JPS6176638A - Variable spectral reflectivity alloy and recording material - Google Patents

Abstract

PURPOSE:To provide a variable spectral reflectivity alloy which can maintain partially different spectral reflectivities at the same temp. by incorporating Sn and Al respectively at prescribed ratios into the alloy and consisting the balance of Cu as the essential component. CONSTITUTION:The alloy of this invention is subjected to a heating and cooling treatment in the solid phase state to have at least >=2 kinds of spectral reflectivities at the same temp. and can vary reversibly the spectral reflectivities. The spectral reflectivity varies with the state in which the high-temp. phase out of said phases is quickly cooled and the standard state without quick cooling. The spectral reflectivity is reversibly changed by the heating and quick cooling in the temp. region of the high-temp. phase and the heating and cooling in the temp. region of the low-temp. phase. The compsn. of this alloy contains 15-35wt% tin and 0.01-3.0wt% Al and consists of the balance Cu as the essential component. The alloy is usable particularly for media for information recording, displaying, sensing, etc. with which the change in the spectral reflectivity with a change in the crystal structure of the alloy by the light and heat energy applied thereto is utilized.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a novel alloy with variable spectral reflectance and a recording material, and in particular to a novel alloy with variable spectral reflectance and a recording material, and in particular, the spectral reflectance of the alloy changes as the crystal structure of the alloy changes due to the application of light and thermal energy. This invention relates to alloys that can be used for media such as information recording 1 display and sensors that utilize changes.

[Background of the invention]

In recent years, as information recording becomes more dense and digital, various information recording and reproducing methods are being developed. Especially for recording information using laser light energy.

The optical disc used for erasure and playback is made of industrial rare metal Nα.
80, 1983 (Optical Disks and Materials), it is possible to achieve higher recording density than magnetic disks, and is a promising method for information recording in the future. Among these, laser playback devices have been put into practical use as compact discs (CDs).

On the other hand, recordable methods can be broadly divided into two types: write-once type and rewritable type. The former allows writing only once and cannot be erased, while the latter allows repeated recording and erasing. In the write-once type recording method, a laser beam is used to destroy or shape the recording portion of the medium to create unevenness, and for reproduction, a change in the amount of light reflected due to the interference of the laser beam at the uneven portion is used for reproduction. For this recording medium, it is generally known that Te or its alloy is used to form irregularities by melting and sublimating Te. This type of medium has some problems such as toxicity. Magneto-optical materials are the mainstream for rewritable recording media. This method uses optical energy to invert and record the local magnetic anisotropy of the medium near the Curie point or the compensation point temperature, and the polarization plane of the polarized incident light at that part is caused by the magnetic Faraday effect and magnetic Kerr effect. The method of reproducing light with the amount of rotation of the plane of polarization is the most promising method for rewritable light, and active research and development is underway with the aim of putting it into practical use in the next few years. There is a big problem that there is no large material, and even if various measures such as multilayer film formation are taken, output levels such as S/N and C/N are low.

Other rewritable systems utilize reflectance changes due to reversible phase changes between amorphous and crystalline recording media. For example, National Technical
There is an alloy in which small amounts of Ge and Sn are added to TeOx, as described in Report Vol. 129 Nn 5 (1983).

However, this method has a major problem in that the crystallized portion of the amorphous phase is low, and the instability of the phase at room temperature affects the reliability of the disk.

On the other hand, as an alloy utilizing one color tone change, JP-A-57-1
There are 40845. This alloy is (12-15)wt%A
Q-(1-5) is an alloy consisting of wt%Ni-remaining Cu, which takes advantage of the fact that it reversibly changes from red to gold at the martensitic transformation temperature. Since martensitic transformation is a transformation that inevitably occurs as the temperature decreases, the color tone obtained when the temperature is maintained above the martensitic transformation temperature cannot be brought below the martensitic modulation temperature. Conversely, if a color tone obtained below the martensitic transformation temperature is raised above the martensitic transformation temperature, it will undergo transformation and change to a different tone. Therefore, the two hues that occur above and below the martensitic transformation are the same. It is not possible to obtain both temperature and temperature at the same time. Therefore, this principle cannot be applied as a recording material.

[Purpose of the invention]

An object of the present invention is to provide a variable spectral reflectance alloy and a recording material that can maintain partially different spectral reflectances at the same temperature.

