JP5750726B2 - A conductive material, and a resistor paste, a resistor, and a thin film containing the conductive material. - Google Patents

Description

  The present invention relates to a novel conductive material, and a resistor paste, a resistor, and a thin film containing the conductive material.

A resistor paste and a resistor using the resistor paste generally contain a conductive material, an organic vehicle, and further a glass material for adjusting a resistance value and imparting bonding properties as main components. Then, as the conductive material, conventionally, platinum (Pt), a material containing a noble metal such as ruthenium oxide (RuO ₂₎ has been used (for example, Patent Document 1). However, since noble metals are expensive and their resources are limited, alternative materials have been sought.

  The characteristics of the conductive material are required to be stable even in a high-temperature atmosphere, to have a low electrical resistivity, and to have a low resistance temperature coefficient (TCR). In particular, a material having a low electrical resistivity of about 1 mΩcm or less and a low resistance temperature coefficient is required.

  However, a material that does not contain a noble metal and satisfies the above conditions has not been found.

  The present invention has been made in view of the above-mentioned problems of the prior art, and an object thereof is to provide a conductive material having a low electrical resistivity (specific resistance) and excellent TCR (resistance temperature coefficient) characteristics and containing no noble metal. To do.

The present invention is a conductive material having a reduced electrical resistivity by replacing part of the perovskite oxide represented by La ₄ BaCu ₅ O ₁₃ with Pr,
Provided is a conductive material characterized by being represented by La _4-X Pr _X BaCu ₅ O ₁₃ (0.05 ≦ X ≦ 0.60).

  According to the present invention, it is possible to provide a conductive material having a low electrical resistivity and excellent TCR characteristics even though no noble metal component is used.

X-ray diffraction pattern of La ₄ BaCu ₅ O ₁₃ obtained in Example 1 of the present invention and La ₄ BaCu ₅ O ₁₃ obtained by simulation X-ray diffraction pattern of La _3.6 Pr _0.4 BaCu ₅ O ₁₃ obtained in Example 1 of the present invention Temperature Dependence of Electrical Resistivity of La _4-X Pr _X BaCu ₅ O ₁₃ Obtained in Example 1 of the Present Invention Composition dependence of the electrical resistivity at 200 K of La _4-X Pr _X BaCu ₅ O ₁₃ obtained in Example 1 of the present invention Composition dependence of the electrical resistivity at 500 K of La _4-X Pr _X BaCu ₅ O ₁₃ obtained in Example 1 of the present invention The composition dependence of the resistance temperature coefficient at 200K~500K of _{La 4-X Pr X BaCu 5} O 13 obtained in Example 1 of the present invention X-ray diffraction pattern of La ₄ BaCu _4.75 Co _0.25 O ₁₃ obtained in Example 2 of the present invention Temperature dependence of electrical resistivity of La ₄ BaCu _5-Y Co _Y O ₁₃ obtained in Example 2 of the present invention Composition dependency of electrical resistivity at 200 K of La ₄ BaCu _5-Y Co _Y O ₁₃ obtained in Example 2 of the present invention Composition dependence of electrical resistivity at 500 K of La ₄ BaCu _5-Y Co _Y O ₁₃ obtained in Example 2 of the present invention Composition Dependence of Resistance Temperature Coefficient at 200K to 500K of La ₄ BaCu _5-Y Co _Y O ₁₃ Obtained in Example 2 of the Present Invention Changes in electrical conductivity characteristics of La ₄ BaCu ₅ O ₁₃ substrate obtained as a reference sample in Example 3 of the present invention Temperature Dependence of Electrical Conductivity for La ₄ BaCu _5-Y Co _Y O ₁₃ Thin Film Sample Obtained in Example 3 of the Present Invention

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiments, and the following embodiments are not departed from the scope of the present invention. Various modifications and substitutions can be made.
[First Embodiment]
Perovskite oxide can be expected to have low electrical conductivity anisotropy due to its crystal structure, and is stable even in high-temperature air because it is an oxide. For this reason, it can use preferably as an electroconductive material which uses electronic components, such as a resistor.

Among them, La ₄ BaCu ₅ O ₁₃ used as a base material (basic composition) in the present invention has regular oxygen defects in its structure, and has been confirmed to have high conductivity (non- Patent Document 1). Various studies have been made on such substances. For example, a substance in which a part of a Cu site is substituted with Co has been reported (Non-Patent Document 2), but the electrical resistivity is reduced by substitution of Pr or Co. Was not reported.

