KR20210062550A - Mehtod of manufacturing ceramic composite with low resistance including superconductors and the composite thereof - Google Patents

Abstract

The present invention discloses a method for manufacturing a low-resistance ceramic compound containing a superconductor and a compound thereof. The method for manufacturing the low-resistance ceramic compound containing the superconductor according to the present invention comprises: a step (S1) in which elements represented by the chemical formula 1 are sealed in a vacuum state and heated to synthesize a ceramic precursor; and a step (S2) in which a ceramic compound is obtained by removing a crystalline portion of the ceramic precursor. In the chemical formula 1, M_a(Cu_(1-x)Fe_x)_(1-a)(Ch)_b(D)_c, M is a transition metal (Mn, Cr, V, or Fe), typical element (Pb, Sn, Hg), lanthanide (Y, or La) or a combination thereof, Ch (chalcogen, chalcogen element) is O, S, Se, Te, Po or a combination thereof, D is P, As, Sb, Bi or a combination thereof, a is 0.1-0.9, x is 0-0.4, b is 1-3 and c is 0-0.5. According to the present invention, there is an effect that resistivity properties much lower than conventional resistivity properties by including the superconductor can be exhibited.

Description

TECHNICAL FIELD [Method of manufacturing ceramic composite with low resistance including superconductors and the composite thereof]

The present invention relates to a method for producing a low-resistance ceramic compound including a superconductor and a compound thereof, and more particularly, to a low-resistance ceramic compound including a superconductor capable of exhibiting much lower specific resistance than the conventional specific resistance, including a superconductor. It relates to a manufacturing method and a compound thereof.

The modern era has made tremendous progress in the technology of handling electrons as it is called the era of electricity and electronics. In addition to its fundamental aspects, it is in the supply of sufficient electric power based on power generation, transmission, and distribution, and has developed into the technology of primary battery, secondary battery, and wireless power transmission and reception, which are media that can store power, leading to tremendous development in the modern era. It became the driving force to achieve it.

However, the problems that solve the problem of lowering efficiency, which appears as a problem of high direct/high density of semiconductors and the preparation of alternatives to the recently emerged environmental and energy problems, are fundamentally the use of low-resistance materials such as copper and gold. It has come to the point that it is necessary to find a new substance to replace/solve the method that had been solved with.

An area of interest with this approach is the field of high-temperature superconducting, which in 1986, Bednorz and Muller, superconducting materials with significantly higher critical temperatures (Tc) compared to those previously achieved. [Bednorz, et al, ZPhys B 64, 189 (1986)] These materials are ceramics composed of layers of copper oxide separated by buffer cations. In the original compound of Bednotz and Muller (LBCO), the buffer cations are lanthanum and barium. Encouraged by their work and motivated by their own critical temperature measurements under pressure, Paul Chu said, Similar materials were synthesized with the buffering ions yttrium and barium. This material is YBCO and is the first superconductor with a Tc above the boiling point (77K) of liquid nitrogen [Wu, et al, Phys Rev Lett 58, 908 (1987)].

With him The highest critical temperature reported so far is 203.5K, which hydrogen sulfide exhibits at a pressure of 155 GPa [Conventional superconductivity at 203 kelvin at high pressures in the sulfur hydride system. Nature 525, 73 (2015).] There is still a lot of room for technology development in order to commercialize and use the characteristics of low resistance after overcoming the limitations of ceramics such as cracking and cracking.

On the other hand, raw materials used in materials such as solar devices have characteristics of having low resistance as well as UV transmittance, so elements of various combinations have been identified among various types of ceramic materials. These devices also play a very important role in increasing energy efficiency with their low resistance characteristics, and the low resistance of materials is one of the very important themes.

Particularly, among materials composed of chalcogen elements and metals, many materials form a rock-salt structure in which anions and cations are regularly arranged to form an octahedron, most of which are typical semiconductor materials with a narrow band gap. As a (narrow band gap semiconductor), a lot of research is being conducted in the field of optoelectronics.

Here, the resistivity of these materials is an important factor, and many studies have been conducted to lower the resistivity by using various substituents or dopants, but there are limitations.

The first technical problem to be solved by the present invention is to provide a method of manufacturing a low-resistance ceramic compound, including a superconductor, capable of exhibiting a specific resistance property that is much lower than that of the existing specific resistance.

In addition, a second technical problem to be solved by the present invention is to provide a low-resistance ceramic compound capable of exhibiting a specific resistance property that is much lower than that of the existing specific resistance, including a superconductor.

The present invention is to solve the above-described first technical problem, the elements according to the following formula (1) in a vacuum state Preparation of a low-resistance ceramic compound including a superconductor comprising the step of sealing and heating to synthesize a ceramic precursor (S1), and removing the crystalline portion of the ceramic precursor to obtain a ceramic compound (S2). Provides a way.

