Nanoparticle structure material and preparation method thereof

Abstract

The present invention provides a novel nanoparticle structure material having magneto-optical properties different from those of existing nanoparticle structure materials and a method for manufacturing the same. The nanoparticle structure material has a composition represented by L-M-F-O, wherein at least one element selected from the group consisting of Fe, Co and Ni is set to L, at least one element selected from the group consisting of Li, Be, Mg, Al, Si, Ca, Sr, Ba, Bi, and rare earth elements is set to M, fluorine is set to F, and oxygen is set to O. The nanoparticle structure material of the present invention is composed of a matrix and metal oxide nanoparticles, the matrix is ​​composed of a fluorine compound having a composition represented by M-F, and the metal oxide nanoparticles are dispersed in the matrix and have a composition represented by L-O.

Description

[Technical field]

[0001] The invention relates to a nano-particle structure material and a manufacturing method thereof. [Background Technology]

[0002] The applicant of the present application has proposed a magnetic thin film having a nano-grain structure in which nano-sized metal particles are dispersed in an insulator matrix (see Patent Document 1).

[0003] [Prior art literature]

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent No. 6619216 [Summary of the invention]

[0006] Problems to be solved by the invention

[0007] The object of the present invention is to provide a novel nano-particle structure material having magneto-optical properties different from those of existing nano-particle structure materials and a method for manufacturing the same.

[0008] Means for solving problems

[0009] The nanoparticle structure material of the present invention,

[0010] It is composed of a matrix and metal oxide nanoparticles, the matrix is ​​composed of a fluorine compound having a composition represented by MF, the metal oxide nanoparticles are dispersed in the matrix and have a composition represented by LO, and the nanoparticle structure material has a composition represented by LMFO, wherein at least one element selected from the group consisting of Fe, Co and Ni is set to L, at least one element selected from the group consisting of Li, Be, Mg, Al, Si, Ca, Sr, Ba, Bi, and rare earth elements is set to M, fluorine is set to F, and oxygen is set to O, the atomic ratio of L is included in the range of 0.03 to 0.50, the atomic ratio of M is included in the range of 0.03 to 0.30, the atomic ratio of F is included in the range of 0.06 to 0.65, and the atomic ratio of O is included in the range of 0.04 to 0.50.

[0011] The method for preparing the nanoparticle structure material of the present invention comprises the following steps:

[0012] The primary nanoparticle structure material is heat treated in an oxygen-containing atmosphere within a temperature range of 300 to 800° C. to obtain the nanoparticle structure material as a secondary nanoparticle structure material, wherein the primary nanoparticle structure material is composed of a matrix and metal nanoparticles, wherein the matrix has a composition represented by MF, and the metal nanoparticles are dispersed in the matrix and have a composition represented by L. [Drawings]

[0013] Figure 1 This is a schematic diagram illustrating a nanoparticle structure material as one embodiment of the present invention.

[0014] Figure 2 It is an explanatory diagram regarding the production conditions of the nano-particle structure material of the example.

[0015] Figure 3 It is an explanatory diagram of the XRD analysis results of each sample of the nano-particle structure material.

[0016] Figure 4 This is a diagram for explaining the wavelength dependence of the light transmittance of each sample of the nanoparticle structure material.

[0017] Figure 5 This is a diagram for explaining the wavelength dependence of the Faraday rotation angle of the nano-granular structure material of the example. [Specific implementation method]

[0018] (Composition of Nanoparticle Structure Materials)

[0019] Figure 1 The nanoparticle structure material (secondary nanoparticle structure material) as one embodiment of the present invention schematically shown in FIG is a nanoparticle structure material in which metal oxide nanoparticles 11 are dispersed in a matrix 12 composed of a fluorine compound. The nanoparticle structure material, for example, has a composition represented by LMFO when one or more elements selected from Fe, Co, and Ni are set as L, at least one or more elements selected from Li, Be, Mg, Al, Si, Ca, Sr, Ba, Bi, and rare earth elements are set as M, fluorine is set as F, and oxygen is set as O.