[Summary of the invention]

(Summary of the Invention) The present invention has ff1 (Cu) as a main component, tin (Sn)1
6-35% by weight and weight aluminum (AQ) O, OL
The variable spectral reflectance alloy is characterized in that it consists of an alloy containing ~3.0% by weight.

That is, the present invention provides a first temperature higher than room temperature (
An alloy having different crystal structures at a temperature lower than the first temperature (high temperature) and at a temperature lower than the first temperature (low temperature), characterized in that the alloy has a crystal structure different from that obtained by non-quenching at the low temperature due to quenching from the high temperature. It is an alloy with variable spectral reflectance.

The alloy of the present invention has at least two types of spectral reflectance at the same temperature by heating and cooling treatment in a solid state, and the spectral reflectance can be changed reversibly. That is, the alloy according to the present invention has phases with different crystal structures in at least two temperature regions in the same phase state, and among these, the high-temperature phase is quenched and the low-temperature phase state is the standard state without quenching. The reflectance is different, and the spectral reflectance changes reversibly by heating and cooling in the high phase temperature region and heating and cooling in the low temperature phase region.

The addition of AQ is intended to improve acid water resistance.

That is, since the Cu-Sn alloy that does not contain AQ has poor oxidation resistance, it is oxidized by the heat treatment described below, making it difficult to differentiate the color tone changes. However, AQ is 0.
When it is contained in an amount of 01 to 3.0% by weight, the oxidation resistance is significantly improved and the color tone change becomes clearer.

Figure 1 schematically shows the change in crystal structure due to phase transformation of a Cu-Sn alloy.Using this diagram, information such as 2 characters, 2 figures, symbols, etc. for signals necessary for recording materials can be calculated. Explain the principle of recording and erasing information. In the alloy having the composition CI in FIG. 1, there are three phase states in the solid state.

That is, there are γ single phase, α+δ phase, and α+ε phase. The crystal structure is γ and α.

The single phase states of δ and ε are different, so it is natural that they are used alone, but their optical properties also change depending on their mixed phase. Spectral reflectance will be explained as a difference in optical properties due to a difference in crystal structure. T means the temperature at which what is recorded can be read, and it can be thought of as room temperature. In the equilibrium state in T-engine, ε-rich
Since it is an α+ε phase, the spectral reflectance of the alloy is close to ε. When this is heated to T4 and rapidly cooled, the γ phase is maintained at T1.

The spectral reflectance of the γ phase at T1 is different from that of the α+ε phase.

Therefore, both phases can be distinguished.

To describe general color characteristics, the γ phase at T1 when rapidly cooled after holding is golden yellow, and the α+β and α+δ phases are silvery white. That is, the alloy in the α+ε phase state is irradiated with a laser beam having a diameter of several μm, for example, to locally heat it to T4, and then the laser irradiation is stopped. The irradiated part is rapidly cooled, and at T1 becomes the γ phase of the laser irradiated part. The area not irradiated with laser is α1ε
Since the phase remains unchanged, the state in which the spectral reflectance of the laser irradiated part is different from the other part at T1 and the two can be distinguished corresponds to the recording state. On the other hand, the material in the γ phase state retained in the T after being rapidly cooled after heating is T.
When heated to a higher T, the γ phase changes to α+δ phase and T1
Even if the temperature is returned to , the α+δ phase remains. therefore,
As mentioned above, when laser light is irradiated to the part that has locally become γ phase by laser irradiation and heated to a temperature of T2, the γ phase changes to α+
Changes to δ phase. Even after the temperature is returned to T1, the α+δ phase state is maintained. In other words, this corresponds to erasure. Note that in order to change the phase to the α+δ phase, it is sufficient to heat it to a temperature higher than T1, but the upper limit temperature is the temperature at which the γ phase does not precipitate when maintained at a high temperature, Ta in Figure 1,
That is, it is the eutectoid temperature. The above process can be repeated and can be applied as a so-called rewritable recording medium.

Still other recording methods can be applied.

That is, a sample in the γ phase state at temperature T1 is used as the state before recording. For example, when this is irradiated with a laser beam having a diameter of several μm and heated to T2, the laser irradiated part changes to an α+δ phase. Even after cooling to a temperature of T□, the laser irradiated part remains α+δ.
This phase can be distinguished from the phase of the non-laser irradiated area because its spectral reflectance is different6, so it can be recorded. Erasing can be done by heating the entire surface of the sample to T2 and then cooling it.
This is because it changes into phases.

