Delay element and signal delay method

Abstract

To provide a small-sized delay element with a large delay time.SOLUTION: A delay element 1 is a domain wall motion type delay element and includes a magnetic nanowire 10 made of a magnetic material processed into a thin wire shape, a constant current source 20 that supplies a direct current to the magnetic nanowire 10, a recording element 40 that is arranged directly above or below the magnetic nanowire 10 and records a magnetic domain 15 in the magnetic nanowire 10 on the basis of an input signal, and a detection element 50 that is arranged directly above or below the magnetic nanowire 10 and spaced apart from the recording element 40, and outputs a detection signal for the magnetic domain 15.SELECTED DRAWING: Figure 1A

Description

[Technical field]

[0001] The present invention relates to an element and method for delaying a signal by utilizing the time it takes for a domain wall to move. [Background technology]

[0002] A delay element is a circuit element necessary for processing electrical signals to match timing or provide a time difference. For example, Patent Document 1 describes a tapped surface acoustic wave delay line device that uses a surface acoustic wave delay element. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 11-68500

[0004] The surface acoustic wave delay element is a delay element that utilizes the time it takes for a surface acoustic wave to propagate. As shown in the schematic diagram of Fig. 7, the surface acoustic wave delay element converts an electric signal Ein input from input terminals 801A and 801B into a surface acoustic wave SAW at an input electrode 901. The surface acoustic wave SAW propagates on a piezoelectric substrate 700, is converted into an electric signal Eout at an output electrode 902, and is output from output terminals 802A and 802B. Summary of the Invention [Problem to be solved by the invention]

[0005] Because the propagation speed of surface acoustic waves is several thousand meters per second, surface acoustic wave delay elements can obtain a longer delay time than delay circuits made of electrical circuits. However, the propagation distance must be secured, and there are limitations to further miniaturization.

[0006] The present invention has been made to solve the above problems, and has an object to provide a small-sized delay element having a large delay time. [Means for solving the problem]

[0007] The delay element of the embodiment comprises a magnetic nanowire made of a magnetic material processed into a thin wire shape, a constant current source that supplies a direct current to the magnetic nanowire, a recording element that is arranged directly above or below the magnetic nanowire and records a magnetic domain in the magnetic nanowire based on an input signal, and a detection element that is arranged directly above or below the magnetic nanowire and spaced apart from the recording element, and outputs a detection signal of the magnetic domain.

[0008] In addition, the signal delay method of the embodiment supplies a direct current to a magnetic nanowire made of a magnetic material processed into a thin wire, records a magnetic domain in the magnetic nanowire based on the input signal, and outputs a detection signal of the magnetic domain moved by the direct current. Effect of the Invention

[0009] According to the present invention, it is possible to provide a small-sized delay element having a large delay time. [Brief description of the drawings]

[0010] [Figure 1A] FIG. 2 is a plan view illustrating an outline of a delay element according to the first embodiment. [Figure 1B] FIG. 1B is a cross-sectional view taken along line IB-IB in FIG. 1A. [Diagram 2] 1 is a graph illustrating an input signal. [Figure 3A] 1 is a cross-sectional view illustrating a state in which a magnetic domain is formed on one end side of a magnetic nanowire. [Figure 3B] 1 is a cross-sectional view illustrating a state in which a magnetic domain moves in a magnetic nanowire. [Figure 3C] 11 is a cross-sectional view illustrating a state in which a magnetic domain has moved to the other end side of the magnetic nanowire. FIG. [Figure 4A] FIG. 4 is a plan view illustrating a modified example of the first embodiment. [Figure 4B] 13 is a plan view illustrating a connection to an external power supply in a modified example of the first embodiment. FIG. [Diagram 5] FIG. 11 is a cross-sectional view illustrating an outline of a delay element according to a second embodiment. [Figure 6]1 is a flowchart illustrating a signal delay method according to an embodiment. [Figure 7] FIG. 2 is a plan view illustrating an outline of a surface acoustic wave delay element. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] [First embodiment] A delay element 1 according to a first embodiment will be described with reference to Fig. 1A and Fig. 1B. The delay element 1 is a domain wall motion type delay element that delays an output signal Sout with respect to an input signal Sin by utilizing the time required for domain wall motion. As illustrated in Fig. 1A, when a drive current ID is applied to a magnetic nanowire 10 in which a magnetic domain 15 is formed, the magnetic domain 15 moves (drives) in the extension direction of the magnetic nanowire 10. The delay element 1 delays a signal by utilizing the time required for this motion.

