JPS6137945A - Amorphous magnetism actuating material - Google Patents

Abstract

PURPOSE:To develop a magnetism actuating material having superior magnetism actuating property utilizing both spin grass property and large magnetic moment, by forming amorphous state alloy by melting or spattering method with specified materials and rare earth elements. CONSTITUTION:Amorphous alloy contg. >=1 kind among Eu, Gd, Tb, Dy, Ho Er, Tm having larger magnetic moment in rare earth elements, 1 kind or >=2 kinds among Al, Ga, Ni, Cu, Ag, Au, Ru, Rh, Pd, Pt, Fe, Co or further or >=2 kinds among the other rare earth elements such as La, Y, Sm, Ce, Nd, or 1 or >=2 kinds of Si, B, C is manufactured by melting method of ribbon method, anvil method or spattering method. The alloy compsn. is adjusted so that desired magnetic transition point is possessed over high to low temp. range, and magnetism actuating amorphous material having superior magnetism actuating property over wide actuating temp. range is manufactured by heat insulating degaussing under weak electric field.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a magnetically actuated material made of an amorphous alloy, and more specifically, the present invention relates to a magnetically actuated material made of an amorphous alloy, and more specifically, a magnetically actuated material made of an amorphous alloy. The present invention relates to a rare earth metal-containing amorphous magnetically actuated material having excellent magnetically actuated properties (eg, magnetic refrigeration or cooling).

(Prior Art) Conventionally, as a magnetically actuating material, for example, Dy2Ti20
7, DyPO4, Gd(OH),, Gd2 (S O,
)・8H20 and other oxides or oxygen-containing compounds are considered as magnetic refrigeration materials, and are expected to be used for ultra-low temperature refrigeration near the helium liquefaction temperature.

However, these compounds contain (1) an element responsible for magnetism (D
y, Gd, etc.), the content per molecule is small.
(2) Their Curie temperature to Neel temperature is low, about 10 T (K) at most, so it is impossible to freeze them from high temperatures such as room temperature. (3) These compounds have low magnetic refrigeration efficiency. It has a Curi temperature to a Neel temperature,
Only simple refrigeration around that temperature is relatively efficient and can only be expected to operate in a narrow range. (4) Since these substances are compounds, heat conduction is low, reducing refrigeration efficiency and refrigeration output. (5) For magnetic operation,
It has various limitations and drawbacks, such as requiring a strong magnetic field of several Tesla to 0 Tesla, and magnetic operation is only possible with the advent of superconducting magnets, which have been developed in recent years.

(Problems to be solved by the invention) The present invention eliminates the limitations and drawbacks of the prior art described above, and enables extremely highly efficient magnetic operation by adiabatic demagnetization under a weak magnetic field using a normal electromagnet. )I
Our aim is to provide new and original magnetically actuated materials that can be applied to a wide range of fields, from ultra-large plants such as power generation, nuclear fusion, and energy storage to linear motors and computer peripherals. That is.

(Structure of the Invention) In order to achieve the above object, the present inventor first conducted various analyzes and studies on various factors that cause the drawbacks of conventional magnetically actuating materials such as oxides.

As a result, the operating temperature was set to an ultra-low temperature near the helium liquefaction temperature to suit magnetic operation purposes such as ultra-low temperature refrigeration.
In view of the situation where it was necessary to take the form of oxides or oxygen-containing compounds in order to have magnetic transition temperatures such as the Curie temperature or the Neel temperature in this ultra-low temperature range, it is difficult to take the form of such compounds under these constraints. It was discovered that the magnetic transition must be used under severe conditions, and that its properties as a magnetically active material cannot be utilized efficiently.

Therefore, the inventor of the present invention came up with the idea of fundamentally reconsidering the use of its properties as a magnetically active substance, and made an earnest effort to elucidate the basic principle of magnetically active material.

As a result, as shown in Figure 1, the magnetic operation depends on the relationship between the amount of change in magnetic entropy ΔSm due to the external magnetic field and its temperature dependence, and this 68 m is near the magnetic transition temperature such as the Curie temperature or the Neel temperature. They focused their attention on the point where the maximum value is , and discovered that by utilizing the spin glass properties of an amorphous alloy and instead widening its magnetic transition point, it is possible to widen the magnetic operating temperature range. In addition, taking advantage of the fact that ΔSm depends on the magnetic moment of a substance, and by focusing on amorphous alloys and incorporating rare earth metals, we have expanded the magnetic operating temperature range and increased the size of 68 m. We have obtained the knowledge that both can be satisfied.

The amorphous alloy containing these rare earth metals is
It has a unique magnetization temperature dependence depending on the strength of the external magnetic field,
In particular, as shown in Figure 2, under a weak magnetic field, the spins of atoms tend to align and exhibit a metastable state (A), but under a demagnetized state or a far east magnetic field, the spins become disjointed as if they were paramagnetic. We discovered the use of the point that manifests glassiness (B), and as a result, the magnetic operation of rare earth metal-containing amorphous alloys is contrary to the application of a strong magnetic field in conventional magnetically actuated materials, and before use, when a weak magnetic field is applied = 4 uniformly. We have now discovered that this is possible, and have hereby completed the present invention.