<Formula 1>

M _a (Cu _1-x Fe _x ) _1-a (Ch) _b (D) _c

(M: transition metal (Mn, Cr, V, or Fe), typical elements (Pb, Sn, Hg), lanthanide (Y, or La), or a combination thereof,

Ch (chalcogen, chalcogen element): O, S, Se, Te, Po, or a combination thereof,

D: P, As, Sb, Bi or a combination thereof,

a: 0.1~0.9,

x: 0~0.4,

b: 1 to 3,

c: 0~0.5)

According to an embodiment of the present invention, the ceramic precursor may include crystalline and amorphous.

According to another embodiment of the present invention, the crystalline material may be diamagnetic or weak paramagnetic.

According to another embodiment of the present invention, the crystalline material is a zinc-blend (ZB) structure or a rock-salt (RS) structure with a zinc-blend structure superimposed on a half-Heusler (HH) structure. ) Or a Heusler (HR) structure.

According to another embodiment of the present invention, the central element of the zinc-blend or half-Heisler or Heisler structure may be M or D in Formula 1.

According to another embodiment of the present invention, the amorphous material may have ferromagnetic properties.

According to another embodiment of the present invention, the amorphous content may be in the range of 20 to 100 wt% due to magnetic separation characteristics.

According to another embodiment of the present invention, in step S2, the content of 20 to 100% by weight of amorphous material may be separated by magnetic force.

According to another embodiment of the present invention, the separation may be performed a plurality of times while increasing the powderiness by pulverizing the precursor.

According to another embodiment of the present invention, the heating temperature in step S1 may be 550 to 1100°C.

According to another embodiment of the present invention, the heating time in step S1 may be 10 to 100 hours.

On the other hand, the present invention provides a low-resistance ceramic compound, characterized in that manufactured by the above-described manufacturing method.

On the other hand, the present invention provides a low-resistance ceramic compound including a superconductor having a composition represented by the following formula (1).

<Formula 1>

M _a (Cu _1-x Fe _x ) _1-a (Ch) _b (D) _c

(M: transition metal (Mn, Cr, V, or Fe), typical elements (Pb, Sn, Hg), lanthanide (Y, or La), or a combination thereof,

Ch (chalcogen, chalcogen element): O, S, Se, Te, Po, or a combination thereof,

D: P, As, Sb, Bi or a combination thereof,

a: 0.1~0.9,

x: 0~0.4,

b: 1 to 3,

c: 0~0.5)

According to an embodiment of the present invention, the ceramic precursor may include crystalline and amorphous.

According to another embodiment of the present invention, the crystalline material may be diamagnetic or weak paramagnetic.

According to another embodiment of the present invention, the crystalline material may be a zinc-blend structure or a half-Heusler (HH) or Heusler (HR) structure in which a zinc-blend structure is superimposed on a rock salt structure. .

According to another embodiment of the present invention, the central element of the zinc-blend, half-Heisler or Heisler structure may be M or D in Formula 1.

According to another embodiment of the present invention, the amorphous material may have ferromagnetic properties.

According to another embodiment of the present invention, the amorphous content may be from 20 to 100 wt% due to magnetic separation characteristics.

According to another embodiment of the present invention, the amorphous material may be separated by magnetic force.

According to another embodiment of the present invention, the separation may be performed multiple times while increasing the fineness of the ceramic compound.

According to the ceramic compound according to the present invention, since it contains a superconductor, there is an effect of exhibiting a specific resistance property that is much lower than that of the existing specific resistance.

