KR100725753B1 - A device and a method of amplitude modulation using spin devices - Google Patents

Abstract

An amplitude modulation device using a spin device and a method thereof are provided to improve signal to noise ration(SNR) by reducing low frequency noise(1/f noise) and noise from a transmission line. In an amplitude modulation device, a spin device(20) shows variation of electrical resistance proportional to the intensity of magnetic field. A lead(10) connects the spin devices and is used as a path for inputting a carrier or outputting a modulated wave. A shielding layer surrounds the top, the bottom or the whole structure of the amplitude modulation device. An insulation layer insulates the spin device, the lead and the shielding layer electrically as being located among the spin device, the lead and the shielding layer. The carrier is inputted by connecting the spin devices whose electrical resistance is changed according to external magnetic field, and the amplitude of the carrier is changed according to the magnetic field(modulated wave) applied to the spin device.

Description

Amplitude Modulation Device and Method Using Spin Device {A DEVICE AND A METHOD OF AMPLITUDE MODULATION USING SPIN DEVICES}

1 is an exemplary diagram for explaining amplitude modulation using a transistor according to the prior art.

2 is a conceptual diagram of an amplitude modulation device according to an embodiment of the present invention

3 is a block diagram of an amplitude modulator according to an embodiment of the present invention

4 is a cross-sectional view of FIG. 3

5 is an exemplary plan view of a spin device in an amplitude modulation device according to an embodiment of the present invention;

6 is an exemplary view of the output characteristics according to the input current of the amplitude modulator according to the present invention

7 is another illustration of the output characteristics according to the input current of the amplitude modulation device according to the present invention

** Description of symbols for the main parts of the drawing **

10: wire 20: spin element (GMR)

31: insulation layer 1 32: insulation layer 2

40: female coil 50: cladding

60: shielding layer

The present invention is an amplitude modulation device and method using a spin device that implements amplitude modulation using a spin valve type giant magnetoresistive element (hereinafter referred to as a spin valve) and a magnetic tunnel junction type tunneling magnetoresistive element (hereinafter referred to as a magnetic tunnel junction) as spin elements. It is about.

On the other hand, the present invention belongs to a modulation technique in which the amplitude of a carrier wave is controlled by a modulated wave, that is, a magnetic field, and the amplitude of the carrier wave is changed and output as a modulated wave. This signal belongs to a signal processing technology and a sensor utilization technology for outputting a modulated wave whose amplitude of the carrier is changed. It also belongs to the noise reduction technology which aims to improve the signal-to-noise ratio (SNR) by reducing the low frequency noise (1 / f noise) and the noise flowing from the transmission line.

1 is an exemplary view for explaining amplitude modulation using a transistor according to the prior art. Conventionally, amplitude modulation is implemented using a transistor. For this purpose, a modulated wave is obtained by inputting a modulated wave and a carrier wave to a base of a transistor and configuring an LC circuit resonating at a carrier frequency. In addition, the conventional sensors mainly use a method of investigating resistance according to the environment and physical quantity formed around the sensor by applying a DC voltage or a current, which has a disadvantage of being easily exposed to low frequency noise (1 / f noise).

The present invention has been made to solve the above problems of the prior art, a spin element exhibiting a change in electrical resistance in proportion to the strength of the magnetic field; A conductive line connected to the spin elements in series or in parallel and used as a path for receiving a carrier wave or outputting a modulated wave; A shielding layer surrounding the top, bottom, or entirety of the amplitude modulation element and shielding unnecessary external magnetic fields or electrical noise; Including an insulating layer disposed between the spin element, the conductive wire, the shielding layer to electrically insulate

It is an object of the present invention to provide an amplitude modulation device and a method using a spin device such that the amplitude of the carrier wave changes according to the applied magnetic field strength.

