KR20160149483A

KR20160149483A - Energy Harvesting Device

Info

Publication number: KR20160149483A
Application number: KR1020150086524A
Authority: KR
Inventors: 이동건; 장광엽; 이동렬; 이승찬
Original assignee: 한국산업기술대학교산학협력단
Priority date: 2015-06-18
Filing date: 2015-06-18
Publication date: 2016-12-28

Abstract

The present invention discloses an energy harvesting device. The energy harvesting device of the present invention includes: a triboelectric generating unit generating triboelectricity; A magnetic body disposed on the first electrode of the triboelectric generating portion; A frame part for accommodating the triboelectric generating part and the magnetic body; And a cold portion and a heat source portion disposed above and below the frame portion to overlap with the magnetic body.
Therefore, the energy harvesting device of the present invention has an effect of converting triboelectric energy into dynamic energy so that the magnetic material having a magnetic characteristic varying with temperature can be moved repeatedly, and generating triboelectric energy by using it.

Description

[0001] Energy Harvesting Device [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an energy harvesting device, and more particularly, to an energy harvesting device that generates triboelectricity by using a magnetic material that changes into a paramagnetic material or a ferromagnetic material depending on a temperature.

Energy harvesting is a technology that converts the energy in the environment into electricity by harvesting.

There are various forms of energy around us, such as heat, vibration, light, and radio waves. Most of the energy is in a lean state and is not being utilized effectively. Energy harvesting is a technology that harvests unused energy and transforms it into an easy - to - use form of power.

Among the energy harvesting devices, a triboelectric nanogenerator has attracted the attention of many researchers because of its excellent power characteristics. The nanogenerator was first reported by the Zhong Lin Wang group of the Georgia Institute of Technology.

The power characteristics of the nano generator using the triboelectricity are largely determined by three factors.

First, it is the material that generates the triboelectricity and determines how many surface charges can be induced.

And the distance between the two substances plays an important role. Finally, the surface area between the two materials increases. As the surface area becomes wider, the charge inducing area becomes wider and thus the overall charge increases, thereby increasing the voltage and current characteristics.

An object of the present invention is to provide an energy harvesting device which converts heat energy into dynamic motion, generates triboelectric energy, and uses it as electric energy.

It is another object of the present invention to provide an energy harvesting device which converts triboelectric energy into kinetic energy so as to move the magnetic body repeatedly in accordance with temperature and generates triboelectric energy by using it.

According to an aspect of the present invention, there is provided an energy harvesting device comprising: a triboelectric generating unit generating triboelectric energy; A magnetic body disposed on the first electrode of the triboelectric generating portion; A frame part for accommodating the triboelectric generating part and the magnetic body; And a cold portion and a heat source portion disposed above and below the frame portion to overlap with the magnetic body.

Here, the triboelectricity generation unit may include: a first electrode having one end and the other end fixed to both side walls of the frame unit; An electricity generating layer disposed on the first electrode; And a second electrode disposed on the electricity generating layer, wherein the first electrode includes a first irregular portion composed of a plurality of irregular patterns, and the electricity generating layer has a plurality of And a second concave-convex portion made of concave-convex patterns.

In addition, the electricity generating layer is made of a material to which a negative electric charge is induced, the magnetic substance is disposed on the upper surface of the first electrode, the magnetic substance is inserted into the through hole formed in the first electrode, And exposed to the upper and lower portions of the first electrode.

In addition, when the magnetic material reciprocates between the cold source and the heat source, the first electrode repeats separation and contact with the electricity generating layer, the magnetic material becomes a paramagnetic material above the Curie temperature, and below the Curie temperature, And the heat source unit includes a magnetic material having a magnetic force.

The energy harvesting device of the present invention has an effect of converting heat energy into dynamic motion to generate triboelectric energy and using it as electric energy.

In addition, the energy harvesting device of the present invention has an effect of converting triboelectric energy into dynamic energy so that a magnetic body having a magnetic characteristic varying with temperature can be moved repeatedly, and generating triboelectric energy by using it.