1 is a diagram showing the crystal structure of a ceramic compound according to the present invention in three dimensions,
2 is an XRD graph (a) of a ceramic compound precursor according to the present invention and a simulation of a metal-substituted material of lead sulfide having a rock salt (RS) structure. It is displayed on one graph (c),
3 is an XRD graph measured by sequentially removing a crystalline portion from a ceramic compound precursor according to the present invention. It is a graph of the ceramic compound that is secondarily separated by
Figure 4 is a graph of the XRD simulation results for PbS according to the present invention, (a) a complete crystal structure of lead sulfide (PbS), (b) sulfur-defect (S-defect), (c) PbS0.5 It is a graph of the case,
5 is a 2θ and Miller index values for the three main peaks of the present invention,
6 is a crystalline structure of the ceramic compound according to the present invention, which is a structure in which 4a: S, 4b: Pb, 4c: Cu is substituted, (a) a rock salt (RS) structure, (b) a zinc-blend (ZB) structure, (c) It is a diagram showing a half-Hoisler structure (HH),
7 is an IV graph of a sample according to an embodiment of the present invention, in which a general superconductor has a flat section (a constant voltage section according to an increase or decrease of current) in the IV graph, and the content of a superconductor in a mixture of a superconductor and a non-superconductor is If it is less, it indicates that no flat section is observed (limit of detectable superconductor content: >10 ^-9 V% for ^{MAMMA, >10 -2} V% for susceptibility, and only drop (transition) is observed for IV. For >~20 V%, when observing zero resistance >~40 V%, refer to the following paper for the limit of volume %, Search for Superconductivity in Micrometeorites, Nature (Sci. Rep.) 4, 7333 (2014), Electrical Transport and Lowered Percolation Threshold in YBa2Cu3O7-δ-Nano-YBa2ZrO5.5 Composites, Inter.J. Supercond., 768714 (2014), SmBa2NbO6 Nanopowders, an Effective Percolation Network Medium for YBCO Superconductors, ADV MATER SCI ENG, 578434 (2013), Electrical transport and superconductivity in Au-YBa2Cu3O7 percolation system, Phys. Rev. B38, 776(1988)),
8 shows a susceptibility data pattern showing a superconductor of a sample according to an embodiment of the present invention,
9 is a graph showing a pattern of MAMMA of a conventional superconductor, as MAMMA data of a sample, which decreases after increasing (a), increases -> decreases -> increases -> decreases (b), increases after decrease (c), Is decrease (d),
FIG. 10 is a graph in which MAMMA data is standardized near room temperature of a sample according to an embodiment of the present invention, and the point indicated by a peak is the actual data. In general, when a peak-shaped data value is obtained in spectroscopy, the exact graph shape ( Profile) is appropriately profiled (fitting), and the profiling functions used are Gaussian (gaussian) and Lorentzian (lorentzian), and Gaussian is used for a symmetrical peak shape, and Lorentz is It is used for an asymmetric shape. In general, in spectroscopy, the peak is slightly asymmetric rather than symmetric for various reasons, so it is profiled with a lorentzian function.

Hereinafter, the present invention will be described in detail.

However, it should be noted that the technical terms used in the present invention are only used to describe specific embodiments and are not intended to limit the present invention.

In addition, the technical terms used in the present invention should be interpreted as generally understood by those of ordinary skill in the technical field to which the present invention belongs, unless otherwise defined in the present invention, and is excessively comprehensive. When the technical term used in the present invention is an incorrect technical term that does not accurately express the idea of the present invention, the technical term used in the present invention is a technical term that can be correctly understood by those skilled in the art. It should be replaced and understood, and the general terms used in the present invention should be interpreted as defined in the dictionary or according to the context before and after, and should not be interpreted as an excessively reduced meaning, and the singular number used in the present invention The expression of the expression includes a plurality of expressions unless clearly defined otherwise in the context, and in the present invention, terms such as "consisting of" or "comprising" necessarily include all of the various elements or various steps described in the present invention. It should not be construed as, and some of the components or some steps may not be included, or it should be construed as that it may further include additional components or steps. If it is determined that the detailed description may obscure the subject matter of the present invention, the detailed description will be omitted.

1 is a diagram showing the crystal structure of a ceramic compound according to the present invention in three dimensions, and FIG. 2 is an XRD graph (a) of a ceramic compound precursor according to the present invention and a metal-substituted material of lead sulfide having a rock salt (RS) structure. Simulation XRD (XRD simulation of metal-substituted PbS) graph (b) is shown in one graph (c) to compare, Figure 3 is measured by sequentially removing the crystalline portion from the ceramic compound precursor according to the present invention As an XRD graph, (a) a ceramic compound precursor, (b) a ceramic compound first separated according to the Example, and (c) a graph of a ceramic compound secondarily separated according to the Example, and FIG. 4 is a PbS according to the present invention. As a graph of the XRD simulation results for, (a) a complete crystal structure of lead sulfide (PbS), (b) a sulfur-defect (S-defect), and (c) a graph in the case of _{PbS 0.5, and FIG. 5 is} 2θ and Miller index values for the three main peaks of the invention, and FIG. 6 is a crystalline structure of the ceramic compound according to the present invention, in which 4a: S, 4b: Pb, 4c: Cu is substituted, ( a) a rock salt (RS) structure, (b) a zinc-blend (ZB) structure, (c) a half-Heisler structure (HH), and FIG. 7 is an IV graph of a sample according to an embodiment of the present invention. , FIG. 8 shows a susceptibility data pattern representing a superconductor of a sample according to an embodiment of the present invention, and FIG. 9 is a graph showing a pattern of MAMMA of a typical superconductor. ), increase->decrease->increase->decrease (b), increase after decrease (c), decrease (d), and FIG. 10 is a graph of standardizing MAMMA data near room temperature of a sample according to an embodiment of the present invention But refer to this.