[0012] Magnetic domain 15 is a section of magnetic wire 10 where the magnetization direction is uniform. The magnetization direction of magnetic domain 15 is uniform across the width of magnetic wire 10. Before magnetic domain 15 is formed, magnetic wire 10 is magnetized in a constant direction different from the magnetization direction of magnetic domain 15, and domain walls are formed at both ends of magnetic domain 15 in the extension direction of magnetic wire 10. A domain wall is a region where the magnetization direction gradually changes. Magnetic domain 15 and domain walls move due to driving current ID. This phenomenon in which magnetic domain 15 and domain walls move due to driving current ID is called the current-induced domain wall motion phenomenon. Here, the magnetic domain 15 moves in the direction of the arrow A1, which is opposite to the direction of the driving current ID. Even in the case where the movement of the magnetic domain 15 is the focus of the description, the magnetic domain wall moves together with the magnetic domain 15.

[0013] The delay element 1 includes a magnetic wire 10, a constant current source 20, a recording element 40, and a detection element 50. Here, the magnetic wire 10, the recording element 40, and the detection element 50 are formed on a common substrate 70. The magnetic wire 10, the recording element 40, and the detection element 50 are insulated by an insulating layer 30. The delay element 1 also includes input terminals 81A and 81B to which an input signal Sin is input, and output terminals 82A and 82B to which an output signal Sout is output. Each component of the delay element 1 will be described below.

[0014] (magnetic thin wire) The magnetic nanowire 10 is a member made by processing a magnetic material into a fine wire shape. The magnetic material here is a ferromagnetic material or a ferrimagnetic material that has spontaneous magnetization. Note that ferromagnetism and ferrimagnetism refer to the property of having magnetization in which the magnetic moment is aligned even in the absence of an external magnetic field. The magnetic nanowire 10 is a film-like element whose width is wider than its thickness, and is formed in a thin wire shape that is sufficiently long relative to its thickness and width. A perpendicular magnetization film, whose magnetization direction is likely to be oriented in the thickness direction, can be used as the magnetic nanowire 10. The perpendicular magnetization film is formed from a material with perpendicular magnetic anisotropy. This allows the magnetization direction of the magnetic domain 15 to be one of two types, upward or downward in the thickness direction, which can correspond to a binary signal. Note that the direction from the substrate 70 toward the magnetic nanowire 10 is described as upward.

[0015] The magnetic nanowire 10 may be a multilayer film such as a Co / Pd multilayer film in which layers of transition metals such as Fe, Co, Ni, etc. and layers of precious metals such as Pd and Pt are alternately and repeatedly laminated. The magnetic nanowire 10 may also be a single layer film or a multilayer film of an alloy (RE-TM alloy) of a rare earth metal and a transition metal such as Tb-Fe-Co or Gd-Fe, or an L10 ordered alloy such as FePt or FePd. The speed at which the magnetic domains 15 and the magnetic domain walls move in the magnetic nanowire 10 (hereinafter referred to as the magnetic domain wall motion speed) varies depending on the material of the magnetic nanowire 10. The delay element 1 can be made smaller by forming the magnetic nanowire 10 from a material with a slow magnetic domain wall motion speed. It is desirable for the magnetic domain wall motion speed to be, for example, several m / s or less. Examples of materials with a slow magnetic domain wall motion speed include a Co / Tb multilayer film, a Co / Pd multilayer film, and a Co-Pt alloy.