1 is a view showing a structure of an energy harvesting device according to a first embodiment of the present invention.
2A and 2B are diagrams for explaining the principle of generating triboelectricity in the energy harvesting device of the present invention.
FIGS. 3A and 3B illustrate operation of an energy harvesting device according to a first embodiment of the present invention.
4A and 4B are graphs showing voltage and current characteristics generated in the energy harvesting device according to the first embodiment of the present invention.
FIG. 5 is a graph showing a voltage characteristic according to a distance between an electrode and a triboelectric generation layer in an energy harvesting device according to the first embodiment of the present invention.
6 is a view showing a structure of an energy harvesting device according to a second embodiment of the present invention.
7A and 7B are views showing an operation of an energy harvesting device according to a second embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and the manner of achieving them, will be apparent from and elucidated with reference to the embodiments described hereinafter in conjunction with the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims.

The shapes, sizes, ratios, angles, numbers, and the like disclosed in the drawings for describing the embodiments of the present invention are illustrative, and thus the present invention is not limited thereto. Like reference numerals refer to like elements throughout the specification. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

In the case where the word 'includes', 'having', 'done', etc. are used in this specification, other parts can be added unless '~ only' is used. Unless the context clearly dictates otherwise, including the plural unless the context clearly dictates otherwise.

In interpreting the constituent elements, it is construed to include the error range even if there is no separate description.

In the case of a description of the positional relationship, for example, if the positional relationship between two parts is described as 'on', 'on top', 'under', and 'next to' Or " direct " is not used, one or more other portions may be located between the two portions.

In the case of a description of a temporal relationship, for example, if a temporal posterior relationship is described by 'after', 'after', 'after', 'before', etc., 'May not be contiguous unless it is used.

The first, second, etc. are used to describe various components, but these components are not limited by these terms. These terms are used only to distinguish one component from another. Therefore, the first component mentioned below may be the second component within the technical spirit of the present invention.

It is to be understood that each of the features of the various embodiments of the present invention may be combined or combined with each other, partially or wholly, technically various interlocking and driving, and that the embodiments may be practiced independently of each other, It is possible.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the size and thickness of the device may be exaggerated for convenience. Like reference numerals designate like elements throughout the specification.

1 is a view showing a structure of an energy harvesting device according to a first embodiment of the present invention.

1, an energy harvesting device 100 according to a first embodiment of the present invention includes a triboelectric generating portion 110 composed of a first electrode 150, an electricity generating layer 151 and a second electrode 152, A magnetic body 160 disposed on the first electrode 150 of the triboelectricity generating unit 155 and a cooling unit 120 and a heat source unit 150 disposed on the upper and lower sides of the magnetic body 160, And a frame unit 101 for receiving and fixing the triton generating unit 155, the cold source unit 120, and the heat source unit 130.

The first electrode 150 of the triboelectric generating unit 155 is fixed at one end and the other end to opposing inner sidewalls of the frame unit 101, Respectively.

The electricity generating layer 151 and the second electrode 152 of the triboelectric generating unit 155 are stacked on the first electrode 150 while being fixed to one side of the frame unit 101.

Particularly, the electricity generating layer 151 is fixedly contacted with the second electrode 152, and the magnetic substance 160 disposed on the first electrode 150 with the first electrode 150 moves up and down Contact and separation occur repeatedly.

The triboelectricity generating unit 155 may repeatedly cause contact and separation between the first electrode 150 and the electricity generating layer 151 so that the first electrode 150 and the second electrode 152 And a negative charge (-) is induced in the electricity generating layer 151 to generate triboelectricity.

Therefore, the electricity generating layer 151 of the triboelectric generating unit 155 may be made of polyacrylonitrile, acrylonitrile-vinyl chloride, PC (polybisphenol) Carbonate, Polychloroether, Polyvinylidine chloride (Saran), Polystyrene, Polyethylene, Polypropylene, Polyimide, Kapton, PVC, Polydimethylsiloxane and Polytethrafluoroethylene. And the like.

The first electrode 150 and the second electrode 152 of the triboelectric generating unit 155 may be made of a conductive metal such as copper (Cu), aluminum (Al), silver (Ag), or the like .

The second electrode 152 of the triboelectric generating unit 155 is in contact with the electricity generating layer 151 when the first electrode 150 is in contact with or separated from the electricity generating layer 151 And the electric generation layer 151 is fixed.