That is, the gist of the present invention is as follows: (1) An amorphous alloy containing a rare earth metal having a large magnetic moment and capable of exhibiting spin glass properties, the composition of which is heated at high temperatures. It is adjusted to have a desired magnetic transition point ranging from low temperature to low temperature, and is configured to provide excellent magnetic operability over a wide operating temperature range by adiabatic demagnetization under a weak magnetic field using an ordinary electromagnet. (2) It is a combination of an amorphous alloy containing a rare earth metal having a large magnetic moment and capable of exhibiting spin glass properties, the composition of which is: It is adjusted to continuously have different magnetic transition points from high to low temperatures, and by adiabatic demagnetization under a weak magnetic field using an ordinary electromagnet, it has excellent magnetic operability over a wide operating temperature range. This is an amorphous magnetically active material characterized by being configured to provide the following effects.

The present invention will be explained in detail below.

Figure 1 shows the amount of change Δ in magnetic entropy due to the external magnetic field when a magnetically active substance is placed in an external magnetic field H and adiabatically demagnetized.
FIG. 2 is an explanatory diagram showing the temperature dependence of Sm, in which (A) is the case of the amorphous alloy according to the present invention, and (B) is the case of the conventional oxide.

As shown in Figure (B), with conventional oxides, efficient magnetic refrigeration can only be expected at one temperature: the sharp Curie temperature Tc or the Neel temperature Tn (usually near the helium liquefaction temperature). , in the present invention, efficient magnetic operation is possible in the region of the magnetic transition point Tm distributed over a wide range, and the 48 m can be expressed, for example, by a linear equation.

ΔSm=RQog(2J+1)...(1) Here, R: Constant angular momentum of the JAM child In the same figure (A), since it is a spin glass, the spins are easily aligned even in a relatively weak magnetic field below Tm. Therefore, it is possible to obtain 48 m, which is larger than other temperature ranges.

In this respect, with conventional oxides, as shown in the same figure (B),
The operating temperature was T' lower than the Curie temperature Tc or the Neel temperature Tn, but even below Tc or Tn, the spins are not in a completely parallel state due to thermal disturbance, and the spins are brought closer to a parallel arrangement. This is impossible with a magnetic field using an ordinary electromagnet, and requires a strong external magnetic field using a superconducting magnet, such as several Teslas or 10 Tesla. Furthermore, the obtained value of 48m was only a small value because the aim was to operate near the helium liquefaction temperature and the operation was performed at a temperature considerably lower than Tc or Tn.

In the present invention, an amorphous alloy is used in order to widen the operating temperature range where this 48 m has a large value, and as mentioned above, the size of 48 m is the magnetic moment ()-M( Based on the knowledge that the thickness of μB) is proportional to the width of the magnetic field, an amorphous alloy containing a rare earth metal is used as the magnetically actuating substance.

The magnetic moment M can be expressed by the following formula % formula % (2) Here, the relationship between gnisbin S and angular momentum, μB: Bohr magneton, and the actually measured magnetic moments of rare earth metals are shown in Table 1. It's tori.

As shown in Table 1, the magnetic moments of the various elements E u '' T m are large, so it is preferable to include them.

The amorphous alloy containing rare earth metals can be manufactured by the well-known melting method (ribbon method, anvil method) or sputtering method, and the component combinations are, for example, as listed below in the manufacturing process above. It's tori.

[A] Example of component combination by melting method: (1) Gd and C, AI, Ga, Ni, Cu, Ag
, Au, Ru, Rh, Pd, Pt, Fe, C
(2) Al and Gd, Dy, Tb, Pr,
Alloy with one or more of Ho, Er, Eu (3) Nj and Gd, Dy, Tb, Pr, Ho,
Alloy with one or more of Er, Eu (4) Au and Gd, Dy, Tb, Pr,
Alloy (5) with one or more of Ho, Er, and Eu (2) to (4), La, Y, Sm,
Alloy (6) in which one or more of Ce and Nd is added Alloy (6) in which one or more of Si, B, and C is added to the alloys of (2) to (4) [B ] Component combination on salmon by sputtering method (]) Gd, Cu, AI, Mg, Tj-1V, Cr, Nb.

One of Ge, Si, Au, Fe, Co, Nj, Mn
Species or alloys with two or more species (2) Ag and Gd, Dy, Tb, Pr, H
(3) Alloy of Au with one or more of the following: o, Er, Eu, Gd, Dy, Tb, Pr,
Alloy with one or more of Ho, Er, Eu (4) Cu and Gd, Dy, Tb, Pr, H
(5) Alloy of Nj and Gd, Dy, Tb, Pr
, Ho, Er, and Eu, and magnetic transition point T of an amorphous alloy containing rare earth metals.
m has composition dependence, examples of which are shown in Figures 3 to 9.
As shown in the figure. As shown in these examples, in the present invention,
By using various elements in a ternary or quaternary alloy system, the magnetic transition point Tm can cover most of the temperature range as the magnetic operating temperature. Therefore, it is possible to incorporate a plurality of amorphous alloys with different compositions into one unit, and in this case, by continuously changing the composition, the magnetic transition point Tm can also be continuously changed, as shown in Fig. 1 (A).
It is possible to make the peaks in the temperature dependence curve of 68 m as shown in Fig. 2 continuously line up.