The inventors of the present invention have a low electrical resistivity (specific resistance) and excellent TCR characteristics by replacing a part of La ₄ BaCu ₅ O ₁₃ having a perovskite structure with a predetermined amount of Pr or Co. As a result, the present invention was completed.

First, in this embodiment, a conductive material in which the electrical resistivity is reduced by replacing part of the perovskite oxide represented by La ₄ BaCu ₅ O ₁₃ with Pr will be described. That is, this is a conductive material represented by La _{4 -X} Pr _X BaCu ₅ O ₁₃ (0.05 ≦ X ≦ 0.60) and is a base material (basic composition) La ₄ BaCu ₅ O. _The electrical resistivity is lower than ₁₃ . In actual compounds, trace amounts of oxygen may be deficient or may exist in excess, so that the composition ratio of oxygen may slightly deviate from 13, for example, 12.65 and 13.35. Therefore, strictly speaking, the above chemical formula is expressed as La _4-X Pr _X BaCu ₅ O _{13 + δ} , but in the present invention, it is expressed as La _4-X Pr _X BaCu ₅ O ₁₃ for the sake of convenience. This includes cases where deficiency or oxygen excess occurs. The same applies to other perovskite oxides in this specification.

The method for producing La _{4 -X} Pr _X BaCu ₅ O ₁₃ is not particularly limited, and can be obtained, for example, by mixing and baking a compound containing an element constituting the above compound.

Specifically, for example, it can be obtained by using La ₂ O ₃ , BaCO ₃ , CuO, and Pr ₂ O ₃ as raw materials, and mixing and baking them so as to achieve the desired product composition ratio. .

  The firing conditions and the like are selected according to the type of raw material and the like, and are not limited. For example, the firing conditions can be obtained by firing in a temperature range of about 800 ° C to 1000 ° C. The firing step can be performed separately in a calcination step and a main firing step. Further, since the product is an oxide, it can be fired in an air atmosphere or an oxygen-rich environment.

Here, as the addition amount of Pr, in the formula represented by La _{4 -X} Pr _X BaCu ₅ O ₁₃ , when it is added to the raw material so as to satisfy 0.05 ≦ X ≦ 0.6, it is compared with the case of no addition Thus, both the electrical resistivity and the temperature coefficient of resistance are preferably about two-thirds or less of the case where no Pr is added. In particular, it is more preferable to add Pr so that 0.05 ≦ X ≦ 0.3 because both the electrical resistivity and the temperature coefficient of resistance are about half or less of those in the case of no addition of Pr.

  And since it uses as an electroconductive material which uses electronic components, such as a resistor, it is preferable that the electrical resistivity in 500K is 1.2 mΩcm or less, and it is more preferable that it is 1.0 mΩcm or less.

Moreover, in order to use with electronic parts, such as a resistor, it is preferable that the change of the resistance value by the temperature change in an actual use temperature range is small. For this reason, the temperature coefficient of resistance in the temperature range of 200K to 500K is preferably 2.5 × 10 ⁻³ mΩcm / K or less, and more preferably 2.0 × 10 ⁻³ mΩcm / K or less.

  The temperature coefficient of resistance α is obtained by dividing the difference in electrical resistivity between 500K and 200K by 300, which is the temperature difference.

  That is, when the electrical resistivity at 500K and 200K is ρ (500K) and ρ (200K), respectively, it was calculated by the equation α = {ρ (500K) −ρ (200K)} / (500−200). Is.

Since La _{4 -X} Pr _X BaCu ₅ O ₁₃ described in this embodiment has low electric resistivity and excellent TCR characteristics, it can be preferably used as a conductive material for various electronic components. Specifically, it can be preferably used as a resistor paste containing the conductive material or a resistor (thick film resistor) containing the conductive material.

Moreover, the thin film containing the said electroconductive material can also be manufactured by well-known thin film manufacturing means, such as a sputtering method and CVD method, and a thin film can also be preferably used for uses, such as an electronic component.
[Second Embodiment]
In this embodiment, a conductive material in which electric resistivity is reduced by replacing part of the perovskite oxide represented by La ₄ BaCu ₅ O ₁₃ with Co will be described. That is, this is a conductive material represented by La ₄ BaCu _{5 -Y} Co _Y O ₁₃ (0.05 ≦ Y ≦ 0.35) and is a base material (basic composition) La ₄ BaCu ₅ O _13. It is a conductive material with a reduced electrical resistivity. As described in the first embodiment, a trace amount of oxygen may be defective or excessive in an actual compound, but the above formula includes such a case.