[0020] The atomic ratio of L is included in the range of 0.03 to 0.50, the atomic ratio of M is included in the range of 0.03 to 0.30, the atomic ratio of F is included in the range of 0.06 to 0.65, and the atomic ratio of O is included in the range of 0.04 to 0.50. The total atomic ratio of L and O is included in the range of 0.07 to 0.88. The total atomic ratio of M and F is included in the range of 0.12 to 0.93. The metal oxide nanoparticle 11 mainly has a composition represented by LO. The matrix 12 is mainly composed of a fluorine compound having a composition represented by MF. The total atomic ratio of L, M, F and O is 1.

[0021] The light transmittance of the nanoparticle structure material with respect to light in the wavelength range of 1000 to 1675 nm is within a range of 40% or more at an optical path length of 1 μm.

[0022] The Faraday rotation angle of the nanoparticle structure material with respect to light in the wavelength ranges of 500 to 680 nm and 720 to 1000 nm in the visible light region is within a range of 0.1 deg. / μm or more in absolute value.

[0023] The Faraday rotation angle of the nanoparticle structure material relative to light in the wavelength range of 1350 to 1650 nm, which is a wavelength band for optical communication, is within a range of 0.1 deg. / μm or more in absolute value.

[0024] (Method for producing nanoparticle structure material)

[0025] right Figure 1 The method for preparing a nanoparticle structure material having the structure shown in the figure is described. First, a primary nanoparticle structure material is prepared (step 1). The primary nanoparticle structure material is prepared, for example, by a sputtering method or an RF sputtering method (for example, refer to patent document 1). Sputtering is performed using a composite target in which a substrate of a fluorine compound is evenly arranged on a circular plate of a magnetic metal or its alloy, or using a target of a magnetic metal or its alloy and a target composed of a fluorine compound at the same time. During sputtering film formation, Ar gas is used. The film thickness of the nanoparticle structure material is controlled by adjusting the film formation time, for example, the film is formed to a thickness of about 0.3 to 5 μm. The substrate is indirectly water-cooled or maintained at an arbitrary temperature within a temperature range of 100 to 800°C. The sputtering pressure during film formation is controlled to be within a range of 1 to 60 mTorr. The sputtering power is controlled to be within a range of 50 to 350 W.

[0026] Thus, a primary nanoparticle structure material in which magnetic metal nanoparticles are dispersed in a matrix composed of a fluorine compound can be produced. The primary nanoparticle structure material has a composition represented by LMF, for example, when one or more elements selected from Fe, Co, and Ni are set as L, at least one or more elements selected from Li, Be, Mg, Al, Si, Ca, Sr, Ba, Bi, and rare earth elements are set as M, and fluorine is set as F. The atomic ratio of M is within the range of 0.01 to 0.40, the atomic ratio of F is within the range of 0.02 to 0.70, and the total atomic ratio of M and F is within the range of 0.03 to 0.97. The primary nanoparticle structure material has a nanoparticle structure in which metal nanoparticles are uniformly distributed in a matrix composed of a fluoride, the composition of the metal nanoparticles is represented by L, and the composition of the fluoride is represented by MF.

[0027] The particle size of the metal nanoparticles is, for example, in the range of 1 to 50 nm or 1 to 20 nm. The particle size distribution of the metal nanoparticles (and even the particle size distribution of the metal oxide nanoparticles 11 in the secondary nanoparticle structure material) can be adjusted by changing the film formation conditions and / or the film formation composition.

[0028] Then, the secondary nanoparticle structure material is produced by heat treating the primary nanoparticle structure material in a temperature range of 300 to 800° C. in an oxygen-containing atmosphere (step 2).

[0029] (Examples and Comparative Examples)

[0030] (Sample 1 (Comparative Example 1))

[0031] Select Fe and Co as L, select Ba as M, and make a product composed of Fe 44 Co 32 Ba 13 F 11 The primary nanoparticle structure material is represented as sample 1.