As described above, the present invention provides a material that can be recorded and erased by using an alloy that has different phases of at least 25a crystal structure in a solid state and maintains the phase in one temperature range in the other temperature range. It is.

According to the recording and erasing mechanism using light and thermal energy as described above, the composition of the alloy is limited as described above.

In the present invention, the γ phase, which is stable at high temperatures, is rapidly cooled and maintained at a temperature at which recording can be read.

Therefore, in order to effectively realize recording and erasing by heating and quenching, reducing the heat capacity of the recording medium increases its response speed. Therefore, it is effective to form a thin film by directly rapidly cooling and solidifying it into a foil or film form from the gas phase or liquid phase. PVD (vapor deposition, sputtering, etc.) is a method for forming thin films.

There are CVD methods, molten metal quenching methods in which molten metal is poured onto metal rolls rotating at high speed and rapidly solidified, methods in which fine powder is applied and fired, electroplating, chemical plating, and the like. The crystal grains of the foil or thin film are preferably as fine as possible in order to locally change the spectral reflectance and obtain a high electrical signal output. The above-mentioned method generally forms a foil or film in a rapidly cooled state, so the crystal grains are very fine, and it is very suitable as a method for producing a recording medium. Furthermore, from the viewpoint of reducing heat capacity, it is very effective to powder the metal or alloy of the recording medium. It is more effective to mix this with a binder and apply it to form a film. In the case of a film formed on a substrate as described above, it is also effective to divide the film into the minimum size of the recording unit by chemical etching or the like to reduce the heat capacity of each film.

By utilizing the reversible changes in spectral reflectance and color tone as described above, it can be applied not only to recording media such as optical disks and memories, but also to sensors such as display elements and temperature sensors.

(Alloy Composition) The alloy of the present invention has different crystal structures at high and low temperatures, and the rapidly cooled crystal structure must be formed by rapid cooling from a high temperature. Furthermore,
The phase formed by this rapid cooling must be able to change into a crystalline structure at a low temperature by heating at a predetermined temperature.

(Non-bulk and manufacturing method thereof) In order to obtain reflectance variability, the alloy of the present invention must be capable of forming an appropriately cooled phase by heating and rapidly cooling the material. In order to create and store information at high speed, it is desirable to use a non-bulk material with a high rapid heating and cooling effect and a small heat capacity. That is, it is desirable to be a non-bulk material having a volume that allows substantially only a desired area portion to be changed to a crystal structure different from a reference crystal structure throughout the depth by energy input to a desired minute area. Therefore, in order to produce high-density information in a desired minute area, non-bulk materials such as foils, films, thin wires, or powders with low heat capacity are desirable. The recording density is 0.01 to 0.2μ for producing information in a small area such as 20 megabits/a1 or more.
It is preferable to set the film thickness to m. Generally, intermetallic compounds are difficult to plastically work.

Therefore, it is effective to directly rapidly cool and solidify the material from the gas phase or liquid phase to form it into a predetermined shape as a method for producing foil, film, thin wire, or powder. These methods include a PVD method (vapor deposition, sputtering method, etc.), a CVD method, and a member having high thermal conductivity that rotates the molten metal at high speed. In particular, there are molten metal quenching methods in which molten metal is poured onto the circumferential surface of a metal roll and rapidly solidified, electroplating methods, chemical plating methods, and the like. When using a film or powder material, it is effective to form it directly on the substrate or to apply it and adhere it to the substrate. When applying, a binder that does not cause any reaction even when the powder is heated is preferred. In addition, to prevent oxidation of the material due to heating,
It is also effective to coat the surface of the material, the pancreas formed on the substrate, or the surface of the coating layer.

The foil or thin wire is preferably formed by the R8 hot water quenching method, and preferably has a thickness or diameter of 0.1 or less.

In particular, a thickness or diameter of 0.05 mm or less is preferable for producing foil or fine wire with a crystal grain size of 0.1 μl or less), l Powder is prepared by spraying molten metal with a gas or liquid refrigerant into water. Preferably, the formation is performed by a Gaia atomization method in which the material is poured and rapidly cooled. The particle size is preferably 0.1 μm or less, and ultrafine powder with a particle size of 1 μm or less is particularly preferable.

As mentioned above, the coating can be formed by vapor deposition, sputtering, CVD electroplating, chemical plating, etc.