The present invention is an amplitude modulation device and method using a spin device that implements amplitude modulation using a spin valve type giant magnetoresistive element (hereinafter referred to as a spin valve) and a magnetic tunnel junction type tunneling magnetoresistive element (hereinafter referred to as a magnetic tunnel junction) as spin elements. It is about. More specifically, the spin element is connected to the spin element in which the electrical resistance changes according to the external magnetic field in series or in a Wheatstone bridge form to input the carrier wave, and the spin element changes the amplitude of the carrier wave in accordance with the magnetic field (modulation wave) applied to the spin element. It relates to an amplitude modulation device and a method using.

The amplitude modulation element and method using the spin element according to the present invention can be used not only for communication but also for processing, transferring, and converting data in a measurement system, and inducing low frequency noise (1 / f noise) and noise flowing from a transmission line. It can be reduced to improve the signal-to-noise ratio (SNR).

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the amplitude modulation element and method using a spin element according to the present invention.

2 is a conceptual diagram of an amplitude modulation device according to an embodiment of the present invention. As shown in FIG. 2, the amplitude modulation device according to an embodiment of the present invention is to change the amplitude of the carrier wave according to the strength of the magnetic field applied from the outside of the magnetic coupling amplitude modulation device. Modulation is implemented, and for this purpose, the spin element 20 is connected, one end is grounded and the other end is inputted with a carrier wave, while an external magnetic field is inputted to the circuit to obtain a modulation wave.

That is, the amplitude modulator according to the present invention connects the spin element 20 whose electrical resistance changes according to an external magnetic field to a conductor 10, which is a path for receiving a carrier wave or outputting a modulated wave, and inputs a carrier wave. The amplitude of the carrier wave changes according to the magnetic field (modulation wave) applied to the spin element.

On the other hand, in the amplitude modulation device according to the present invention, the spin element for sensing the magnetic field may be connected in series to use a voltage division law, or may be connected in a Wheatstone bridge form. The spin element has a length and width of 100 μm or less, and is manufactured by a vacuum thin film deposition method or a plating method, and after the deposition process, a conventional heat treatment or a high speed heat treatment process is performed. The thermal stability and magnetoresistance characteristics are applied by applying a magnetic field during the heat treatment process. It is desirable to change or improve the

In addition, as a device capable of expressing the electrical resistance as a linear or nonlinear function of the magnetic field, a current-applied magnetization inverting device, spin torque, spin transfer torque, spin momentum transfer ) A spin valve, a magnetic tunnel junction, a spin transistor structure or an element including an effect element is used, and a magnetic field or current applied to the element is used as a modulation wave or carrier wave.

3 is a block diagram of an amplitude modulator according to an embodiment of the present invention. As shown in FIG. 3, the amplitude modulation device according to the embodiment of the present invention generates a magnetic field proportional to the current input to the excitation coil, and applies the excitation coil to the amplitude modulation device.

The amplitude modulation element according to the present invention comprises at least one spin element 20 which exhibits a change in electrical resistance proportional to the strength of the magnetic field; A wire 10 connected to the spin elements in series or in parallel and used as a path for receiving a carrier wave or outputting a modulated wave; A shielding layer surrounding the top, bottom, or entirety of the amplitude modulation element, and shielding unnecessary external magnetic fields or electrical noise; And an insulating layer positioned between the spin element, the conductive wire, and the shielding layer to electrically insulate the insulating layer.

The spin element represents a change in electrical resistance proportional to the strength of the magnetic field generated from an external magnetic field or a flat coil (excited coil) 40 or an excitation conductor installed therein, and according to the structure and properties of the material, In response to the intensity, it has hysteresis, linear and nonlinear magnetoresistance curves. The spin element has a general purpose that can be replaced with a device that can be expressed as a function of the magnetic field in addition to the spin valve and the magnetic tunnel junction, and can generate a magnetic field applied from the outside and a flat coil (excited coil) or a magnetic field therein. Use magnetic fields generated by female conductors.

