123C, antiferromagnetic layer 123B, first magnetization fixed layer 123A, first spacer layer 122, and first magnetization free layer 121 are laminated in this order from the second end face 102b side.

  The magnetoresistive effect element 102 includes a first path passing through the magnetization fixed portion 123, the first spacer layer 122, and the first magnetization free layer 121, the magnetization fixed portion 123, the second spacer layer 124, and the second A parallel circuit including a second path passing through the magnetization free layer 125 is configured. In the magnetoresistive effect element 102, the first magnetization of the first magnetization free layer 121 and the third magnetization of the first magnetization fixed layer 123A interact, and the direction of the first magnetization is the third magnetization. As the angle formed with respect to the direction approaches 0 ° to 180 °, the resistance value of the first path increases. In the magnetoresistive effect element 102, the second magnetization of the second magnetization free layer 125 and the fourth magnetization of the second magnetization fixed layer 123C interact, and the direction of the second magnetization is the fourth. As the angle formed with respect to the magnetization direction approaches from 0 ° to 180 °, the resistance value of the second path increases.

  In this Embodiment, the energy provision part 5 is comprised so that a high frequency magnetic field can be provided to the magnetoresistive effect element 102 as energy. The specific configuration and arrangement of the energy application unit 5 are the same as those in the first embodiment.

  In the present embodiment, the first external magnetic field application unit 6 applies the first external magnetic field to the first magnetization free layer 121. As shown in FIG. 17, the conducting wire 61 of the first external magnetic field application unit 6 is disposed in the vicinity of the first magnetization free layer 121. The second external magnetic field application unit 7 applies a second external magnetic field to the second magnetization free layer 125. As shown in FIG. 17, the conducting wire 71 of the second external magnetic field application unit 7 is disposed in the vicinity of the second magnetization free layer 125.

  A magnetic field obtained by combining a high-frequency magnetic field and a first external magnetic field, that is, a first high-frequency superimposed magnetic field is applied to the first magnetization free layer 121. The direction of the first magnetization of the first magnetization free layer 121 changes according to the direction of the first effective magnetic field acting on the first magnetization free layer 121. In the present embodiment, the direction of the first effective magnetic field matches or substantially matches the direction of the first high-frequency superimposed magnetic field.

  A magnetic field obtained by synthesizing a high-frequency magnetic field and a second external magnetic field, that is, a second high-frequency superimposed magnetic field is applied to the second magnetization free layer 125. The direction of the second magnetization of the second magnetization free layer 125 changes according to the direction of the second effective magnetic field acting on the second magnetization free layer 125. In the present embodiment, the direction of the second effective magnetic field matches or substantially matches the direction of the second high-frequency superimposed magnetic field.

  In the present embodiment, one end of the output signal line 8 is electrically connected to the antiferromagnetic layer 123 </ b> B of the magnetization fixed portion 123. The output signal line 8 transmits the high frequency output signal generated in the magnetoresistive effect element 102 to the output port 4.

  In the present embodiment, the DC current line 15 includes a first line portion 15A and a second line portion 15B. One end of the first line portion 15 </ b> A is electrically connected to the first electrode 11. The other end of the first line portion 15 </ b> A is electrically connected to the second electrode 12. One end of the second line portion 15B is electrically connected to a portion between one end and the other end of the first line portion 15A. The other end of the second line portion 15B is electrically connected to the direct current input terminal 16. The first electrode 11 is in contact with the first end face 102 a of the magnetoresistive effect element 102. The second electrode 12 is in contact with the second end face 102 b of the magnetoresistive effect element 102. In terms of circuit configuration, the magnetoresistive effect element 102 is located between the DC current input terminal 16 and the choke coil 14. A direct current is input to the direct current input terminal 16, and this direct current is supplied to the magnetoresistive effect element 102.

  When the filter device 1 is operated, a DC current source 17 is provided between the DC current input terminal 16 and the ground electrode 13 as shown in FIG. Thereby, a closed circuit including the direct current source 17, the direct current input terminal 16, the direct current line 15, the magnetoresistive effect element 102, the output signal line 8, the choke coil 14, and the ground electrode 13 is formed. The direct current source 17 generates a direct current flowing through this closed circuit. The direct current supplied to the magnetoresistive effect element 102 flows in the direction from the first magnetization free layer 121 toward the magnetization pinned portion 123 and in the direction from the second magnetization free layer 125 toward the magnetization pinned portion 123. It is divided into current and passes through the magnetoresistive element 102.