The cooler 120 and the heat source 130 are disposed on the upper side and the lower side of the frame unit 101 and face each other with the first electrode 150 and the magnetic body 160 interposed therebetween.

These are placed on top of each other with the magnetic substance 160 disposed on the first electrode 150 of the triboelectric generating unit 155.

That is, the magnetic body 160, the cooler 120, and the heat source 130 are disposed parallel to a vertical line with respect to the center of the frame 101, and the heat source 130 has magnetic properties &Lt; / RTI >

When the magnetic body 160 is lower than the Curie temperature based on the Curie temperature, the magnetic body 160 becomes a ferromagnetic body by obtaining a magnetic force. When the magnetic body 160 is higher than the Curie temperature, the magnetic body 160 becomes a paramagnetic body. Therefore, the magnetic substance 160 disposed on the first electrode 150 is kept parallel to the lower or upper surface of the frame portion 101 by the elastic force of the first electrode 150 before the magnetic force is obtained .

That is, the first electrode 150 maintains a parallel state with the lower surface or the upper surface of the frame portion 101 due to the inherent elastic force, and the magnetic substance 160 is disposed on the first electrode 150 .

The first electrode 150 and the electricity generating layer 151 of the triboelectric generating unit 155 are in contact with each other and the first electrode 150 Is brought into contact with the cold portion 120 disposed on the side surface of the frame portion 101. As shown in FIG.

The temperature of the magnetic substance 160 is lowered by the cold section 120 when the magnetic substance 160 is in contact with the cold section 120. When the temperature of the magnetic substance 160 is lower than the Curie temperature, (160) obtains a magnetic force (becomes a ferromagnetic body). When the magnetic body 160 obtains a magnetic force, a magnetic attractive force acts on the heat source unit 130 disposed on the lower side of the frame unit 101 and the magnetic body 160 moves toward the frame unit 101 Move.

Accordingly, the first electrode 150 moves to the lower surface of the frame portion 101 by the movement of the magnetic body 160, whereby the electricity generating layer 151 and the first electrode 15 are separated from each other .

When the magnetic substance 160 is positioned in the region of the heat source 130 by a magnetic attraction force, the temperature of the magnetic substance 160 rises above the Curie temperature by the heat source 130, (160) loses its magnetic force.

When the magnetic body 160 loses its magnetic force, the first electrode 150 is in a horizontal state in the frame portion 101 in the original state due to the elastic force of the first electrode 150, The first electrode 150 is in contact with the electricity generating layer 151.

That is, when the temperature rises or falls on the basis of the Curie temperature in a state where the magnetic body 160 is superimposed on the cooler 120 and the heat source 130, the cooler 120 and the heat source 130, respectively.

As described above, when the magnetic body 160 reciprocates between the cooler 120 and the heat source 130, the first electrode 150 fixed to the magnetic body 160 also reciprocates up and down, Separation and contact of the first electrode 150 and the electricity generating layer 151 occur. Accordingly, a triboelectric is generated between the first electrode 150, the electricity generating layer 151, and the second electrode 152 due to charge transfer.

As described above, the energy harvesting device of the present invention has the effect of converting heat energy into dynamic motion, generating frictional electricity, and using it as electric energy.

2A and 2B are diagrams for explaining the principle of generating triboelectricity in the energy harvesting device of the present invention.

Referring to FIGS. 2A and 2B, the principle of triboelectric generation by mechanical motion is that an electricity generating layer EGL is disposed between a first electrode layer EL1 and a second electrode layer EL2 and any one electrode layer, When the first electrode layer EL1 and the electricity generating layer EGL are physically brought into contact with each other and separated from each other, triboelectricity is generated by surface friction between the electrode layer EL and the electricity generating layer EGL.

The electrogenerated layer (EGL) is a material in which two different materials easily lose electrons due to external energy such as friction or contact, become positively charged (+), or electrons can easily be obtained and become negatively charged (-). desirable. For example, the electrogenerated layer (EGL) may be formed of a material selected from the group consisting of polyacrylonitrile, acrylonitrile-vinyl chloride, PC (polybisphenol carbonate), polychloroether, polyvinylidine chloride (Saran), polystyrene ), Polyethylene, polypropylene, polyimide, Kapton, PVC, polydimethylsiloxane (PDMS), and polytetrafluoroethylene (PTFE).