The method for producing La ₄ BaCu _5-Y Co _Y O ₁₃ is not particularly limited as described in the first embodiment. For example, a compound containing an element constituting the compound is mixed, It is obtained by firing. As specific examples, La ₂ O ₃ , BaCO ₃ , CuO, and CoO are used as raw materials, and these can be obtained by mixing and firing so as to achieve the desired composition ratio of the product. The firing conditions and the like are not limited as described in the first embodiment, and can be appropriately selected depending on the type of raw material.

Here, as the addition amount of Co, when it is added so as to satisfy 0.05 ≦ Y ≦ 0.35 in the formula represented by La ₄ BaCu _5-Y Co _Y O ₁₃ , the electric resistivity and resistance temperature at 500K Both coefficients are preferable because they are smaller than when Co is not added. In particular, it is more preferable to add Co so that 0.05 ≦ Y ≦ 0.25 because the electrical resistivity is lower than the case of no addition between 200 K and 500 K, which is the actual use temperature.

  And since it uses as a conductive material which uses a resistor, an electronic component, etc., it is preferable that the electrical resistivity in 500K is 1.2 mΩcm or less, and it is more preferable that it is 1.0 mΩcm or less.

Moreover, in order to use it with a resistor, an electronic component, etc., it is preferable that the change of the electrical resistivity by the temperature change in an actual use temperature range is small. For this reason, the temperature coefficient of resistance at 200K to 500K is preferably 2.0 × 10 ⁻³ mΩcm / K or less, and more preferably 1.5 × 10 ⁻³ mΩcm / K or less.

Since La ₄ BaCu _{5 -Y} Co _Y O ₁₃ described in this embodiment has low electrical resistivity and excellent TCR characteristics, it can be used as a conductive material for various electronic components. Specifically, it can be preferably used as a resistor paste containing the conductive material and a resistor (thick film resistor) containing the conductive material. Moreover, the thin film containing the said conductive material can also be manufactured by sputtering method, CVD method, etc., and a thin film can also be preferably used for uses, such as an electronic component.
[Third Embodiment]
In this embodiment, a thin film containing a conductive material in which part of a perovskite oxide represented by La ₄ BaCu ₅ O ₁₃ is substituted will be described.

The conductive material in which a part of the perovskite oxide represented by La ₄ BaCu ₅ O ₁₃ described in the first and second embodiments is substituted has a low electrical resistivity and excellent TCR characteristics. Therefore, it can be preferably used in various electronic parts. One form when used in applications such as electronic parts is a method of forming a thin film containing these conductive materials.

There is no particular limitation on the method for thinning the conductive material in which a part of the perovskite oxide represented by La ₄ BaCu ₅ O ₁₃ is substituted, and various film formations (film formation) such as sputtering and CVD are possible. The method can be adopted.

A method for producing a thin film will be described by taking a sputtering method as an example. As a sputtering target, for example, a target of La ₄ BaCu ₅ O _{13 as} a base material and a target of praseodymium oxide or cobalt oxide as an additive component are used. Can be membrane. Specifically, for example, a thin film can be formed by Ar discharge sputtering using, as a target, a target in which an additive component target is placed on a target of La ₄ BaCu ₅ O _{13 as} a base material.

The substrate to be used is not particularly limited, and various substrates such as a quartz substrate, a SrTiO ₃ single crystal substrate, and a Si substrate coated with SiO ₂ on the surface can be used. Among them, a quartz substrate and a SrTiO ₃ single crystal substrate are preferably used because they are excellent in lattice matching with the obtained thin film.

  It is preferable to heat-treat the obtained thin film after the film forming step. This is because the crystallinity in the thin film is poor immediately after vapor deposition, and the targeted composition may not be obtained, so that the intended composition is obtained by heat treatment. The heat treatment conditions are not particularly limited, and are appropriately selected depending on the composition of the obtained thin film. The heat treatment conditions are not higher than the decomposition temperature of the target product, for example, within a temperature range of about 500 to 800 ° C. Can do. More specifically, for example, conditions for performing a heat treatment at 600 ° C. for 4 hours, conditions for performing a heat treatment at 600 ° C. for 4 hours, and further performing a heat treatment at 800 ° C. for 4 hours can be given.