  Here, the material of each layer constituting the magnetoresistive effect element 102 will be described. The first and second magnetization free layers 121 and 125 of the magnetoresistive effect element 102 are made of the same ferromagnetic material as the first and second magnetization free layers 21 and 23 in the first embodiment. . The materials of the first and second spacer layers 122 and 124 of the magnetoresistive effect element 102 are the same as those of the spacer layer 22 in the first embodiment.

  The first and second magnetization fixed layers 123A and 123C of the magnetization fixed part 123 are made of a ferromagnetic material. As the ferromagnetic material constituting the first and second magnetization fixed layers 123A and 123C, for example, a high spin polarizability material such as Fe, Co, Ni, NiFe, FeCo, FeCoB, or a Heusler alloy is used. The thickness of the first and second magnetization fixed layers 123A and 123C is preferably in the range of 1 to 10 nm.

The antiferromagnetic layer 123B of the magnetization fixed portion 123 is made of an antiferromagnetic material. As the antiferromagnetic material constituting the antiferromagnetic layer 123B, for example, any of FeO, CoO, NiO, CuFeS ₂ , IrMn, FeMn, PtMn, Cr, and Mn is used.

  Next, the first to fourth magnetization directions will be described with reference to FIGS. 17 and 18. In the following description, the first to fourth magnetization directions are represented by symbols D1, D2, D3, and D4, respectively. FIG. 18 shows the first to fourth magnetization directions D1, D2, D3, and D4. 17 and 18 show the X, Y, and Z directions shown in FIG. 2 in the first embodiment. In the present embodiment, one direction perpendicular to both surfaces of the magnetization fixed portion 123 (the direction toward the upper side in FIG. 17) is defined as the Z direction.

  As shown in FIG. 17, the first magnetization free layer 121 and the conducting wire 61 of the first external magnetic field application unit 6 are arranged in this order in the Z direction. The conducting wire 61 extends in the Y direction. When operating the filter device 1, the power source V <b> 1 is connected to the conducting wire 61 so that a current flows in the conducting wire 61 in the direction opposite to the Y direction. In this case, the direction of the first external magnetic field is the X direction. FIG. 18 shows a state in which the direction D1 of the first magnetization coincides with the direction of the first external magnetic field (X direction).

  Moreover, as shown in FIG. 17, the conducting wire 71 and the second magnetization free layer 125 of the second external magnetic field application unit 7 are arranged in this order in the Z direction. The conducting wire 71 extends in the Y direction. When operating the filter device 1, the power supply V <b> 2 is connected to the conducting wire 71 so that a current flows in the Y direction in the conducting wire 71. In this case, the direction of the second external magnetic field is the X direction. Therefore, the direction of the second external magnetic field coincides with the direction of the first external magnetic field. FIG. 18 shows a state in which the direction D2 of the second magnetization coincides with the direction of the second external magnetic field (X direction).

  As shown in FIG. 18, the third magnetization direction D3 of the first magnetization fixed layer 123A and the fourth magnetization direction D4 of the second magnetization fixed layer 123C are both in the Y direction. Therefore, the direction of the first external magnetic field is orthogonal to the third magnetization direction D3, and the direction of the second external magnetic field is orthogonal to the fourth magnetization direction D4.

  Next, the operation and effect of the filter device 1 according to the present embodiment will be described. In the present embodiment, the energy applying unit 5 applies energy to the magnetoresistive element 102 to cause the first and second magnetizations to vibrate based on the high-frequency input signal. In the present embodiment, the energy is a high frequency magnetic field. The direction of the high-frequency magnetic field is different from the directions of the first and second external magnetic fields, for example, the direction orthogonal to the directions of the first and second external magnetic fields.

  When a high frequency magnetic field is applied to the magnetoresistive effect element 2, the direction of each effective magnetic field acting on the first and second magnetizations changes at the frequency of the high frequency input signal. As a result, the respective damping torques acting on the first and second magnetizations change. Thereby, the first and second magnetizations vibrate at the frequency of the high-frequency input signal so that their directions D1 and D2 change. As a result, the relative angle between the first magnetization direction D1 and the third magnetization direction D3 changes, the resistance value of the first path changes, and the second magnetization direction D2 and the fourth magnetization. The relative angle in the direction D4 changes, and the resistance value of the second path changes. The high-frequency output signal corresponds to a change in resistance value of the parallel circuit composed of the first path and the second path. That is, when the resistance value of the first path and the resistance value of the second path change, the resistance value of the parallel circuit composed of the first path and the second path changes. As a result, a high frequency output signal having a frequency equal to the frequency of the high frequency input signal is generated.