The method for preparing a low-resistance ceramic compound according to the present invention includes the steps of synthesizing a ceramic precursor by sealing and heating the elements according to the following formula (1) in a vacuum state (S1), and removing amorphous material from the ceramic precursor to obtain a ceramic compound. There are features including step S2.

<Formula 1>

M _a (Cu _1-x Fe _x ) _1-a (Ch) _b (D) _c

(M: transition metal (Mn, Cr, V, or Fe), typical elements (Pb, Sn, Hg), lanthanide (Y, or La), or a combination thereof, and Ch (chalcogen, chalcogen element): O, S, Se, Te, Po, or a combination thereof, D: P, As, Sb, Bi or a combination thereof, a: 0.1 to 0.9, x: 0 to 0.4, b: 1 to 3 And c: 0~0.5)

Here, the above-described x: 0 ~ 0.4, b: 1 ~ 3, c: 0 ~ 0.5 in the description of the numerical value '0' means that it can exist ^{in a very small amount (e.g., 10 -10 ~),} It can be understood as including the meaning of'nothing'.

That is, if x=0, c=0 in _{Ma(Cu 1-x} Fe _x ) _1-a (Ch) _b (D) _{c , then Ma(Cu) 1-a} (Ch) _b is represented by Formula 4 However, the applicant's experiment starts with Formula 4 and adjusts the ratio of Dopant (D), that is, the step M _a (Cu) _{1 in which the superconductor characteristics are expressed by experimenting when x = 0 and c ≠ 0. -a} (Ch) _b (D) _{c is a} step M a (Cu ₁₎ that is the basis for controlling the content of Fe to change the transition metal Cu, which is expected to play a major role, as well as that it can represent the formula 3 _-x Fe _x ) _1-a (Ch) _b, that is, from Formula 2 corresponding to the state x≠0, c=0, by adjusting the ratio of Dopant (D) in the same manner as described above, that is, x This is because even in the case of ≠0 and c≠0, the superconductor characteristics are changed or expanded.

<Formula 2>

M _a (Cu _1-x Fe _x ) _1-a (Ch) _b

<Formula 3>

M _a (Cu) _1-a (Ch) _b (D) _c

<Formula 4>

Ma(Cu)1-a(Ch)b

On the other hand, in general, perovskite is a typical structure of a material that exhibits low resistance characteristics.Since Cu as a central metal forms an octahedral structure made by bonding of six oxygen atoms around, high-temperature superconductors have both Cu and O. However, as the chalcogen elements, sulfur (S), selenium (Se), and tellurium (Te), as the size of the atom itself increases, 6 elements cannot be arranged around Cu like perovskite, and about 4 are arranged. I can.

When the composition of Formula 1 is mixed and heated, a chemical reaction occurs, and the material produced by cooling after the reaction for a certain period of time is a ceramic precursor, which is a material including a crystal domain and an amorphous domain.

Here, the crystalline substance exhibits diamagnetic or weak paramagnetic (diamagnetic or weak paramagnetic), and the crystalline substance has a rock salt structure, and as can be seen in FIG. 1, there are three types of PbS structures: α, β, and γ. Among them, the α-type has a rock salt (RS) structure, and the crystallinity of the ceramic compound precursor according to the present invention may be arranged by substituting Cu, Fe, Bi, or As in the rock salt structure for the central element in the formula (1). There is, for example, M(Pb), Cu, Fe, etc. as a cation, and Ch(S), D(P), etc. as an anion.

In addition, referring to FIG. 2, FIG. 2A is an XRD graph of a ceramic compound precursor according to a preparation example of the present invention, and XRD results for a portion (crystalline portion) that does not have a magnetism are shown as a metal of lead sulfide having a rock salt (RS) structure. When compared with the simulation XRD (metal-substituted PbS XRD simulation) graph (b) of the substituted material (c), the two graphs agree very accurately (here, the small peaks between 30° and 50° are side reactants. It is judged as CuS).

In addition, in the present invention, since it is necessary to separate the amorphous part from the crystalline and the amorphous material, it is separated by grinding into various powders, but the amorphous material has ferromagnetic properties, so that the amorphous material can be separated using magnetic force. Amorphous powders can be adsorbed and separated by the attraction of a magnet.

In addition, the amorphous content can represent a weight ratio with respect to the crystalline substance, which is relative as a boundary value that can be obtained experimentally, and amorphous is a state that is slightly unstable compared to the crystalline sample because the structure is broken due to a defect of sulfur. Although this is not a possible situation and the synthesis conditions are insufficient sulfur, most of the reactants are considered to have a stable structure by taking sufficient sulfur, and it is understood that some reactants in the structure including defective sulfur are amorphized due to lack of sulfur. .