[0016] The domain wall motion speed is proportional to the current density of the drive current ID in the magnetic wire 10 (hereinafter referred to as the drive current density). The drive current density is the magnitude of the drive current ID divided by the cross-sectional area of ​​the magnetic wire 10. Therefore, the domain wall motion speed can also be adjusted by the magnitude of the drive current ID and the cross-sectional area of ​​the magnetic wire 10. Neither the width nor the thickness of the magnetic wire 10 is particularly limited, but the width can be, for example, 10 nm to 10 μm, and the thickness can be, for example, 3 nm to 30 nm. The magnetic nanowire 10 can be formed into a thin wire by forming a film by a known method such as sputtering, and then processing the film into a thin wire shape by combining photolithography, electron beam lithography, etching, lift-off, etc. The magnetic nanowire 10 may have a layer for protecting the magnetic nanowire 10 from oxidation or a layer for adjusting magnetism on the upper or lower surface side. An insulating member may be provided so as to cover the side surface of the magnetic nanowire 10.

[0017] (constant current source) The constant current source 20 is an element that supplies a direct current to the magnetic nanowire 10. The constant current source 20 is connected to both ends of the magnetic nanowire 10, and continuously supplies a current of constant magnitude and direction. The direct current supplied by the constant current source 20 becomes a driving current ID for the magnetic domain 15. The current value of the constant current source 20 is set so that the drive current density is, for example, 10 6 A / cm 2 From 10 7 A / cm 2 If the driving current density is small, the magnetic domains cannot be driven, and if it is large, problems such as electromigration and heat generation may occur. The driving current density required for the movement of the magnetic domains 15 differs depending on the material of the magnetic nanowire 10, etc.

[0018] (Recording element) The recording element 40 is an element that generates a magnetic field when an electric signal is input. The recording element 40 is disposed directly above or below the magnetic nanowire 10, and records a magnetic domain 15 in the magnetic nanowire 10 according to the input signal. Here, the recording element 40 is disposed directly above one end side of the magnetic nanowire 10. The recording element 40 and the magnetic nanowire 10 are insulated by an insulating layer 30. Here, the recording element 40 is a thin-line conductor and is arranged so as to be perpendicular to the magnetic nanowire 10 in a planar view. A recording current IR flowing through the recording element 40 generates a magnetic field in the thickness direction in the magnetic nanowire 10 adjacent to the recording element 40 in a planar view.

[0019] The magnitude of the recording current IR depends on the material and thickness of the magnetic nanowire 10, but for example, the current density is 1×10 7 A / cm 2 From 3×10 7 A / cm 2 If the magnitude of the recording current IR is insufficient, it is not possible to form the magnetic domains 15. On the other hand, if the recording current IR is large, the range affected by the strong magnetic field becomes wide, and the magnetic domains 15 may become longer than necessary in the extension direction. The recording element 40 is made of a general electrode metal material such as a metal such as Cu, Al, Au, Ag, Ta, or Cr or an alloy thereof, and Au is particularly suitable because of its high conductivity and chemical stability. The recording element 40 is formed into a thin wire shape by a known method such as sputtering, and processed by a combination of photolithography, electron beam lithography, etching, lift-off, and the like.

[0020] Both ends of the recording element 40 are connected to input terminals 81A and 81B. The input terminals 81A and 81B are terminals to which an input signal Sin is input. The recording element 40 generates an upward or downward magnetic field in the magnetic nanowire 10 to record magnetic domains. The input signal Sin may be a signal that takes two values. Here, the input signal Sin is a signal that takes two values, 0 and a positive value, for the recording current IR. When the recording current IR is 0, a small current that does not affect the magnetization direction of the magnetic nanowire 10 may flow. 1A is positive. The positive recording current IR generates a magnetic field in the thickness direction in the vicinity of the detection element 50 side of the magnetic nanowire 10 directly below the recording element 40, and can form a magnetic domain 15 whose magnetization direction is downward.