A thin film containing a conductive material obtained by substituting a part of the perovskite oxide represented by La ₄ BaCu ₅ O ₁₃ obtained by the above method has low electrical resistivity and excellent TCR characteristics. It can be preferably used in applications such as electronic parts.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to the Example which concerns.
[Example 1]
In this embodiment, it will be described below so were prepared and evaluation of the conductive material is represented by _{La 4-X Pr X BaCu 5} O 13.

La ₂ O ₃ , BaCO ₃ , CuO and Pr ₂ O ₃ were used as starting materials. These starting materials were weighed and mixed so as to have the desired composition ratio, and calcined in air at 900 ° C. for 24 hours. After calcination, the obtained product was pulverized and mixed, and further molded into pellets, followed by firing in air at 1000 ° C. for 48 hours. In this example, the raw materials are weighed so that X = 0.1, 0.2, 0.4, and 0.6 in the formula represented by La _4-X Pr _X BaCu ₅ O ₁₃ , And prepared under the above conditions.

For comparison, La ₄ BaCu ₅ O ₁₃ , which is a base material (matrix) of the present invention, was also synthesized under the same conditions using La ₂ O ₃ , BaCO ₃ , and CuO as starting materials.

First, an X-ray diffraction pattern of La ₄ BaCu ₅ O ₁₃ produced as a reference sample is shown in FIG. FIG. 1 also shows an X-ray diffraction pattern calculated (simulated) from the structure of La ₄ BaCu ₅ O ₁₃ .

According to this, the measured X-ray diffraction pattern is almost the same as that calculated, and it can be seen that the target product La ₄ BaCu ₅ O ₁₃ is obtained under the above conditions.

Next, FIG. 2 shows an X-ray diffraction pattern of a sample of La _3.6 Pr _0.4 BaCu ₅ O ₁₃ , that is, X = 0.4 in the above formula. According to this, since it has diffraction lines at almost the same position as La ₄ BaCu ₅ O ₁₃ shown in FIG. 1 and other peaks were hardly seen, it is a single phase of a perovskite crystal structure. I understand that. Therefore, in this sample, it can be said that part of the La site is replaced by Pr. When the lattice constant was determined from the obtained X-ray diffraction pattern, it was decreased in both the a-axis and c-axis directions as compared to the non-substituted material (La ₄ BaCu ₅ O ₁₃ ). As a result, the volume V was also reduced.

Since the electrical characteristics of the obtained sample were evaluated, the results are shown in FIG. The measurement was performed by the four probe method and evaluated from about 0K to about 600K. For comparison, the material of the X = 0, i.e., also shown results of _La 4 BaCu ₅ O ₁₃ which is a base material that has not been Pr added.

Further, in order to confirm the effect of addition of Pr, FIGS. 4 to 6 show changes in parameters accompanying changes in the amount of Pr added from the data in FIG. FIG. 4 shows the amount of Pr added, that is, the change in electrical resistivity at 200 K accompanying the change in the amount of Pr added, with X in the formula represented by La _{4 -X} Pr _X BaCu ₅ O ₁₃ as the X axis. FIG. 5 similarly shows the change in electrical resistivity at 500 K with the Pr addition amount taken on the X-axis and the Pr addition amount change. FIG. 6 shows the change in the resistance temperature coefficient by taking the amount of Pr added to the X axis in the same manner.

As shown in FIGS. 3 to 5, by adding Pr, the electrical resistivity (specific resistance) of the present oxide represented by La _{4 -X} Pr _X BaCu ₅ O ₁₃ is in the temperature range from extremely low temperature to room temperature. It can be seen that there is a decrease of about 30% from the base material where X = 0.

  For example, the electrical resistivity at 500 K is about 1.6 mΩcm in the case of a parent material to which no Pr is added, whereas all of the samples examined this time are 1.2 mΩcm or less. Has decreased. Furthermore, depending on the amount added, a sample having a value of 1.0 mΩcm or less could be confirmed.

Next, as shown in FIG. 6, all of the samples examined this time have a resistance temperature coefficient of 2.5 × 10 ⁻³ mΩcm / K or less due to the addition of Pr, which is 3 than that of the parent material where X = 0. It was about 10% lower. Moreover, depending on the addition amount, it may be 2.0 × 10 ⁻³ mΩcm / K or less, and a significant decrease was confirmed. From this, it is also recognized that the addition of Pr has an effect of lowering the temperature coefficient of resistance, that is, improving the TCR characteristics.