In this respect, if the characteristics of the common mass ratio are experimentally inferred, amorphous properties can be strengthened or weakened, but the conversion from crystalline to amorphous is defined as a weight ratio of about 20 to 100% of the ceramic compound separated by magnetism. It may be, at which time the crystallinity will correspond to 0 to 80% by weight.

In other words, since it is necessary to separate the relatively high amorphous content (20-100wt%), which shows remarkably amorphous properties in the above-described crystalline and amorphous, it is pulverized into various powders, so that the amorphous is ferromagnetic. Separation by adsorbing powders with relatively high amorphous content (20 ~ 100 wt%) from crystalline and amorphous materials with the attraction of a magnet using magnetic force to separate the portion with relatively high amorphous content (20 ~ 100wt%) can do.

In addition, the separated powders with a high amorphous content (20 to 100 wt%) are less than 10 wt% in a small amount for the remaining crystalline or powders with a low amorphous content (20% or less) after being separated, that is, 9: It is usually obtained with a weight ratio of 1.

In addition, if necessary to improve the purity of the amorphous part, the powder is separated by magnetic force in a small state, that is, in a relatively coarse powder state, and then again pulverized and separated. It can be separated while increasing the purity of, and this can be confirmed through FIG. 3.

That is, it can be seen that the purity of the amorphous is improved as the crystalline portion is removed from the ceramic compound.

In addition, in the manufacturing method according to the present invention, in order to improve the purity of the reactants of the ceramic compound, the heating temperature may be 550 to 1100°C. If it is less than 550°C, the elements cannot be sufficiently liquefied and thus reacted by mixing uniformly. A domain that cannot be performed may occur. Conversely, if it exceeds 1100℃, damage or breakage may occur in the reactor, mainly quartz tube, during the reaction due to an increase in pressure, and a situation in which the reaction is not uniform may occur. Unlike the liquefaction that does not liquefy at low temperatures and unreacted substances appear, if the environment is created at a high temperature above the upper limit, it may be difficult to properly react due to loss of elements due to evaporation.

In addition, if the heating time is 10 to 100 hours, if it is less than 10 hours, sufficient liquefaction or uniform mixing may be difficult. Conversely, if it exceeds 100 hours, energy is wasted and damage to the reactor port may occur.

On the other hand, the present invention provides a low-resistance ceramic compound including a superconductor having a composition represented by the following formula (1).

<Formula 1>

M _a (Cu _1-x Fe _x ) _1-a (Ch) _b (D) _c

<Formula 2>

M _a (Cu _1-x Fe _x ) _1-a (Ch) _b

<Formula 3>

M _a (Cu) _1-a (Ch) _b (D) _c

<Formula 4>

Ma(Cu) _1-a (Ch) _b

(M: transition metal (Mn, Cr, V, or Fe), typical elements (Pb, Sn, Hg), lanthanide (Y, or La), or a combination thereof,

Ch (chalcogen, chalcogen element): O, S, Se, Te, Po, or a combination thereof,

D: P, As, Sb, Bi or a combination thereof,

a: 0.1~0.9,

x: 0~0.4,

b: 1 to 3,

c: 0~0.5)

Here, the ceramic compound can observe the change in resistance characteristics according to the partial weight of the crystalline, but when the sulfur defect (S defect) occurs, it is difficult to maintain the rock salt (RS) structure any more, and the structure is deformed. There are two modified forms, one is a crystal structure of an XRD intensity ratio rather than an RS structure, and the other is an amorphous form.Referring to FIGS. 4, 5 and 6, in the case of sulfur-defective PbS ( b) In the graph, the intensity of (111) and (220) is a large pattern, but this form is difficult to obtain in the RS structure.

This point, the crystal structure may be related to the zinc-blend (ZB) structure or the half-Heisler (HH) structure and the Hoisler (HR) structure, and the half-Heisler structure is rock salt (RS) and zinc-blend. The (ZB) structure is a combined structure.

That is, as for the sulfur (S) coordination number for the metal element, the rock salt (RS) is 6 and the zinc-blend (ZB) is 4, and if a sulfur defect (S defect) occurs, a zinc-blend structure with a small S coordination number can be expected. If the sulfur defect becomes severe, it is difficult to maintain the zinc-blend structure. In this case, the metals gather in one space and share the same S. This structure is a Heisler structure, so the crystal structure becomes amorphous when the sulfur defect is deepened. It can be seen that the amorphous structure according to the present invention may be closer to the half-Heisler or Hoisler structure.

On the other hand, when the composition of Formula 1 is mixed and heated, a chemical reaction occurs, and the material produced by cooling after the reaction for a certain period of time is a ceramic precursor, and a material including a crystal domain and an amorphous domain is do.