[0021] (Detection element) The detection element 50 is an element that converts a magnetic signal into an electric signal. The detection element 50 is disposed directly above or directly below the magnetic nanowire 10, separated from the recording element 40, and outputs a detection signal of the magnetic domain 15. Here, the detection element 50 is disposed directly above the other end side (opposite side to the recording element 40) of the magnetic nanowire 10. The detection element 50 and the magnetic nanowire 10 are insulated by the insulating layer 30. Both ends of the detection element 50 are connected to output terminals 82A and 82B. The output terminals 82A and 82B are terminals that output an output signal Sout. The detection element 50 can be a known magnetic head such as a tunnel magnetoresistance (TMR) head or a giant magnetoresistance (GMR) head, or a Hall bar structure. The detection element 50 outputs a detection signal corresponding to a change in the magnetization direction, for example. Here, the detection signal is output as it is as the output signal Sout. If the detection signal is not a binary signal but is, for example, an analog signal whose value changes continuously, the output signal Sout can be converted to a binary signal corresponding to the input signal Sin outside the delay element 1.

[0022] (insulating layer) The insulating layer 30 is disposed between the magnetic wire 10 and the recording element 40 and the detection element 50, and is an insulating layer that insulates the magnetic wire 10 from the recording element 40 and the detection element 50. The material of the insulating layer 30 is, for example, SiO X or AlO X such as an oxide film, SiN X , MgF2 or other known insulating materials can be applied. Here, X in the subscript of O or N indicates that the composition ratio is not limited. SiO X is, for example, SiO2, AlO X is, for example, Al2O3 (X = 1.5), and SiN X is, for example, Si3N4 (X = 1.33). The insulating layer 30 can be formed by film formation using a known method such as sputtering.

[0023] (Substrate) The substrate 70 is a member that serves as a base on which the magnetic fine wire 10, the recording element 40, and the detection element 50 are formed. As the substrate 70, for example, a known substrate such as a Si substrate, a GGG (gadolinium gallium garnet) substrate, a SiC (silicon carbide) substrate, a MgO (magnesium oxide) substrate, an AlN (aluminum nitride) substrate, or a Ge (germanium) single crystal substrate can be used. An insulating layer is provided on the surface of the substrate 70 on the side where the magnetic fine wire 10 and the like are formed, and the magnetic fine wire 10 and the like are formed thereon. This insulating layer may be, for example, an SiO X film formed on the surface of the Si substrate, or a laminated structure of a plurality of layers. Further, the substrate 70 may be a Si substrate having a SiO X film (0 < X ≦ 2) formed by thermal oxidation of the surface. By forming the magnetic fine wire 10 and the insulating layer 30 in this order on the substrate 70 provided with the insulating layer on the surface, and forming the recording element 40 and the detection element 50 on the insulating layer 30, the delay element 1 in which these are formed on the same substrate 70 can be manufactured.

[0024] The delay element 1 having the above configuration can increase the signal delay time and reduce the size by utilizing the time it takes for the domain wall to move. For example, by using a magnetic material with a domain wall movement speed of several m / s, the propagation distance can be reduced to about 1 / 1000 compared to a surface acoustic wave delay element with the same delay time, and the element size can be reduced to about 1 / 1000. Also, a delay time about 1000 times longer can be obtained compared to a surface acoustic wave delay element with the same element size. The manufacturing process of the delay element 1 has good compatibility with the manufacturing process of semiconductor integrated circuits, and the element size can be reduced, making it suitable for incorporation into a semiconductor integrated circuit.

[0025] The constant current source 20 may be a constant current circuit that operates with a constant voltage power supply. The constant current source 20 may be a known constant current circuit that has MOS (metal oxide semiconductor) transistors or bipolar transistors and controls the current flowing through these transistors to be constant. The constant current source 20 may be provided on the substrate 70. The recording element 40 may also have a circuit that generates a recording current I R from the input signal S in. The recording current I R can be generated so that it takes two values, for example, 0 and a positive value large enough to form a magnetic domain, in response to the input signal S in. Furthermore, the detection element 50 may have a circuit for converting an analog signal into a binary signal. The delay element 1 can convert the detection signal, which is an analog signal, into a binary signal corresponding to the input signal Sin and output it as the output signal Sout.