The insulating layer 30 is positioned between the spin element and the flat coil (excitation coil) or the excitation lead, and between the conducting wire and the shielding layer to electrically insulate each lead and the interlayer.

Meanwhile, the amplitude modulator according to the present invention may further include a flat coil (excited coil) 40 or an excitation lead, and the flat coil (excited coil) 40 or an excitation lead may include the law of ampere and the biosava. According to the law, it generates a magnetic field proportional to the amplitude of voltage or current of modulated wave.

4 is a cross-sectional view of FIG. 3. As shown in FIG. 4, the cross-sectional structure of an amplitude modulator according to an exemplary embodiment of the present invention includes spin element (GMR) (Giant Magneto Resistance) 20 connected to a conductive line 10, on top of the spin element. Insulation layer 1 (31) provided, the excitation coil 40 provided on the upper insulating layer 1, the cladding (Cladding) 50 surrounding the excitation coil, the insulating layer 2 provided on the upper And a shielding layer 60 provided on the insulating layer 2.

On the other hand, the magnetic field focusing layer located around the female conductor or the layer having the effect of focusing the magnetic field around the female conductor has a hexagonal shape or an octagonal structure having a wider center and a narrower or thinner structure as it approaches the electrode of the spin element. desirable. It is also desirable to add a feedback loop to improve linearity.

5 is an exemplary view illustrating a planar structure of a spin device in an amplitude modulation device according to an embodiment of the present invention. As shown in Figure 5, the planar structure of the spin element in the amplitude modulation device according to an embodiment of the present invention is manufactured in a single, parallel connection, series connection type to be applied to digital amplitude modulation, nonlinear amplitude modulation, linear amplitude modulation, etc. Can be.

That is, the spin elements are arranged in a single device, two or more are arranged in parallel, or two or more different line widths are arranged in parallel to adjust coercive force or sensitivity, or two or more are twisted in series. Two or more arranged or different line widths can be used in series in a serpentine form to adjust the coercivity or sensitivity.

6 is an exemplary view of the output characteristics according to the input current of the amplitude modulation device according to the present invention. As shown in Figure 6, the output characteristics according to the input current of the amplitude modulation element according to the present invention can exhibit a linear characteristic.

In the amplitude modulator according to the present invention, as described above, the carrier is input by connecting a spin element whose electrical resistance changes according to an external magnetic field, and the amplitude of the carrier is changed in accordance with a magnetic field (modulation wave) applied to the spin element. Amplitude modulation is performed when the amplitude modulation device has a magnetic resistance of about 10% and an element exhibiting a linear resistance change in the applied magnetic field in the vicinity of 0 Oe.

7 is another exemplary diagram of an output characteristic according to an input current of an amplitude modulator according to the present invention. As shown in FIG. 7, the output characteristic according to the input current of the amplitude modulator according to the present invention may exhibit hysteresis characteristics.

On the other hand, in order to use the latch mode or the memory (memory) mode, a pulse magnetic field having a pulse width of 100 ms or less is used for the spin element of the amplitude modulator according to the present invention, or a flat coil or an excitation conductor of the amplitude modulator. A pulsed current with a pulse width of 100 ms or less is applied to generate a pulsed magnetic field.

The amplitude modulation element has a magnetic resistance of about 50%, and exhibits two resistance states near 0 Oe, that is, a magnetic tunnel junction in which hysteresis characteristics are distinctly used.

In this case, since only two states of amplitude are shown, the measurement can be used to determine the presence of a magnetic field above the coercive force, and the communication can be applied to digital amplitude modulation (ASK). When used for communication, the power saving effect can be expected by using a very short pulse due to the memory characteristics of the magnetic tunnel junction. For example, when the sign is 1 (high potential, high level), the output voltage is Csin ωt and when the sign is 0 (low potential, low level), the output voltage is Dsin ω t . At this time, C and D are determined by the resistance value of the spin valve sensors, and according to the voltage division law, the maximum resistance / (maximum resistance + minimum resistance) or minimum resistance / (maximum resistance + minimum resistance) is multiplied by the amplitude of the carrier wave. Corresponding. Therefore, when the magnetoresistance ratio of the spin valve sensor with the minimum resistance value of 1 가 is 100% and the amplitude of the carrier wave is 2 V, C is 2 / (2 + 1) × 2 = 1.3 V, and D is 1 / (2 + 1 ) × 2 = 0.6 V.