  The first magnetization free layer 121 has a first ferromagnetic resonance frequency f1, and the second magnetization free layer 125 has a second ferromagnetic resonance frequency f2. In the present embodiment, as in the first embodiment, the magnitudes of the first and second effective magnetic fields are made different from each other by making the magnitudes of the first and second external magnetic fields different from each other, As a result, the first and second ferromagnetic resonance frequencies f1 and f2 can be made different from each other. When the frequency of the high-frequency input signal is equal to the first ferromagnetic resonance frequency f1, ferromagnetic resonance occurs in the first magnetization free layer 121, and the amplitude of vibration of the first magnetization is maximized. When the frequency of the high-frequency input signal is equal to the second ferromagnetic resonance frequency f2, ferromagnetic resonance occurs in the second magnetization free layer 125, and the amplitude of vibration of the second magnetization is maximized.

  Other configurations, operations, and effects in the present embodiment are the same as those in the first embodiment.

[Fifth Embodiment]
Next, a fifth embodiment of the present invention will be described. First, the configuration of the filter device 1 according to the present embodiment will be described with reference to FIG. The configuration of the filter device 1 according to the present embodiment is different from that of the third embodiment in the following points. The filter device 1 according to the present embodiment includes the magnetoresistive effect element 102 described in the fourth embodiment, instead of the magnetoresistive effect element 2 in the third embodiment.

  Moreover, in this Embodiment, the input signal track | line 151 of the energy provision part 105 contains 151 A of 1st line parts, and the 2nd line part 151B. One end of the first line portion 151 </ b> A is electrically connected to the first electrode 11. The other end of the first line portion 151 </ b> A is electrically connected to the second electrode 12. One end of the second line portion 151B is electrically connected to a portion between one end and the other end of the first line portion 151A. The other end of the second line portion 151 </ b> B is electrically connected to the terminal 31 of the input port 3. The first electrode 11 is in contact with the first end face 102 a of the magnetoresistive effect element 102. The second electrode 12 is in contact with the second end face 102 b of the magnetoresistive effect element 102.

  In the present embodiment, one end of the output signal line 8 is electrically connected to the antiferromagnetic layer 123 </ b> B of the magnetization fixed portion 123. The output signal line 8 transmits the high frequency output signal generated in the magnetoresistive effect element 102 to the output port 4.

  In the present embodiment, the direct current input terminal 16 is electrically connected to the second line portion 151 </ b> B of the input signal line 151. When the filter device 1 is operated, a direct current source 17 is provided between the direct current input terminal 16 and the ground electrode 13 as shown in FIG. Thereby, a closed circuit including the direct current source 17, the direct current input terminal 16, the input signal line 151, the magnetoresistive effect element 102, the output signal line 8, the choke coil 14, and the ground electrode 13 is formed. The direct current source 17 generates a direct current flowing through this closed circuit. The direct current supplied to the magnetoresistive effect element 102 flows in the direction from the first magnetization free layer 121 toward the magnetization pinned portion 123 and in the direction from the second magnetization free layer 125 toward the magnetization pinned portion 123. It is divided into current and passes through the magnetoresistive element 102.

  Next, the operation and effect of the filter device 1 according to the present embodiment will be described. In the present embodiment, the energy application unit 105 applies energy to the magnetoresistive element 102 to cause the first and second magnetizations to vibrate based on the high-frequency input signal. In the present embodiment, the energy is a high frequency input signal. The high-frequency input signal is superimposed on the direct current flowing through the magnetoresistance effect element 102 and applied to the magnetoresistance effect element 102.

  When the high-frequency input signal is applied to the magnetoresistive effect element 102, the current density in the first magnetization free layer 121 and the current density in the second magnetization free layer 125 change with the frequency of the high-frequency input signal. The respective spin transfer torques acting on the first and second magnetizations vary with the frequency of the high frequency input signal. Thereby, the first and second magnetizations vibrate at the frequency of the high-frequency input signal so that their directions D1 and D2 change. As a result, the relative angle between the first magnetization direction D1 and the third magnetization direction D3 changes, the resistance value of the first path changes, and the second magnetization direction D2 and the fourth magnetization. The relative angle in the direction D4 changes, and the resistance value of the second path changes. As a result, the resistance value of the parallel circuit composed of the first path and the second path changes, and a high frequency output signal having a frequency equal to the frequency of the high frequency input signal is generated.