In particular, sputtering is preferable to form a film with a thickness of 0.1 μl or less. Sputtering allows easy control of the target alloy composition.

(Structure) The alloy of the present invention must have a different crystal structure at high and low temperatures, and must have a composition of a supercooled phase in which the crystal structure at high temperature is maintained at low temperature by rapid cooling from high temperature. It has a regular lattice crystal structure, but
The supercooled phase is preferably an intermetallic compound having a Cs-CQ type or Do type regular lattice, for example. As the alloy of the present invention is capable of greatly changing optical properties, it is preferable that the alloy mainly forms this intermetallic compound, and a composition in which the entire alloy forms an intermetallic compound is particularly preferable. This intermetallic compound is called an electronic compound, and those having an alloy composition close to a 3/2 electron compound (average outer shell electron concentration e/a of 3/2) are particularly good.

In addition, the alloy of the present invention preferably has an alloy composition having eutectoid transformation, and the alloy can obtain a large difference in spectral reflectance by rapid cooling from high temperature and non-quenching.6 The alloy of the present invention is an alloy having ultrafine crystal grains. is preferable, especially the crystal grain size is 0.1
It is preferably less than μm.

That is, the crystal grains are preferably smaller than the wavelength of visible light, but may be smaller than the wavelength of semiconductor laser light.

(Characteristic) The variable spectral reflectance alloy and recording material of the present invention are as follows.

At least two types of spectral reflectance in the visible light region can be formed at the same temperature. That is, it is necessary that the spectral reflectance of a material having a crystal structure (Milft'1) formed by rapid cooling from a high temperature is different from that of a material having a crystal structure (texture) formed by non-quenching.

Further, the difference in spectral reflectance obtained by quenching and non-quenching is preferably 5% or more, particularly preferably 10% or more. If the difference in spectral reflectance is large, it is easy to visually identify the color, and this has a significant effect in various uses described later.

As a light source for spectrally reflecting, electromagnetic waves other than visible light can be used, and infrared rays, ultraviolet rays, etc. can also be used.

Other properties of the alloy of the present invention include electrical resistivity, optical refractive index, optical polarization rate, optical transmittance, etc., which can be changed reversibly in the same way as spectral reflectance.
It can be used as a regeneration and detection means for sensors, etc.

Since the spectral reflectance is related to the surface roughness of the alloy, it is preferable that at least the intended portion has a mirror surface so as to have 10% or more in the visible light region as described above.

(Applications) The alloy of the present invention has a spectral reflectance of electromagnetic waves due to a partial or total change in crystal structure due to heating and rapid cooling.

Physical or electrical properties such as electrical resistivity, refractive index, polarization index, transmittance, etc. can be changed, and changes in these properties can be utilized to use for elements such as recording, display, and sensors.

As a means of recording information, etc., electrical energy in the form of voltage and current, electromagnetic waves (visible light, 11 radiation heat).

Infrared rays, ultraviolet rays, photographic flash lamp light, electron beams,
A proton beam, a laser beam such as an argon laser, a semiconductor laser, heat, etc.) can be used, and it is particularly preferable to utilize the change in spectral reflectance caused by the irradiation in the recording medium of an optical disk. Optical disks include digital audio disks (DAD or compact disks), video disks, memory disks, and the like, and can be used for these. By using the alloy of the present invention in the recording medium of an optical disk, a read-only type and an additional recording type can be created.

It can be used in any rewritable disk device, and is particularly effective in rewritable disk devices.

An example of the principle of recording and reproduction when the alloy of the present invention is used in a recording medium of an optical disk is as follows.

First, the recording medium is locally heated and then rapidly cooled to maintain the crystal structure in the high temperature region in the low temperature region to record predetermined information, or the high temperature phase is locally heated as a base. recorded by locally low-temperature phases during high-temperature heating,
Information can be reproduced by irradiating the recorded portion with light and detecting the difference in optical characteristics between the heated portion and the non-heated portion. Furthermore, the recorded information can be erased by heating the portion recorded as information at a temperature lower or higher than the heating temperature at the time of recording. The light is preferably a laser beam, particularly a short wavelength laser. Since the reflectance between the heated portion and the non-heated portion of the present invention is greatest at a wavelength around 500 nm or 800 nm, it is preferable to use a laser beam having such a wavelength for reproduction. It is preferable that the same laser source be used for recording and reproducing, and for erasing, a different laser beam having a lower energy density than that for recording is irradiated.