Furthermore, the present invention utilizes the spin glass properties of an amorphous alloy containing rare earth metals due to adiabatic demagnetization under a weak magnetic field.

For example, to explain using the magnetization temperature dependence shown in FIG. 2, the external magnetic field H is H1=10000e, H2=500
When a weak external magnetic field is applied such as 0e, H, = 1500e, H4 = 1000e, and then adiabatic demagnetization is performed, the spins are aligned like ferromagnetism near circle A in the figure, although they are not completely parallel (A ). On the other hand, near circle B in the same figure,
In an extremely weak external magnetic field such as H5=300e or in a demagnetized state, the spins aligned in parallel become disjointed as if they were paramagnetic (B), exhibiting spin glass properties.

By utilizing this spin glass property, amorphous magnetically active materials do not require a strong magnetic field of several Teslas or 10 Teslas, which was required for conventional oxides by -11 As such, spins can be easily aligned like ferromagnetic materials in an extremely weak magnetic field.

(Example) Gd55A16o amorphous alloy ribbons were produced by the melting method, and an external magnetic field of 50.100.500.10000e was applied to each ribbon, and the temperature dependence curve of magnetization was examined. Got the results. So 10
When 000e was applied and demagnetization was repeated 50 times, magnetic cooling from 30K to IOK became possible.

Same <Gd55A1. ,,,Gd6. A ribbon of A1.5 amorphous alloy was prepared, and the temperature dependence of its magnetization was measured at 30, 100, 150, 500, and 10,000 e, respectively. The results are shown in FIGS. 11 and 12.

As the concentration of Gd increases, the magnetic transition point increases, so Gd4. AI6. It is possible to freeze from a higher temperature than in the case of ad4. A16. Since the magnetization value is also larger than that of the above, it is possible to further improve the efficiency of refrigeration.

(Effects of the Invention) As is clear from the detailed description above, the present invention provides an amorphous alloy containing rare earth metals that has a large magnetic moment and can exhibit spin glass properties, and which can be adiabaticly demagnetized under a weak magnetic field. Because it is magnetically operated,
(1) Since it is an amorphous alloy containing rare earth metals, its composition can be easily selected arbitrarily, and the magnetic transition point can also be set arbitrarily.For example, when incorporating into one unit as a refrigeration work material, the composition can be changed continuously (2) The type and amount of the magnetic element can be arbitrarily selected from a wide variety of types. (3) Because it is a metal, it has high thermal conductivity.For example, in the case of magnetic refrigeration, the refrigeration cycle can be made faster, and the refrigeration effect appears immediately.(4) An extremely weak magnetic field is required to exhibit the properties of spin glass. (5) Since it is an amorphous alloy containing rare earth metals, it has excellent mechanical properties, is easy to handle, and is resistant to impact and cyclic motion. , it has a very remarkable effect, so it can be expected to be applied to all kinds of fields including the large-scale plants mentioned above.

[Brief explanation of the drawing]

Figures 1 (A) and (B) are explanatory diagrams showing the temperature dependence of the amount of change in magnetic entropy ΔSm due to an external magnetic field, and Figure 2 is an explanatory diagram showing the magnetization temperature dependence. and (B) are diagrams showing the arrangement of spins, Figures 3 to 9.
Each figure shows the composition dependence of the magnetic transition point Tm, and each of FIGS. 10 to 12 shows the temperature dependence of magnetization due to different external magnetic fields. Patent applicant Takashi Nakamura, Patent attorney representing the New Technology Development Corporation Figure 3 Figure 4 Figure 5 N (%) Figure 6 Cu (10) Figure 7 Figure 8 Figure 9 X (%) Figure 10

Claims (1)

[Claims] 1. An amorphous alloy containing a rare earth metal that has a large magnetic moment and can exhibit spin glass properties, the composition of which is adjusted to have a desired magnetic transition point ranging from high to low temperatures. 1. An amorphous magnetically actuated material, characterized in that the amorphous magnetically actuated material is configured to provide excellent magnetic actuation over a wide operating temperature range by adiabatic demagnetization under a weak magnetic field using an ordinary electromagnet. 2. A combination of amorphous alloys containing rare earth metals that have a large magnetic moment and can exhibit spin glass properties, each of which has a continuous magnetic transition point that varies from high to low temperatures. An amorphous magnetically active material, characterized in that it is adjusted to provide excellent magnetic actuation over a wide operating temperature range by adiabatic demagnetization under a weak magnetic field using an ordinary electromagnet.