Here, the crystalline material exhibits diamagnetic or weak paramagnetic (diamagnetic or weak paramagnetic), and the crystalline material may have a rock salt structure, and a more detailed description will be replaced with the content described in the above manufacturing method.

In addition, in the present invention, it is necessary to separate the amorphous part from the crystalline and the amorphous material, and the description thereof will also be replaced with the contents described in the manufacturing method.

Example

In Chemical Formulas 1 to 4, Pb for M, S for Ch, and P for D, the total weight according to the molar ratio in the range of 0.1 to 0.9 for a, 0 to 0.4 for x, 1 to 3 for b, and 0 to 0.5 for c Put 3g into a quartz tube, make a vacuum of 10 ^-5 Torr with a vacuum pump, and after holding for 20 minutes, make the total length of the tube 15cm, seal it with a torch, and seal the quartz tube in a furnace chamber. The ceramic precursor was synthesized by placing it in a reaction temperature of 550°C to 1100°C and a reaction time of 10 to 100 hours. Next, the prepared ceramic precursor was pulverized using a mortar, and the samples separated by the magnetic force of a neodymium magnet were collected and ceramic. A compound was obtained, and the additionally obtained ceramic compound was further pulverized to collect samples that were secondarily separated with a neodymium magnet to obtain a ceramic compound.

Experimental Example 1 Component Analysis (ICP-AES)

Components of the examples were analyzed using a component analysis equipment (equipment name: Inductively Coupled Plasma Atomic Emission Spectrophotometer).

The components of the sample separated by the examples were Pb:Cu:S:P = 0.40: 0.60: 0.55: 0.06 by mass ratio, and at this time, the component of the sample remaining as a nonmagnetic substance was Pb:Cu:S:P = 0.40: 0.60: 0.90: 0.05. Converted value).

Experimental Example 2 XRD analysis

Examples were analyzed using an XRD laboratory equipment (equipment name: Multi-Purpose X-ray Diffractometer).

3, the bottom graph is a graph of the ceramic precursor synthesized according to Preparation Example, the second graph is a graph of the ceramic compound first separated by the Example, and the top graph is 2 according to the Example. It is a graph of the separated ceramic compound, and as can be seen from this, it can be seen that the peak intensity is very low amorphous.

Experimental Example 3 4-probe resistivity measurement

In order to measure the electrical resistance of the sample according to the example, a physical property measurement system (PPMS) was used.

As can be seen in Fig. 7, the value measured at room temperature for the ceramic compound secondarily separated according to the example is 0.0302 Ω, which is converted into specific resistance (Equation: the cross-sectional area of the sample pellet is A, the length is L, and the resistance is In the case of R, a specific resistance ρ = R·A/L), and a specific resistance of about 0.0015 (~ 0.0015) Ωcm was obtained.

The minimum resistivity of Cu-doped PbS known so far is 0.13Ω·cm, and when the doping amount exceeds 5wt%, the resistivity value does not decrease any more and becomes constant. Therefore, it can be seen that the resistivity value is 100 times lower than the previous one (see https://www.researchgate.net/publication/322406660_Deposition_of_Cu-doped _ PbS _thin_films_with_low_resistivity_using_DC_sputtering)

Through this, it can be seen that the specific resistance value of the ceramic compound (amorphous part) according to the embodiment is a very low value that can be obtained from powder pellets and is almost similar to that of copper. (In the case of copper, powder pellets are made to measure the specific resistance. ^{If lower, it is 10 -3} ~10 ^-2 Ωcm due to the increase in contact resistance between powders)

Considering that most ferromagnetic materials are used as an insulator and a semiconductor, the ceramic compound according to the present invention exhibits a much lower resistance than the conventionally known RS structure material due to the amorphous part. It can be seen that it has structure and physical properties.

In addition, the ceramic compound according to the present invention is determined to have a short range order similar to that of a zinc-blend arrangement, half-Heisler or Heusler structure due to amorphous properties, and this structure has low resistance due to metallic ferromagnetism shown by the present invention. It can also be described as having

Experimental Example 4 Magnetization measurement

In order to measure the susceptibility of the sample according to the example, a measuring device (MPMS3-Evercool (Quantum Design Inc.)) was used.

At this time, the measuring magnetic field of the equipment was 0.12Oe.

The magnetic field unit'Oe' is used interchangeably with'gauss', but strictly Oe indicates the strength of the magnetic field, and gauss indicates the strength of the magnetic field induced by flowing electrons through the wire.

In this experiment, Oe is used to indicate the strength of the external magnetic field (denoted as H) applied from the outside (for reference, the geomagnetic is about 0.2~0.3Oe, https://en.wikipedia.org/wiki/%). EC%97%90%EB%A5%B4%EC%8A%A4%ED%85%9F).