[0032] (Sample 2 (Comparative Example 2))

[0033] Sample 1 is in vacuum, such as Figure 2 As shown by the dotted line, the temperature was gradually raised from about 50°C to about 600°C over about 3 hours, and after heat treatment at about 600°C for about 1 hour, the temperature was gradually lowered to about 80°C over about 4 hours, thereby producing sample 2. The composition of sample 2 is Fe 44 Co 32 Ba 13 F 11 express.

[0034] (Sample 3 (Example))

[0035] In a mixed gas atmosphere of Ar gas and O2 gas (the partial pressure of O2 gas is about 1% of the mixed gas), Figure 2 Sample 1 was heat treated in the temperature variation shown by the middle dashed line, thereby producing Sample 3 as a composite composed of Fe 23 Co 17 8F6 46 Represents the secondary nanoparticle structure material. Figure 2 As indicated by the solid line in the middle, the pressure of the mixed gas of Ar gas and O 2 gas is controlled to be approximately 30 mTorr.

[0036] Figure 3 The upper part of the figure shows the XRD analysis results of sample 1 (primary nanoparticle structure material). Figure 3 The lower part of the figure shows the XRD analysis results of sample 3 (secondary nanoparticle structure material). Figure 3It can be seen that the peaks derived from Fe and Co constituting the metal nanoparticles present in Sample 1 do not exist in Sample 3, but instead there are peaks derived from CoFe2O4 constituting the metal oxide nanoparticles. This means that by heat-treating the primary nanoparticle structure material in an oxygen-containing atmosphere, the metal nanoparticles contained in the primary nanoparticle structure material are oxidized and become metal oxide (composite metal oxide) nanoparticles in the secondary nanoparticle structure material.

[0037] Depend on Figure 3 It can be seen that the height of the peak derived from BaF2 constituting the matrix existing in Sample 1 becomes lower in Sample 3. This means that by heat-treating the primary nanoparticle structure material in an oxygen-containing atmosphere, the matrix constituting the primary nanoparticle structure material undergoes a qualitative change and becomes the matrix in the secondary nanoparticle structure material.

[0038] Figure 4 The dotted line shows the wavelength dependence of the light transmittance (optical path length 1 μm) of sample 1, and the solid line shows the wavelength dependence of the light transmittance of sample 3. Figure 4 It can be seen that for light in the wavelength range of 1000~1675nm used for optical communication, the transmittance of sample 1 is 0.5~1.0% (optical path length 1μm), while the transmittance of sample 3 is 58~81% (optical path length 1μm), which is significantly higher than the transmittance of sample 1.

[0039] Figure 5 The Faraday rotation angle θ of the sample 3 when the applied magnetic field to the sample 3 is 10 kOe is shown. F The wavelength dependence of Figure 5 It can be seen that the Faraday rotation angle θ of sample 3 is F As the wavelength increases from λ=400nm, it shows a tendency to gradually increase, shows a maximum value of about 2.5deg / μm at λ=about 530nm, and then shows a tendency to gradually decrease, shows a tendency to gradually decrease after changing from a positive value to a negative value at λ=about 700nm, shows a tendency to gradually decrease, shows a minimum value of about -1.5deg / μm at λ=about 750-800nm, and then shows a tendency to gradually increase, shows a maximum value of about 0deg / μm at λ=about 1300nm, and then shows a tendency to gradually decrease, shows a minimum value of about -1.0deg / μm at λ=about 1480nm, and then shows a tendency to gradually increase, and shows a tendency to gradually increase after changing from a negative value to a positive value at λ=about 1650nm.

[0040] The absolute value of the Faraday rotation angle of the nanoparticle structure material is within the range of 0.1 deg / μm or more relative to light in the wavelength range of 500 to 680 and 720 to 1000 nm in the visible light region. In addition, the absolute value of the Faraday rotation angle of the nanoparticle structure material is within the range of 0.1 deg / μm or more relative to light in the wavelength range of 1350 to 1650 nm, which is the optical communication band.

[0041] Table 1 summarizes the heat treatment conditions of each of Samples 1 to 3, as well as the Faraday rotation angle and the light transmittance at a wavelength λ=1550 nm at an optical path length of 1 μm.