[0026] (Delay element operation) Next, the operation of the delay element 1 will be described with reference to Fig. 2 to Fig. 3C. Here, the input signal Sin is a signal of the recording current IR, and the recording current IR takes two values, 0 and a positive value I1. As illustrated in Fig. 2, the input signal Sin has sections W1 and W2 in which the recording current IR has the positive value I1. The recording current IR changes from the positive value I1 to 0 in section W1 at time t1, and in section W2 at time t2. The time width of section W2 is longer than that of section W1.

[0027] While the recording current IR has a positive value I1, a magnetic domain is formed in the magnetic wire 10. A driving current ID of a constant magnitude is applied to the magnetic wire 10 before the input signal Sin is input, and the formed magnetic domain is driven in the direction of the detection element 50. The length of the magnetic domain in the extension direction of the magnetic wire 10 corresponds to the length of time during which the recording current IR has a positive value I1. Fig. 3A illustrates the magnetic domain 15 at time t1, Fig. 3B illustrates the magnetic domain 15 between time t1 and time t2, and Fig. 3C illustrates the magnetic domain 15 at time t2. Note that before the magnetic domain 15 is formed, the magnetic nanowire 10 is entirely magnetized upward, and the downward magnetic domain 15 is formed by the recording current IR of a positive value I1.

[0028] 3A, at time t1, a magnetic domain 151 is recorded in the magnetic wire 10 near the right side of the recording element 40. The magnetic domain 151 and the detection element 50 are separated by a propagation distance L. The propagation distance L is the distance from the position where the magnetic domain is recorded to the detection element. 3B, between time t1 and time t2, the magnetic domain 151 moves from the recording element 40 toward the detection element 50 at a propagation velocity V. The propagation velocity V is the domain wall motion velocity, which is the speed at which the magnetic domain 15 moves in the extension direction of the magnetic nanowire 10.

[0029] 3C, at time t2, the magnetic domain 151 moves to immediately below the detection element 50. Then, the change in the magnetization direction of the magnetic nanowire 10 is detected by the detection element 50, and is output as an electrical output signal Sout. The signal delay time T can be expressed as T=L / V. Furthermore, at time t2, the next input signal records a magnetic domain 152 near the right side of the recording element 40. The length of the magnetic domain 152 is longer than that of the magnetic domain 151. Thereafter, the magnetic domain 152, like the magnetic domain 151, moves at a propagation velocity V in the direction from the recording element 40 toward the detection element 50.

[0030] (Modification) Next, a modified example of the delay element 1 will be described with reference to Figs. 4A and 4B. As illustrated in Fig. 4A, the delay element 1A according to the modified example is different from the delay element 1 in that the constant current source is a variable constant current source 20A that can change the magnitude of the direct current by a current setting signal, but the other points are the same. The variable constant current source 20A will be described below. In the delay element 1A, the magnetic nanowire 10, the recording element 40, the detection element 50, and the variable constant current source 20A are formed on the same substrate 70. The variable constant current source 20A is an element that continuously supplies a current whose magnitude and direction are constant, similar to the constant current source 20. The variable constant current source 20A can change the magnitude of the current by a current setting signal input from the outside. The variable constant current source 20A has a current setting terminal 83 to which the current setting signal is input. The current setting signal can be a direct current, a direct current voltage, or a digital signal. A plurality of current setting terminals 83 may be provided.

[0031] Domain wall movement speed V M Between V and the drive current density j, M =μ B p j / (e M S ) where μ B is the Bohr magneton, p is the spin polarizability, e is the charge of the electron, M S is the saturation magnetization. Domain wall motion velocity V M is proportional to the drive current density j, and therefore varies with the drive current ID. Therefore, the delay element 1A can adjust the delay time T by a current setting signal input from the current setting terminal 83.