As shown in the figure, when the first electrode layer EL1 contacts the electricity generating layer EGL, a positive charge is induced in the first electrode layer EL1 and the second electrode layer EL2, A negative electric charge is induced in the layer EGL and a current I flows from the second electrode layer EL2 toward the first electrode layer EL1.

Conversely, when the first electrode layer EL1 is separated from the electricity generating layer EGL, it can be seen that the current I flows from the second electrode layer EL2 toward the first electrode layer EL1 .

Therefore, by mechanically repeating the contact and separation between the first electrode layer EL1 and the electrogenerated layer EGL, triboelectricity is continuously generated.

In the present invention, mechanical contact and separation between the first electrode layer (EL1) and the electricity generating layer (EGL) are realized by using a magnetic material, an electrode having elasticity, a cold source and a heat source to generate triboelectricity, .

FIGS. 3A and 3B illustrate operation of an energy harvesting device according to a first embodiment of the present invention.

3A and 3B, an energy harvesting device 100 according to a first embodiment of the present invention includes a first electrode 150, a electricity generating layer 151, and a second electrode 152 A magnetic body 160 disposed on the first electrode 150 of the triboelectric generating unit 155 and a cooling unit 120 disposed on the upper and lower sides of the magnetic body 160, And a frame unit 101 for fixing the heat source unit 130 and the frictional electricity generation unit 155, the cold source unit 120, and the heat source unit 130.

The first electrode 150 of the triboelectric generating unit 155 is positioned parallel to the lower side and the upper side in the frame part 101 by an inherent elastic force. Therefore, the first electrode 150 is electrically connected to the first electrode 150 of the triboelectric generating portion 155 while maintaining surface contact with the electricity generating layer 151 of the triboelectric generating portion 155, Is brought into contact with the cold room part (120) arranged on the side of the frame part (101).

When the magnetic material 160 contacts the cooler 120, the temperature of the magnetic material 160 falls below the Curie temperature and becomes a magnetic force (becomes a ferromagnetic material). When the magnetic substance 160 has a magnetic force, attraction is exerted by the magnetic force of the heat source unit 130 disposed on the lower side of the frame unit 101, and the first electrode 150 contacts the magnetic substance 160, And moves in the direction of the heat source unit 130.

3B, when the magnetic substance 160 moves in the direction of the heat source unit 130 by a magnetic force, the first electrode 150 on which the magnetic substance 160 is placed contacts the heat source unit 130 Contact.

A strong magnetic force acts between the magnetic substance 160 and the heat source 130 with the first electrode 150 interposed therebetween until the magnetic substance 160 loses its magnetic force. And contacts the heat source unit 130.

A plurality of holes may be formed in a region of the first electrode 150 on which the magnetic body 160 is placed to enhance the magnetic force between the magnetic body 160 and the heat source unit 130,

When the first electrode 150 moves to the heat source 130 in a state having a magnetic force, the first electrode 150 is electrically connected to the electricity generating layer 151 of the triboelectric generating unit 155, The contact state is switched to the separated state, and triboelectricity is generated in the electricity generating layer 151.

3B, if the magnetic substance 160 is present in the heat source 130, the magnetic substance 160 is heated by the heat source 130 to a temperature equal to or higher than the Curie temperature, . 3A, when the magnetic body 160 loses its magnetic force in the region of the heat source 130, the magnetic force of the magnetic body 160 is restored in parallel with the lower surface of the frame 101 by the elastic force of the first electrode 150. [ do.

When the first electrode 150 is restored to its original state, the magnetic substance 160 is again brought into contact with the cold portion 120 and the first electrode 150 is brought into contact with the electricity generating layer 151.

As described above, the energy harvesting device of the present invention has an effect of continuously generating frictional electricity by lowering or raising the temperature of the magnetic material, or by losing or losing the magnetic force.

4A and 4B are graphs showing voltage and current characteristics generated in the energy harvesting device according to the first embodiment of the present invention. FIG. 5 is a graph showing voltage and current characteristics generated in the energy harvesting device according to the first embodiment of the present invention. And the triboelectric generation layer according to the present invention.