The sample according to the present invention needs to apply a very small magnetic field in order to detect the diamagnetic transition, which is a characteristic of a superconductor, in competition with ferromagnetic because it has superconductivity and ferromagnetic properties at the same time. Occurs back and forth.

The second second transition appears below -50°C. This is when the first transition is weakened and recovered by the vortex generated in the superconductor. That is, the competition area between the vortex state and the diamagnetic state (-50°C~50°C) is This is a phenomenon seen because when the vortex is weakened, it returns to its original diamagnetic state.

(This second-order transition has already been reported in the existing superconductor, and the second-order transition for the Bi2212 superconductor: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392017000501406)

In the susceptibility measurement, the fact that the resistance transition is not observed even though the diamagnetic transition is observed appears to be a problem of percolation (connection between particles), and in this case, it is possible to more precisely determine whether a superconducting phase exists in the sample by using a microwave.

Referring to FIG. 8, after cooling from room temperature to 200K (-73°C) without a magnetic field, the magnetic moment is measured by applying a magnetic field of 0.12Oe and heating to 400K (127°C), which is called ZFC. do.

Then, while maintaining the magnetic field of 0.12Oe, the magnetic moment is measured while cooling to 200K (-73℃) again. This is called FC.

In the case of superconductors, since ZFC applies a magnetic field after cooling, the magnetic field is theoretically 100% shielded by the Meissner effect.

This is possible by generating a magnetic field opposite to the external magnetic field inside the superconductor. This is also called diamagnetism, and has a value increased from the magnetic moment to a negative sign.

In addition, in the case of FC, since an external magnetic field is applied above the critical temperature, that is, in a non-superconducting state, the magnetic field cannot be shielded and penetrates into the sample. It is in a shielded state, which weakens the anti-magnetism, so it exhibits a smaller negative magnetic moment than that of ZFC.Or, depending on the characteristics of the superconducting material, in FCs, paramagnetism (positive magnetic moment) is also observed without diamagnetism. have.

Experimental Example 5 MAMMA (Magnetically Modulated Microwave Absorption) Measurement

MAMMA of the sample according to the example To measure, a measuring device (electron spin resonance (ESR, JES-FA200)) was used.

When a superconducting material is contained in a non-superconducting matrix, the best measurement method for identifying a superconductor is to use microwaves.

In particular, when measuring microwave absorption according to a temperature change, it is possible to detect not only various magnetic transitions but also a critical temperature due to a superconducting transition.

This is because each material has a different microwave absorption pattern at the temperature at which the transition occurs.

This measurement method is called MAMMA(S) or MFMMS. These two methods are basically the same method, just the difference in terms.

(Reference: MAMMAS (Magnetically Modulated Microwave Absorption Spectroscopy)

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Magnetically Modulated Microwave Absorption Behavior in the Bi-Pb-Sr-Ca-Cu-O/CdS Composite, J. Supercond. Nov. Magn. 28, 1495 (2015)

Magnetic field modulated microwave spectroscopy (MFMMS)

Magnetic field modulated microwave spectroscopy across phase transitions and the search for new superconductors, Rep. Prog. Phys. 77, 093902 (2014)

Search for Superconductivity in Micrometeorites, Nature (Sci. Rep.) 4, 7333 (2014))

9 shows a pattern of MAMMA of a conventional superconductor, from low temperature to high temperature (horizontal axis, right-to-left direction) after increasing (a), increasing -> decreasing -> increasing -> decreasing (b) , After decreasing, increasing (c), decreasing (d).

In general, superconductors show several unique signal types in MAMMA measurement. A common phenomenon is that when the horizontal axis, which is the temperature axis, goes from high temperature to low temperature (from left to right), absorption from the critical temperature (Tc) upwards. There is a characteristic that shows a sudden increase in signal. Considering this, the shape after the increase in signal varies depending on the internal state of the superconductor, and can be divided into the following three types.

①Peak type (Fig. (a), (b)): decrease after increase

②Undulatory type (Fig. (c)): After increasing, slightly decreasing and then increasing again

③Monotonous type (Fig. (d)): Continuously increasing without decreasing

Therefore, when a sample is measured, if it matches one of the patterns shown in FIG. 9, it can be seen that a superconducting phase exists in the sample (Reference: Non Resonant Microwave Absorption (NRMA) Anomalies in High Temperature Superconductors (HTS) Relevance of Electromagnetic Interactions (EMI) and Energy Stabilized Josephson (ESJ) Fluxons, GK Padam (2012))

FIG. 10 is MAMMA data for this sample, and it can be seen that a superconducting phase with a critical temperature of about 40°C exists as a peak type.