[0032] The variable constant current source 20A can be a constant current circuit that operates with a constant voltage power supply, similar to the constant current source 20. FIG. 4B shows an example of connection to an external constant voltage power supply when the variable constant current source 20A is, for example, a semiconductor integrated circuit on a Si substrate and is formed on the same substrate 70 as the delay element 1A. The delay element 1A has a power supply terminal 84A to which an external power supply is connected and a ground (GND) terminal 84B to which a potential reference is connected. A constant voltage power supply 91 is connected to the power supply terminal 84A, and a predetermined voltage at which the variable constant current source 20A operates is supplied. The input terminals 81A, 81B, the output terminals 82A, 82B, the current setting terminal 83, the power supply terminal 84A, and the GND terminal 84B can be bonding pads of the semiconductor integrated circuit.

[0033] The delay element 1A according to the modified example can increase the signal delay time and achieve miniaturization, similar to the delay element 1. The delay time can be made variable by changing the domain wall motion speed using a current setting signal. 4B, the variable constant current source 20A can be replaced with the constant current source 20. In this case, the current setting terminal 83 is not necessary. In addition, in a delay element in which a constant current circuit operating on a constant voltage power supply is a variable constant current source 20A or a constant current source 20, the constant current circuit may be provided on the power supply side of the magnetic wire 10, as illustrated in Figure 4B, or on the GND side.

[0034] [Second embodiment] Next, a delay element 2 according to a second embodiment will be described with reference to Fig. 5. The delay element 2 differs from the delay element 1 in that it includes a plurality of detection elements 50, but has the same other features as the delay element 1. The plurality of detection elements 50 will be described below. In addition to the detection element 50 in the delay element 1, the delay element 2 further includes one or more detection elements 50 located directly above or below the magnetic nanowire 10 and spaced apart from the detection element 50 in the delay element 1. As illustrated in FIG. 5, the detection element 50 in the delay element 1 is the detection element 51 located farthest from the recording element 40. The delay element 2 includes a total of N detection elements 50. The detection elements 50 in the delay element 2 are all equivalent to the detection elements 50 in the delay element 1.

[0035] The delay element 2 has output terminals corresponding to the multiple detection elements 50 so that an output signal can be output independently from each of the multiple detection elements 50. Each of the multiple detection elements 50 is independently connected to an output terminal. For example, both ends of the detection element 52 adjacent to the detection element 51 are connected to output terminals 82A2 and 82B2, and both ends of the detection element 53 adjacent thereto are connected to output terminals 82A3 and 82B3. The delay element 2 can output multiple output signals. The delay element 2 may include one or more detection elements 50 at positions farther from the recording element 40 than the detection elements 50 in the delay element 1 .

[0036] Similar to the delay element 1 according to the first embodiment, the magnetic domain 15 moves in a direction from the recording element 40 toward the detection element 50 by the driving current ID. The magnetic domain 15 is detected first by the detection element 50 located closest to the recording element 40. Then, after a time interval corresponding to the arrangement interval of the detection elements 50, the magnetic domain 15 is detected by the detection element 50 located next closest to the recording element 40, the detection element 50 located next closest to the recording element 40, and so on. The detection signal may be output as it is as an output signal, or may be converted into a binary signal corresponding to the input signal and output. In either case, the output signals are output in sequence from output terminals 82AN, 82BN to output terminals 82A1, 82B1 at time intervals, and an output signal with a delay time suitable for the purpose can be selected.

[0037] In the delay element 2 according to the second embodiment, a plurality of (N) detection elements 50 are arranged in the extension direction of the magnetic nanowire 10. Since detection can be performed without destroying the magnetic domains 15, different delay times can be obtained from the first output to the Nth output with one delay element 2.

[0038] In addition, in the delay element 2, the constant current source may be the constant current source 20, or may be a variable constant current source 20A. That is, in addition to the detection element 50 in the delay element 1, one or more detection elements 50 are further provided directly above or below the magnetic nanowire 10, away from the detection element 50 in the delay element 1, and the constant current source may be a variable constant current source 20A that can change the magnitude of the direct current by a current setting signal. The delay element 2 uses the variable constant current source 20A as the constant current source, and thereby obtains a plurality of output signals with different delay times, and can adjust the delay time by changing the domain wall motion speed by the drive current ID.