In addition, a disk using the alloy of the present invention as a recording medium has a great advantage in that it can be visually determined whether information is recorded or not.

As a display, it is possible to partially change the spectral reflectance of visible light, so it is possible to record characters, figures, symbols, etc. without using paint, and these displays can be visually identified. . Furthermore, this information can be erased, and in addition to being used repeatedly by recording and erasing, it is also possible to store it permanently. Examples of its applications include clock faces and accessories.

As a sensor, there is a temperature sensor that utilizes changes in spectral reflectance, especially in visible light. Approximate temperature detection can be made by holding a sensor using the alloy of the present invention, whose temperature at which it changes to a high temperature phase is known in advance, in the temperature range to be measured, and maintaining the appropriate cool phase by cooling it appropriately.

(Production method) The present invention provides a first temperature higher than room temperature in a solid state and a first temperature higher than room temperature in a solid state.
A part of the surface of the alloy having the chemical composition described above, which has a crystal structure different from that at the second temperature lower than the temperature, is rapidly cooled from the first temperature to form a crystal structure different from the crystal structure at the second temperature. and forming a region having a crystal structure formed by the rapid cooling and forming a different spectral reflectance between the region having the crystal structure formed by the rapid cooling and the region having the crystal structure at the second temperature. It is in the manufacturing method of the alloy.

Furthermore, the present invention provides a method for applying the first temperature to the entire surface of the alloy having the chemical composition described above, which has a different crystal structure at a first temperature higher than room temperature and a second temperature lower than the first temperature in a solid state. to form a crystal structure different from the crystal structure at the second temperature, and then heat a portion of the alloy surface to the second temperature to form a region having the crystal structure at the second temperature. and forming different spectral reflectances in the region having the crystal structure formed by the rapid cooling and the region having the crystal structure at the second temperature. be.

The cooling rate from the first temperature is 10”°C/second or more.

More preferably, it is 10''C/sec or more.

[Embodiments of the invention]

(Example 1) A ribbon-shaped foil with a thickness of approximately 40 μm was produced by a so-called liquid quenching method, in which a Cu-20wt%Sn-1wt%AQ alloy is molten and the molten metal is poured onto the outer periphery of a roll rotating at high speed. was created.

The ribbon was golden yellow at room temperature. 50 pieces of this ribbon
When heated at 0° C. for 2 min and cooled in air, the color changed to silvery white. Further, when this ribbon was heated to 650'C2ml and cooled with water, its color tone changed to golden yellow. When these color tone changes are organized in terms of the relationship between heating time and temperature, the results are shown in FIG. That is, the color is intermediate between golden yellow and silvery white at 300 to 380'C, silvery white at 400 to 550'C, and golden yellow at 600°C or higher. This hardly changes depending on the heating time. 600 pieces of foil that became silvery white in this way
When heated above ℃, it becomes golden yellow, and when the golden foil is heated below 550 ℃, it returns to silvery white.

A reversible tone memory effect thus occurs between these two colors. The above color tone change had a similar tendency in all cases in the composition range of the present invention other than the above-mentioned alloys. FIG. 3 shows the results of measuring the spectral reflectance of both of these. In the wavelength range except around 630 nm, each exhibits a unique reflectance change. It was possible to separate the la. From now on, these 2
Even after repeated heating and rapid cooling, this difference hardly changed, confirming the reproducibility of the reversible change.

(Example 2) A 50 nm thick alloy thin film having the same composition as in Example 1 was prepared on a glass substrate by sputter deposition, and AR, 0, or 5in2 was coated thereon as a protective film to a thickness of 50 nm by sputter deposition. . The produced film exhibited a golden color. Next, this film was heated and air cooled at 550° C. for 2 minutes, and as a result, the color tone changed to silvery white.

This spectral reflectance was almost the same as the result shown in FIG. A spot diameter of approximately 2 μm was applied to a sample whose entire surface was silver-white.
A semiconductor laser was scanned with an output of 30 mW or less. Observation of the laser irradiated area at room temperature revealed a silvery white base with a width of approximately 2μ.
I found that I was able to draw a golden line of m. That is,
It was confirmed that the color could be changed by local heating with laser light, and that laser irradiation could be recorded by the color change. Next, when the laser beam is irradiated onto the discolored area by lowering the laser output or slightly shifting the focus of the laser beam from the film surface, the line area that has changed to golden yellow can be reversibly changed to the silvery white color of the base. It changed to In other words, it was confirmed that what was recorded in golden color could be erased. It was also confirmed that this reversible change is possible even if it is repeated thereafter.