4A and FIG. 5, the voltage and current of the triboelectricity generated in the energy harvesting device 100 of the present invention are applied to the first electrode 150 of the triboelectric generation unit 155 (Stage 1) when the first electrode 150 is separated from the electricity generating layer 151 (stage 2) and when the first electrode 150 contacts the electricity generating layer 151 from the heat source 130 (stage 1) . &Lt; / RTI >

4A and 4B, when the first electrode 150 of the triboelectric generation unit 155 moves from the stage 1 state to the stage 2 state, the voltage of the triboelectricity is +5 V, And the current has a value of -1.2 [μA] from 0.7 [μA].

However, when the first electrode 150 of the triboelectric generating unit 155 moves from the stage 2 state to the stage 1 state, the voltage of the triboelectricity changes from +18 V to -18 V, It can be seen that the current has a value of 2 [μA] to -1.6 [μA].

5, the larger the gap between the first electrode 150 of the triboelectricity generating unit 155 and the heat source 130 and the cooler 120, the larger the total voltage generated in the triboelectric The size can be seen to increase.

That is, as the gap between the first electrode 150 of the triboelectricity generating unit 155 and the electricity generating layer 151 is large and separation and contact occur, the magnitude of the triboelectricity (voltage Vpp) Is also increasing.

Therefore, in the energy harvesting device 100 of the first embodiment of the present invention, the gap between the first electrode 150 of the triboelectric generating portion 155 and the electricity generating layer 151 is 2 mm or more . And preferably has a value of 2 mm to 5 mm.

FIG. 6 is a view illustrating a structure of an energy harvesting device according to a second embodiment of the present invention. FIGS. 7A and 7B are views showing an operation of an energy harvesting device according to a second embodiment of the present invention. to be.

In the second embodiment of the present invention, the same parts as those of the first embodiment have the same constituent parts. Therefore, the parts not described in the second embodiment are the same as those in the first embodiment of the present invention.

6 to 7B, the energy harvesting device 200 according to the second embodiment of the present invention includes a first electrode 250 including a first irregular portion 250a having a plurality of irregular patterns, A triboelectricity generator 255 comprising an electricity generating layer 251 and a second electrode 252 including a second uneven portion 251a corresponding to the first uneven portion 250a, A magnetic member 260 disposed on the first electrode 250 of the magnetic member 260 and a cold source 220 and heat source 230 disposed on the upper and lower sides of the magnetic member 260, 255, a cold portion 220, and a frame portion 201 for fixing the heat source portion 230.

A plurality of concave and convex patterns are formed on the first concave and convex portions 250a of the first electrode 250 and the first convex and concave portions 250a are formed in the electricity generating layer 251 corresponding to the first electrode 250, A second concavo-convex portion 251a having a plurality of concavo-convex patterns is formed.

The first electrode 250 and the electricity generating layer 251 are in contact with the first irregular portion 250a and the second irregular portion 251a so that the first electrode 250 250 and the electricity generating layer 251 is wider than that of the first embodiment in which uneven patterns are not formed.

When the contact area between the first electrode 250 of the triboelectricity generating part 255 and the electricity generating layer 251 is increased, the amount of triboelectricity generated also increases, thereby obtaining more triboelectricity.

The first electrode 250 of the triton generating unit 255 has one end and the other end fixed to the inner side walls facing the frame unit 201, And is disposed parallel to the side surface.

On the first electrode 250, an electricity generating layer 251 and a second electrode 252 are stacked as in the first embodiment of the present invention.

Therefore, the first irregularities 250a of the first electrode 250 and the second irregularities 251a of the electricity generating layer 251 come into contact with each other in a state where the irregular patterns are coupled with each other like gear wheels.

A magnetic substance 260 is disposed on the first electrode 250 of the triboelectric generation unit 255 and the magnetic substance 260 is inserted into the through hole H formed in the center of the first electrode 250 And a part of the magnetic body 260 is exposed in a direction lower than the upper surface of the first electrode 250.

The first electrode 250 and the electricity generating layer 251 of the triboelectric generating unit 255 are periodically and periodically rotated by the magnetic substance 260 between the cold source 220 and the heat source 230 Repeat separation and contact.