As described above, it was confirmed that by substituting part of La ₄ BaCu ₅ O ₁₃ with Pr, the electrical resistivity was reduced and the TCR characteristics were improved.
[Example 2]
In this example, a conductive material represented by La ₄ BaCu _{5 -Y} Co _Y O ₁₃ was prepared and evaluated, and will be described below.

La ₂ O ₃ , BaCO ₃ , CuO and CoO were used as starting materials. These starting materials were weighed and mixed so as to have the desired composition ratio, and calcined in air at 900 ° C. for 24 hours. After calcination, the obtained product was pulverized and mixed, and further molded into pellets, followed by firing in air at 1000 ° C. for 48 hours. In this example, the composition of the sample is such that Y = 0.05, 0.1, 0.15, 0.25, 0.35 in the formula represented by La ₄ BaCu _{5 -Y} Co _Y O _13. The raw materials were weighed and mixed to prepare under the above conditions.

Further, as in the case of Example 1, for comparison, La ₂ Ba ₃ , BaCO ₃ , and CuO are used as starting materials, and La ₄ BaCu ₅ O that is a base material (matrix) of the present invention under the same conditions. ₁₃ was also synthesized.

FIG. 7 shows an X-ray diffraction pattern of a sample of La ₄ BaCu _4.75 Co _0.25 O ₁₃ , that is, Y = 0.25 in the above formula. According to this, since it has diffraction lines at almost the same position as La ₄ BaCu ₅ O ₁₃ shown in FIG. 1 and other peaks were hardly seen, it is a single phase of a perovskite crystal structure. I understand that. Therefore, in this sample, it is presumed that a part of the Cu site is replaced by Co. When the lattice constant was determined from the obtained X-ray diffraction pattern, the a-axis direction decreased and the c-axis direction increased compared to the non-substituted material (La ₄ BaCu ₅ O ₁₃ ). As a result, no change was seen in the volume V.

Since the electrical characteristics of the obtained sample were evaluated, the results are shown in FIG. As in the case of Example 1, measurement and evaluation were performed by the four-terminal method. In addition, for comparison, the results of a material with Y = 0, that is, La ₄ BaCu ₅ O ₁₃ which is a parent material not added with Pr are also shown.

In order to confirm the effect of Co addition, in FIG. 9, the horizontal axis represents the amount of Co added, that is, _{Y in the} formula represented by La ₄ BaCu _{5 —Y} Co _Y O ₁₃ is taken as the X axis, and 200 K in each composition. The electrical resistivity is shown. Similarly, the amount of Co added is taken on the X axis, FIG. 10 shows the electrical resistivity at 500 K in each composition, and FIG. 11 shows the resistance temperature coefficient calculated from the results of FIG.

  As shown in FIGS. 8 to 11, by adding Co, the electrical resistivity (specific resistance) is partially increased at extremely low temperatures compared to the parent material to which Co is not added. Also in this sample, the electrical resistivity was lower than that of the base material depending on the temperature range.

  For example, the electrical resistivity at 500 K is about 1.6 mΩcm for the parent material to which Co is not added, whereas the sample examined this time is approximately 1.2 mΩcm or less, confirming a significant decrease. did it. Furthermore, depending on the amount added, a sample having a value of 1.0 mΩcm or less could be confirmed.

Next, as shown in FIG. 11, all of the samples examined this time have a resistance temperature coefficient of 2.0 × 10 ⁻³ mΩcm / K or less, and further 1.5 × 10 ⁻³ mΩcm / K or less by adding Pr. As a result, a significant decrease was confirmed. From this, it is also recognized that the addition of Co has the effect of reducing the temperature dependence of the temperature coefficient of resistance, that is, the electrical resistivity.

As described above, it was confirmed that by substituting a part of La ₄ BaCu ₅ O ₁₃ with Co, the electrical resistivity was reduced and the TCR characteristics were improved.
[Example 3]
In this _embodiment, since _{La 4 BaCu 5-Y Co Y} O thin film containing a conductive material represented by ₁₃ Preparation and evaluation was carried out, will be described below.

  In this example, a thin film having a target composition was prepared by sputtering.

As a target, the number of pellets of cobalt oxide (Co ₃ O ₄ ) having a diameter of 11 mm on a sputter target having a diameter of 100 mm made of a perovskite oxide having a basic composition of La ₄ BaCu ₅ O ₁₃ according to the substitution amount. What was put was used. For example, when sputtering is performed using one cobalt oxide pellet, Co is calculated to replace 2.5% of the Cu site, and La ₄ BaCu _4.875 Co _0.125 O ₁₃ is obtained. In this example, the number of pellets was 1 (La ₄ BaCu _4.875 Co _0.125 O ₁₃ ) and 2 pellets (La ₄ BaCu _4.75 Co _0.25 O ₁₃ ). The cobalt oxide pellets were cut into four, and placed on a sputtering target made of La ₄ BaCu ₅ O ₁₃ so that they were substantially equidistant, and subjected to sputtering treatment.