It was confirmed that the above results could also be obtained using an Ar laser.6 (Example 3) A semiconductor laser (output 20 mW) was scanned on a sample prepared in the same manner as in Example 2, that is, a sample whose entire surface was golden at room temperature. I let it happen. The laser scanning part turned silvery white at room temperature and could be distinguished from the color of the base.

In other words, the laser recording was completed6, and then the entire record was recorded5.
When heated to 50℃ for 2wins, the whole color changes to silvery white,
I was able to erase the recorded part.

The above results were also achieved using an Ar laser6 (Example 4) Similar to Example 1, Cu-27wt%Sn-1wt%A
Q alloy and Cu-30wt%5n-1%AQ alloy were manufactured and their 1-spectral reflectances were measured.

The results are shown in FIGS. 4 and 5, respectively.

〔Effect of the invention〕

The present invention is a recording material that can be recorded and erased based on a crystal-crystal phase change using light or thermal energy, and has
The output level is high and stable.

[Brief explanation of drawings]

Figure 1 is a binary alloy phase diagram schematically showing changes in crystal structure due to phase transformation of Cu-5n alloy, and Figure 2 is C
Diagrams showing the color tone changes of the u-208n-I A 11 alloy as a function of temperature.
-27'S n -I A Q and Cu-30Sn-I
It is a diagram showing the spectral reflectance of AQ alloy foil.

Claims (1)

[Scope of Claims] 1. An alloy with variable spectral reflectance, characterized in that it consists of an alloy containing copper as a main component, 16 to 35% by weight of tin, and 0.01 to 3.0% by weight of aluminum. 2. A part of the alloy surface having a different crystal structure at a first temperature higher than room temperature and a second temperature lower than the first temperature in the solid state is formed by rapid cooling from the first temperature. having a crystal structure different from the crystal structure at the second temperature,
2. The variable spectral reflectance alloy according to claim 1, wherein the other alloy has a crystal structure at the second temperature and has a spectral reflectance different from that of the rapidly cooled crystal structure. 3. The variable spectral reflectance alloy according to claim 1 or 2, wherein the alloy contains an intermetallic compound. 4. The variable spectral reflectance alloy according to any one of claims 1 to 3, wherein the first temperature is higher than the solid phase transformation point. 5. A patent claim in which the difference between the spectral reflectance of a product having a crystal structure formed by the rapid cooling and the spectral reflectance of a product having a crystal structure at the low temperature formed by non-quenching is 5% or more. The variable spectral reflectance alloy according to any one of the ranges 1 to 4. 6. The spectral reflectance of the alloy is at a wavelength of 400 to 1000 nm.
10% or more of the variable spectral reflectance alloy according to any one of claims 1 to 5. 7. Claim 1, wherein the alloy is a non-bulk material.
The variable spectral reflectance alloy according to any one of items 6 to 6. 8. The variable spectral reflectance alloy according to any one of claims 1 to 7, wherein the alloy has a crystal grain size of 0.1 μm or less. 9. The variable spectral reflectance alloy according to any one of claims 1 to 8, wherein the alloy is any one of a thin film, foil, strip, powder, and thin wire. 10. A recording material comprising an alloy containing copper as a main component, 16 to 35% by weight of tin, and 0.01 to 3.0% by weight of aluminum. 11. An alloy having different crystal structures in a solid state at a first temperature higher than room temperature and a second temperature lower than the first temperature, wherein at least a part of the alloy surface is at the first temperature. 11. The recording material according to claim 10, having an alloy composition that forms a crystal structure different from the crystal structure at the second temperature when quenched from the recording material. 12. The recording material according to claim 10 or 11, which is a foil or thin wire formed by pouring the molten metal of the alloy onto the circumferential surface of a rotating roll made of a highly thermally conductive member. 13. Claim 10 or 11, which is a thin film formed by depositing the alloy by vapor deposition or sputtering.
Recording materials listed in section. 14. The recording material according to claim 10 or 11, which is a powder obtained by spraying the molten metal of the alloy using a liquid or gas cooling medium.