As a result, the amplitude modulation method using the spin element according to the present invention can output the strength of the magnetic field as the amplitude of the carrier wave, output the strength of the current as the amplitude of the carrier wave, and there is no LC or RLC resonant circuit. Is simple, advantageous for integrated circuits, and operates at high frequencies so that low frequency noise can be ignored. In addition, it is possible to reduce the effects of noise introduced or generated in the transmission line, as well as to be applied to various applications using a modulation method such as communication and measurement.

The configuration and operation as described above are not limited to the claims of the present invention as an embodiment, and various changes and modifications are possible within the scope of not changing the technical spirit of the present invention. It is obvious to those who are engaged.

According to the present invention as described above, the amplitude modulation method using the spin element can be used not only for communication but also for processing, transferring and converting data in a measurement system, and low frequency noise (1 / f noise) and noise introduced from a transmission line. It is possible to reduce the frequency of the signal to improve the signal-to-noise ratio (SNR).

Claims (9)

In amplitude modulator, A spin element 20 representing a change in electrical resistance proportional to the strength of the magnetic field; A wire 10 connected to the spin elements in series or in parallel and used as a path for receiving a carrier wave or outputting a modulated wave; A shielding layer 60 surrounding the top, bottom, or entirety of the amplitude modulation element and shielding unnecessary external magnetic fields or electrical noise; At least an insulating layer 30 disposed between the spin element, the conductive line, and the shielding layer to electrically insulate the spin element, the conductive line, and the shielding layer. Amplitude modulation using a spin element characterized in that the carrier is input by connecting the spin element whose electrical resistance changes according to an external magnetic field, and the amplitude of the carrier wave changes according to the magnetic field (modulation wave) applied to the spin element. device The method of claim 1, Amplitude modulation device using a spin device, characterized in that the spin device is connected in series using a voltage division law The method of claim 1, Amplitude modulation device using a spin element, characterized in that the spin element is connected in the form of a Wheatstone bridge delete The method of claim 1, The amplitude modulation element, Amplitude modulation element using a spin element, characterized in that it further comprises a flat coil (excited coil) 40 or an excitation conductor The method of claim 1, The spin element, Amplitude modulation element using a spin element, characterized in that the length and width of each 100㎛ or less The method of claim 1, The amplitude modulation element, Spin elements (GMRs) connected by conductive wires, an insulating layer 1 provided on the spin elements, an excitation coil provided on the insulating layer 1, a cladding surrounding the excitation coil, and an upper portion of the crading Amplitude modulation device using a spin element, characterized in that consisting of an insulating layer 2 provided in the upper, and a shielding layer provided on the insulating layer 2 In the amplitude modulation method using the spin element 20 showing a change in electrical resistance proportional to the strength of the magnetic field, The spin elements are connected in series or parallel, and are used as a path for receiving a carrier wave or outputting a modulated wave, and surround the top, bottom, or whole of an amplitude modulator, and shield unnecessary external magnetic fields or electrical noise. At least an insulating layer disposed between the spin element, the conducting wire, and the shielding layer to electrically insulate the shielding layer, A carrier is inputted by connecting the spin elements in series or in a Wheatstone bridge, and the amplitude of the carrier is varied according to a magnetic field (modulation wave) applied to the spin elements. The method of claim 8, Amplitude modulation method using a spin device, characterized in that for the spin device using a pulse type magnetic field of 100 ms or less pulse width

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