It can be seen that this is a temperature almost consistent with the about 50°C transition obtained in the susceptibility measurement previously.

Claims (21)

Sealing the elements according to Formula 1 below in a vacuum state and heating to synthesize a ceramic precursor (S1);
A method for producing a low-resistance ceramic compound including a superconductor, comprising: removing the crystalline portion of the ceramic precursor to obtain a ceramic compound (S2):
<Formula 1>
M _a (Cu _1-x Fe _x ) _1-a (Ch) _b (D) _c
(M: transition metal (Mn, Cr, V, or Fe), typical elements (Pb, Sn, Hg), lanthanide (Y, or La), or a combination thereof,
Ch (chalcogen, chalcogen element): O, S, Se, Te, Po, or a combination thereof,
D: P, As, Sb, Bi or a combination thereof,
a: 0.1~0.9,
x: 0~0.4,
b: 1 to 3,
c: 0~0.5)
The method of claim 1,
The method of manufacturing a low-resistance ceramic compound including a superconductor, wherein the ceramic precursor comprises crystalline and amorphous.
The method of claim 2,
The method of manufacturing a low-resistance ceramic compound comprising a superconductor, wherein the crystalline material is diamagnetic or weak paramagnetic.
The method of claim 3,
The crystalline material is a zinc-blend structure or a zinc-blend structure with a zinc-blend structure superimposed on a half-Hoisler or Heisler structure, characterized in that the method for producing a low-resistance ceramic compound comprising a superconductor.
The method of claim 4,
A method for producing a low-resistance ceramic compound including a superconductor, characterized in that the central element of the zinc-blend, half-Heisler or Hoisler structure is M or D in the formula (1).
The method of claim 2
The method of manufacturing a low-resistance ceramic compound including a superconductor, wherein the amorphous material has ferromagnetic properties.
The method of claim 2,
The method for producing a low-resistance ceramic compound including a superconductor, wherein the amorphous content is 20 to 100 wt% in a magnetically separated state.
The method of claim 1,
A method of manufacturing a low-resistance ceramic compound including a superconductor, characterized in that the amorphous material is separated by magnetic force in step S2.
The method of claim 8,
The separation is a method for producing a low-resistance ceramic compound including a superconductor, characterized in that the separation is performed a plurality of times while pulverizing the precursor to increase the fineness.
The method of claim 1,
The heating temperature of the step S1 is 550 to 1100 ℃ method for producing a low-resistance ceramic compound comprising a superconductor, characterized in that.
The method of claim 1,
The heating time of the step S1 is a method for producing a low-resistance ceramic compound comprising a superconductor, characterized in that 10 to 100 hours.
A method of manufacturing a low-resistance ceramic compound comprising a superconductor, characterized in that it is manufactured by the manufacturing method of any one of claims 1 to 11.
A low-resistance ceramic compound comprising a superconductor having a composition according to Formula 1 below:
<Formula 1>
M _a (Cu _1-x Fe _x ) _1-a (Ch) _b (D) _c
(M: transition metal (Mn, Cr, V, or Fe), typical elements (Pb, Sn, Hg), lanthanide (Y, or La), or a combination thereof,
Ch (chalcogen, chalcogen element): O, S, Se, Te, Po, or a combination thereof,
D: P, As, Sb, Bi or a combination thereof,
a: 0.1~0.9,
x: 0~0.4,
b: 1 to 3,
c: 0~0.5)
The method of claim 13,
The ceramic precursor is a low-resistance ceramic compound comprising a superconductor, characterized in that it comprises a crystalline and amorphous.
The method of claim 14,
The crystalline is a low-resistance ceramic compound comprising a superconductor, characterized in that diamagnetic or weak paramagnetic (diamagnetic or weak paramagnetic).
The method of claim 14,
The crystalline material is a zinc-blend structure or a zinc-blend structure superimposed on a zinc-blend structure and a low-resistance ceramic compound comprising a superconductor, characterized in that it has a half-Heisler structure or a Hoisler structure.
The method of claim 16,
A low-resistance ceramic compound comprising a superconductor, characterized in that the central element of the zinc-blend, half-Heisler or Hoisler structure is M or D in Chemical Formula 1.
The method of claim 14
The amorphous is a low-resistance ceramic compound comprising a superconductor, characterized in that it has ferromagnetic properties.
The method of claim 14,
A low-resistance ceramic compound comprising a superconductor, wherein the amorphous content is 20 to 100% by weight in a magnetically separated state.
The method of claim 14,
A low-resistance ceramic compound comprising a superconductor, characterized in that the amorphous is separated by magnetic force.
The method of claim 20,
The separation is a low-resistance ceramic compound comprising a superconductor, characterized in that a plurality of times while increasing the fineness of the ceramic compound.

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