[0039] In any of the first embodiment, the modified example, the second embodiment, and combinations thereof, the magnetic nanowire, the recording element, the detection element, and the constant current source may be formed on the same substrate as a delay element.

[0040] [Signal delay method] Next, a signal delay method S1 according to an embodiment will be described with reference to Fig. 6. As illustrated in Fig. 6, the signal delay method S1 supplies a direct current to a magnetic nanowire formed by processing a magnetic material into a nanowire shape (step S10), records magnetic domains in the magnetic nanowire by the input signal (step S20), and outputs a detection signal of the magnetic domains moved by the direct current (step S30). Each step of the signal delay method S1 will be described below.

[0041] (supplies direct current) First, a direct current is supplied to the magnetic nanowire (step S10). The magnetic nanowire is a magnetic body processed into a thin wire shape. The direct current is supplied in a constant direction and magnitude in the extension direction of the magnetic nanowire, and the subsequent steps are performed while supplying the direct current. The direct current is set to a magnitude that can drive the magnetic domain.

[0042] (recording magnetic domains) Next, magnetic domains are recorded in the magnetic nanowire by the input signal (step S20). Recording of the magnetic domains may be performed by the magnetic field of a current flowing in a linear conductor, as in the delay element 1, or may be performed by a known magnetic head or the like. Before inputting the signal, the magnetic nanowire can be magnetized in a direction different from the magnetization direction of the magnetic domains to be recorded. The recorded magnetic domains are moved by the supplied direct current.

[0043] (Detection signal is output) Then, a detection signal of the magnetic domain moved by the direct current is output (step S30). The detection of the magnetic domain is performed at a position away from the position where the magnetic domain is recorded. The movement of the magnetic domain takes time corresponding to the distance from the position where the magnetic domain is recorded to the position where it is detected. Therefore, the time from when the signal is input to when it is output can be set as the signal delay time.

[0044] The signal delay method S1 utilizes the time it takes for the magnetic domain wall to move to delay the signal, making it possible to miniaturize the delay element and increase the delay time. The delay time can be increased by about 1000 times compared to a surface acoustic wave delay element of the same element size. [Explanation of symbols]

[0045] 1 Delay element (first embodiment) 1A Delay element (variation) 2 Delay element (second embodiment) 10 Magnetic thin wire 15 magnetic domains 20 constant current source 20A variable constant current source 30 Insulating layer 40 Recording element 50 Detector element 70 Substrate 81A Input Terminal 82A output terminal 83 Current setting terminal

Claims

1. a magnetic fine wire obtained by processing a magnetic material into a fine wire shape; a constant current source for supplying a direct current to the magnetic nanowire; a recording element disposed directly above or below the magnetic nanowire and configured to record a magnetic domain on the magnetic nanowire in response to an input signal; a detection element that is disposed directly above or directly below the magnetic nanowire and spaced apart from the recording element, and outputs a detection signal for the magnetic domain;

2. 2. The delay element according to claim 1, wherein the constant current source is a variable constant current source capable of changing the magnitude of the direct current by a current setting signal.

3. The delay element according to claim 1 , further comprising, in addition to the detection element, one or more detection elements spaced apart from the detection element, directly above or below the magnetic nanowire.

4. In addition to the detection element, one or more detection elements are further provided directly above or directly below the magnetic nanowire and spaced apart from the detection element, 2. The delay element according to claim 1, wherein the constant current source is a variable constant current source capable of changing the magnitude of the direct current by a current setting signal.

5. 5. The delay element according to claim 1, wherein the magnetic nanowire, the recording element, the detection element, and the constant current source are formed on the same substrate.

6. A direct current is supplied to a magnetic nanowire, which is a magnetic material processed into a nanowire shape. A magnetic domain is recorded in the magnetic nanowire by an input signal; A signal delay method for outputting a detection signal of the magnetic domain moved by the direct current.

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