  As conditions for the sputtering treatment, the substrate temperature was set to 350 ° C., and sputtering was performed by Ar gas discharge to form a film (film formation) so as to have a film thickness of about 500 nm.

  And after sputter vapor deposition, the heat processing for 4 hours was performed at 600 degreeC in air | atmosphere, and the target thin film sample was obtained by performing heat processing further at 800 degreeC in air | atmosphere after that.

First, in order to investigate the influence on the electrical conductivity (conductivity) of the thin film due to the difference in the substrate, as a reference example, a sample to which Co was not added, that is, a thin film of La ₄ BaCu ₅ O ₁₃ was used as a quartz substrate and SrTiO _3. Each film was formed on a single crystal substrate and evaluated. Conditions such as substrate temperature and heat treatment conditions were the same as described above. About the obtained sample, the temperature dependence of electrical conductivity (conductivity) was evaluated by the four-point probe method. The results are shown in FIG.

As can be seen from FIG. 12, when a quartz substrate is used, the electrical conductivity is low in a low temperature region near room temperature, and the change in electrical conductivity due to temperature is larger than when a SrTiO ₃ single crystal substrate is used. This is presumably because the orientation of the obtained thin film was poor.

On the other hand, when the SrTiO ₃ single crystal substrate was used, the crystal orientation was good and the change in electrical conductivity with temperature was small.

From the above results, in this example, a SrTiO ₃ single crystal substrate was used as the substrate.

FIG. 13 shows _four samples of La ₄ BaCu _{5 -Y} Co _Y O ₁₃ (Y = 0.125 or Y = 0.25) which were formed and heat-treated under the above-described conditions using a SrTiO ₃ single crystal substrate. The results of evaluating the temperature dependence of the electrical conductivity and Seebeck coefficient by the probe method are shown. In FIG. 13, the temperature dependence of the electrical conductivity of the La ₄ BaCu ₅ O ₁₃ film formed under the same conditions for comparison, that is, the sample not substituted with Co is also shown. Show.

  According to this, it can be seen that the electric conductivity is greatly improved by Co substitution. In addition, the change in electrical conductivity due to temperature change is small, and it can be seen that the measured temperature range has stable performance.

As described above, the conductive material obtained by substituting a part of the perovskite oxide represented by La ₄ BaCu ₅ O ₁₃ is the same as the bulk sample shown in Examples 1 and 2 in the thin film sample. It can be seen that the conductivity characteristics and the TCR characteristics are excellent. For this reason, it can be preferably used in applications such as electronic parts.

Japanese Patent Laid-Open No. 10-335109

Mat. Res. Bull. 20 (1985) 667-671 J. et al. Mater. Chem. 8 (1998) 2695-2700

Claims (9)

A conductive material having reduced electrical resistivity by replacing a part of the perovskite oxide represented by La ₄ BaCu ₅ O ₁₃ with Pr,
A conductive material represented by La _{4 -X} Pr _X BaCu ₅ O ₁₃ (0.05 ≦ X ≦ 0.60).   The conductive material according to claim 1, wherein an electrical resistivity at 500 K is 1.2 mΩcm or less. 3. The conductive material according to claim 1, wherein a temperature coefficient of resistance at 200 K to 500 K is 2.5 × 10 ⁻³ mΩcm / K or less. A conductive material having a reduced electrical resistivity by replacing a part of the perovskite oxide represented by La ₄ BaCu ₅ O ₁₃ with Co,
A conductive material represented by La ₄ BaCu _{5 -Y} Co _Y O ₁₃ (0.05 ≦ Y ≦ 0.35).   The conductive material according to claim 4, wherein an electrical resistivity at 500 K is 1.2 mΩcm or less. 6. The conductive material according to claim 4, wherein the temperature coefficient of resistance at 200 K to 500 K is 2.0 × 10 ⁻³ mΩ cm / K or less.   A resistor paste comprising the conductive material according to any one of claims 1 to 6.   A resistor comprising the conductive material according to claim 1.   A thin film comprising the conductive material according to claim 1.

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