  In the present embodiment, as in the fourth embodiment, the first and second ferromagnetic resonance frequencies f1 and f2 can be changed by changing the magnitudes of the first and second external magnetic fields. .

  Other configurations, operations, and effects in the present embodiment are the same as those in the third or fourth embodiment.

  In addition, this invention is not limited to said each embodiment, A various change is possible. For example, the external magnetic field application unit in the present invention may include one or more electromagnets instead of one or more conductors, or may include one or more permanent magnets.

  In the fourth and fifth embodiments, since the direction of the first external magnetic field and the direction of the second external magnetic field coincide with each other, instead of the first and second external magnetic field application units 6 and 7, One external magnetic field application unit may be provided.

  In the fourth and fifth embodiments, the direction of the second external magnetic field may be different from the direction of the first external magnetic field, for example, the direction opposite to the direction of the first external magnetic field. .

  DESCRIPTION OF SYMBOLS 1 ... Filter apparatus, 2 ... Magnetoresistive element, 3 ... Input port, 4 ... Output port, 5 ... Energy provision part, 6 ... 1st external magnetic field application part, 7 ... 2nd external magnetic field application part, 8 ... Output signal line, 11 ... first electrode, 12 ... second electrode, 13 ... ground electrode, 14 ... choke coil, 15 ... DC current line, 16 ... DC current input terminal, 17 ... DC current source, 21 ... first 1 magnetization free layer, 22 ... spacer layer, 23 ... second magnetization free layer, 51, 52, 53, 54, 55 ... line portion.

Claims (11)

A magnetoresistive element;
An input port to which a high-frequency input signal is applied;
An output port where a high frequency output signal appears;
A filter device comprising an energy applying unit,
The magnetoresistive element includes a first magnetization free layer having a first magnetization, and a second magnetization free layer having a second magnetization,
The direction of the first magnetization changes according to the direction of the first effective magnetic field acting on the first magnetization free layer,
The direction of the second magnetization changes according to the direction of the second effective magnetic field acting on the second magnetization free layer,
The energy applying unit applies energy to the magnetoresistive element for generating vibration based on the high-frequency input signal in the first magnetization and the second magnetization,
The filter device, wherein the high-frequency output signal is caused by vibrations of the first magnetization and the second magnetization.   The filter device according to claim 1, wherein ferromagnetic resonance frequencies of the first magnetization free layer and the second magnetization free layer are different from each other.   3. The apparatus according to claim 1, further comprising at least one external magnetic field application unit configured to apply an external magnetic field to at least one of the first magnetization free layer and the second magnetization free layer. Filter device. The at least one external magnetic field application unit includes a first external magnetic field application unit that applies a first external magnetic field to the first magnetization free layer, and a second external magnetic field application unit to the second magnetization free layer. A second external magnetic field application unit for applying an external magnetic field;
The filter device according to claim 3, wherein the first external magnetic field and the second external magnetic field have different sizes.   4. The filter device according to claim 1, wherein the first magnetization free layer and the second magnetization free layer have different magnitudes of magnetic anisotropy magnetic fields acting on them. 5. .   6. The filter device according to claim 1, wherein the energy applying unit applies a high frequency magnetic field generated based on the high frequency input signal to the magnetoresistive element as the energy.   6. The filter device according to claim 1, wherein the energy applying unit applies the high-frequency input signal to the magnetoresistive effect element as the energy.   The said magnetoresistive effect element further contains the spacer layer arrange | positioned between the said 1st magnetization free layer and the said 2nd magnetization free layer, The Claim 1 thru | or 7 characterized by the above-mentioned. Filter device.   The filter device according to claim 8, wherein the high-frequency output signal corresponds to a change in a resistance value of the magnetoresistive element. The magnetoresistive element further includes a magnetization pinned portion disposed between the first magnetization free layer and the second magnetization free layer, and between the first magnetization free layer and the magnetization pinned portion. A first spacer layer disposed; and a second spacer layer disposed between the second magnetization free layer and the magnetization pinned portion;
The filter device according to claim 1, wherein the magnetization fixed unit includes at least one magnetization fixed layer having magnetization whose direction is fixed.   The high-frequency output signal includes a first path that passes through the magnetization fixed portion, the first spacer layer, and the first magnetization free layer, the magnetization fixed portion, the second spacer layer, and the second The filter device according to claim 10, wherein the filter device corresponds to a change in resistance value of a parallel circuit including a second path passing through the magnetization free layer.

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