Particularly, in the second embodiment of the present invention, the first irregularities 250a of the first electrode 250 and the second irregularities 251a of the electricity generating layer 251 are opposed to each other, And the contact area between the first electrode 250 and the electricity generating layer 251 is larger than that in the first embodiment.

As described above, in the second embodiment of the present invention, the contact area between the first electrode 250 and the electricity generating layer 251 is widened to separate or contact the first electrode 250 and the electricity generating layer 251 , The amount of triboelectricity generated also increases.

A method of driving the energy harvesting device 200 according to the second embodiment of the present invention is such that the magnetic substance 260 disposed on the first electrode 250 of the triboelectric generating portion 255 is electrically connected to the frame portion 201 and the heat source unit 230 disposed on the lower side are arranged to overlap with each other.

The first electrode 250 of the triboelectric generating part 255 is arranged in parallel with the center of the frame part 201 and maintains the contact state with the electricity generating layer 251.

At this time, the magnetic body 260 is brought into contact with the cooling part 220 disposed on the upper side of the frame part 201, and the temperature of the magnetic body 260 falls below the Curie temperature. When the temperature of the magnetic substance 260 is lowered below the Curie temperature, as described in the first embodiment of the present invention, the magnetic substance 260 has a strong magnetic force, and as a result, And moves in the direction of the disposed heat source unit 230.

As described above, when the magnetic substance 260 disposed on the first electrode 250 of the triboelectric generation unit 255 moves in the direction of the heat source unit 230, the first irregularities of the first electrode 250 250a and the second concave-convex portion 251a of the electricity generating layer 251 are separated from each other.

In the second embodiment of the present invention, the magnetic substance 260 is exposed on the upper surface and the lower surface of the first electrode 250 of the triboelectric generation unit 255, and the magnetic substance 260 is electrically connected to the heat source unit 230 Direct contact.

When the magnetic material 260 contacts the heat source 230, the temperature of the magnetic material 260 is higher than the Curie temperature by the heat source 230 and the magnetic material 260 is lost. And moves in the direction of the cold portion 220 by the restoring force of the first electrode 250.

The first electrode 250 and the electricity generating layer 251 are brought into contact again and the magnetic body 260 is also brought into contact with the cold chamber 220, do.

Therefore, in the second embodiment of the present invention, the magnetic force between the magnetic substance 260 and the heat source 230 is stronger than in the first embodiment, so that the first electrode 250 of the triboelectric generator 255 is separated and / The contact is made fast and strong and the triboelectricity is increased.

100: energy harvesting element
101:
120: cold circles
130:
150: first electrode
151: electricity generating layer
152: second electrode
155: triboelectric generator

Claims

A triboelectric generating unit generating triboelectricity;
A magnetic body disposed on the first electrode of the triboelectric generating portion;
A frame part for accommodating the triboelectric generating part and the magnetic body; And
And a cold source and a heat source disposed above and below the frame so as to overlap with the magnetic material.

The apparatus according to claim 1,
A first electrode having one end and the other end fixed to both side walls of the frame portion;
An electricity generating layer disposed on the first electrode; And
And a second electrode disposed on the electrogenerated layer.

3. The method of claim 2,
Wherein the first electrode includes a first irregular portion having a plurality of irregular patterns and the electricity generating layer includes a second irregular portion having a plurality of irregular patterns so as to face the first irregular portion, Harvesting device.

3. The method of claim 2,
Wherein the electricity generating layer is made of a material in which a negative charge is induced.

3. The method of claim 2,
And the magnetic material is disposed on the upper surface of the first electrode.

3. The method of claim 2,
Wherein the magnetic material is inserted in a through hole formed in the first electrode, and a part of the magnetic material is exposed in an upper portion and a lower portion of the first electrode.

3. The method of claim 2,
Wherein the first electrode repeatedly separates and contacts with the electricity generating layer when the magnetic material reciprocates between the cold source and the heat source.

The method according to claim 1,
Wherein the magnetic material becomes a paramagnetic material at a temperature above the Curie temperature and becomes a ferromagnetic material at a temperature below the Curie temperature.

The method according to claim 1,
Wherein the heat source includes a magnetic material having a magnetic force.