[0042] [Table 1]

[0043]

[0044] (use)

[0045] Magneto-optical materials with Faraday effect are often used in optical isolators. The nanoparticle structure material of the present invention is a thin film material with a thickness of submicron level, which has a large Faraday effect under a tiny size. By using this material, optical isolators can be miniaturized and integrated, and can be applied to optical integrated circuits, etc.

[0046] [Explanation of symbols]

[0047] 11: metal oxide nanoparticles; 12: matrix.

Claims

1. A nanoparticle structure material, which is composed of a matrix and metal oxide nanoparticles, wherein the matrix is ​​composed of a fluorine compound having a composition represented by MF, the metal oxide nanoparticles are dispersed in the matrix and have a composition represented by LO, and the nanoparticle structure material has a composition represented by LMFO, wherein: At least one element selected from the group consisting of Fe, Co and Ni is set to L, at least one element selected from the group consisting of Li, Be, Mg, Al, Si, Ca, Sr, Ba, Bi and rare earth elements is set to M, fluorine is set to F, and oxygen is set to O, the atomic ratio of L is within the range of 0.13 to 0.40, the atomic ratio of M is within the range of 0.08 to 0.20, the atomic ratio of F is within the range of 0.06 to 0.46, and the atomic ratio of O is within the range of 0.1 to 0.46, The absolute value of the Faraday rotation angle with respect to light in the wavelength band of 1550 nm is within a range of 0.13 deg / μm or more.

2. The nanoparticle structure material according to claim 1, wherein The absolute value of the Faraday rotation angle with respect to light in the wavelength band of 500 to 680 nm is within a range of 0.1 deg / μm or more.

3. The nanoparticle structure material according to claim 1, wherein The absolute value of the Faraday rotation angle with respect to light in the wavelength band of 720 to 1000 nm is within a range of 0.1 deg / μm or more.

4. The nanoparticle structure material according to claim 1, wherein The absolute value of the Faraday rotation angle with respect to light in the wavelength band of 1350 to 1650 nm is within a range of 0.1 deg / μm or more.

5. The nanoparticle structure material according to any one of claims 1 to 4, wherein The light transmittance with respect to light in the wavelength band of 1550 nm is within a range of 41% / μm or more.

6. The nanoparticle structure material according to claim 1, wherein The light transmittance with respect to light in the wavelength range of 1000 to 1650 nm is within a range of 40% / μm or more.

7. The nanoparticle structure material according to claim 1, wherein The atomic ratio of L is contained in the range of 0.17 to 0.40, the atomic ratio of M is contained in the range of 0.08 to 0.20, the atomic ratio of F is contained in the range of 0.06 to 0.23, and the atomic ratio of O is contained in the range of 0.36 to 0.

46.

8. A method for producing a nanoparticle structure material, comprising the following steps: The primary nanoparticle structure material is heat treated in an oxygen-containing atmosphere at a temperature range of 300 to 800° C., thereby obtaining the nanoparticle structure material according to any one of claims 1 to 7 as a secondary nanoparticle structure material, The primary nanoparticle structural material is composed of a matrix composed of a fluorine compound having a composition represented by MF and metal nanoparticles, the matrix being composed of a fluorine compound having a composition represented by MF, and the metal nanoparticles being dispersed in the matrix and having a composition represented by L.

9. The method for producing the nanoparticle structure material according to claim 8, comprising the following steps: In the first step, the temperature of the substrate is controlled to be a first temperature within a temperature range of 300 to 800° C., and the atmospheric pressure of the substrate is controlled to be 1.0×10 -4 Below Pa; as well as In the second step, a composite target of an insulating material and a metal or multiple separate targets are used to control the temperature of the substrate to a second temperature within the range of 300 to 800°C, the atmosphere of the substrate is adjusted to a non-oxidizing atmosphere, and the atmosphere pressure of the substrate is controlled within the range of 0.1 to 10 Pa, while forming a film of the primary nanoparticle structure material on the substrate, wherein the insulating material is composed of at least one element selected from Li, Be, Mg, Al, Si, Ca, Sr, Ba, Bi, rare earth elements and F, and the metal is composed of at least one element selected from Fe, Co and Ni.

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