JPS6057133B2 - Thermomagnetic transfer recording method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for thermally transferring a recording pattern of a magnetic recording medium that has already been magnetically recorded to a metal magnetic thin film layer having a magneto-optic effect, and in particular, a method for thermally transferring a recording pattern on a magnetic recording medium, and in particular a method for thermally transferring a recording pattern and utilizing a magneto-optic effect while performing thermal transfer. The present invention relates to a thermomagnetic transfer recording method that allows monitoring of transferred information.

Magnetic transfer generally means transferring and recording a recording pattern of a magnetic recording medium, such as a magnetic tape or a magnetic card, which has already been magnetically recorded, by bringing it into close contact with an unrecorded magnetic recording medium.

In this case, the magnetic recording medium on which transfer is recorded is called a transfer recording medium, and this transfer recording medium is made of Fe.
-Ni-Co alloy thin film, MnBi thin film or GdFe
, Ti), Fe, DyFe, and other amorphous thin films are known. When these metal magnetic thin film layers are used as a transfer recording medium, there is an advantage that the transferred recording pattern can be observed optically and non-destructively due to the magneto-optic effect.

In particular, a metal magnetic thin film that has an axis of easy magnetization perpendicular to the film surface and has a small coercive force Hc, such as a G (3Fe amorphous thin film), can be easily placed on a magnetic tape or the like so that its magnetic surface is in contact with it. It has the advantage of being transferred and recorded. Figures 1a and 1b show an example of a magnetic card recording pattern transferred to an amorphous thin film under α in this way and observed with a polarizing microscope, and a is a musical pattern. , are for the test pattern. By the way, when performing magnetic transfer, transfer can be promoted by applying a bias magnetic field or heat from the outside.

For example, in the transfer shown in Figure 1a and b, only the portion where the magnetic field Hi generated from the magnetic card has a value larger than the coercive force Hc of the GdFe amorphous thin film is transferred, and a weaker magnetic field is generated. The part of the Gd
By setting the effective magnetic field exerted on the Fe amorphous thin film to be H1+Hb, as long as Hi+Hb''>Hc is satisfied, that part will be transferred even if Hi<Hc. This is called transfer in a magnetic field. .on the other hand,
By increasing the temperature of the transfer recording medium from room temperature Tr to TO during transfer, the coercive force of the transfer recording medium changes from coercive force Hc(Tr) at room temperature to coercive force Hc(TO) at high temperature.
), so a portion where Hi<Hc(Tr) at room temperature can become Hi>Hc(TO) at high temperature, which can be utilized to promote transfer. This is called thermomagnetic transfer. As a transfer recording medium that can utilize thermomagnetic transfer, that is, a thermomagnetic transfer recording medium, one whose coercive force Hc changes greatly with temperature is suitable, and metal magnetic thin films are generally suitable for this purpose, but among them, GbFe, T
l) Thermomagnetic recording media including amorphous thin films such as Fe and DyFe are particularly suitable. A conventional method of such thermomagnetic transfer is specifically shown in FIG. In the figure, 1 is a metal magnetic thin film, 2 is a heat generation source such as a hot ray lamp or flash lamp, 3 is a substrate such as glass, and 4 is a magnetic recording device such as a magnetic tape or magnetic card having a magnetic coating film 5 on a base 6. It is a medium. Then, the already recorded magnetic recording medium 4
The metal magnetic thin film 1 is brought into close contact with the metal magnetic thin film 1, and heat is applied to the metal magnetic thin film 1 by a heat generating source 2 through a substrate 3 placed on the metal magnetic thin film 1. However, this conventional method has the following drawbacks. Since the metal magnetic thin film 1 is heated through the substrate 3 made of glass or the like, thermal efficiency is poor.

2. Furthermore, since the entire system is heated, there is a risk of destroying the magnetic recording medium 4, which is sensitive to heat, so care must be taken when handling it.

3. Since there is a heat generation source 2, this interferes with the observation and monitoring of the transfer pattern during transfer. The object of the present invention is to provide a thermomagnetic transfer recording method which eliminates the drawbacks of the conventional thermomagnetic transfer recording method, has good thermal efficiency, and allows monitoring during transfer, and is constructed using glass or synthetic resin. A first magnetic recording medium is provided with a metal magnetic thin film layer having a magneto-optical effect on a substrate, and an insulating protective film layer is provided on the metal magnetic thin film layer. In the thermomagnetic transfer recording method for thermomagnetically transferring recorded information on a magnetic recording medium, the insulating protective film layer of the first magnetic recording medium is brought into close contact with the second magnetic recording medium, and the first magnetic recording medium is A current is passed only through the metal magnetic thin film layer, and Joule heat generated by this current gives the metal magnetic thin film layer a sufficient temperature rise for thermomagnetic transfer, and the metal magnetic thin film layer is heated from the glass or synthetic resin substrate side. The present invention is characterized in that thermomagnetic transfer is performed from the second magnetic recording medium to the first magnetic recording medium while monitoring transferred information using a magneto-optical effect.

Hereinafter, the present invention will be described in detail with reference to FIGS. 3 to 9. FIG. 3 shows an embodiment of the method of the present invention, in which 1 is a GdF'e amorphous thin film among the metal magnetic thin films;
3 is a glass substrate, 4 is a magnetic card among the magnetic recording media to be transferred, 7 is a terminal for passing a current through the GdFe amorphous thin film 1, and 8 is a power source.

Now, assuming that the resistance value of the αWe amorphous thin film 1 is R, by flowing a current 1 through the terminal 7, Joule heat proportional to RI2 is applied to the GdFe amorphous thin film 1.
occurs in Due to this internal heat, the coercive force Hc of the GdF'e amorphous thin film 1 itself decreases, and therefore the magnetic card 4
The magnetization of the GdF'e amorphous thin film 1 is promoted by the floating magnetic field H1 generated from the GdF'e amorphous thin film 1, and the transfer is preferably performed. In this case, an insulating protective film (not shown) is formed on the surface of the G-under-e amorphous thin film 1 in order to prevent oxidation due to temperature rise due to internal heat. In addition to the GdFe amorphous thin film 1, the thermomagnetic transfer recording medium may also include an Fe-Ni-CO alloy thin film, a MnBi thin film, or a TbFe thin film.
, amorphous thin film such as DyFe, has an appropriate resistance value R, and has a holding force Hc due to temperature rise due to energization.
All metal magnetic thin films that reduce the Here, some precautions should be taken when using the method of the present invention due to differences in the magnetic properties of materials.

Since the amorphous thin films GdF'E, TOFe, and DyFe are all ferrimagnetic materials, they form magnetization temperature curves shown in FIGS. 4, 5, and 6, respectively, and the magnetic compensation point TcO
mp and Curie point Tc. In addition, each a in FIGS. 4 to 6 indicates the saturation magnetic flux density Ms, and each b indicates the coercive force Hc. Furthermore, the curve in the black circle plot in FIG. Showing door Fe76,
The curve plotted with white circles in FIG. 5 shows T1)19F'E8l, the curve plotted with black circles shows Tb2lFe79, the curve plotted with white circles in FIG. 6 shows Dyl7Fe83, and the curve plotted with black circles shows Dy2lFe7. As shown in Figures 4 to 6, regardless of the material, the overall tendency is that the magnetic compensation point TcOmp, the Curie point Tc, and the saturation magnetic flux density M
As s approaches zero, the coercive force Hc changes greatly.

That is, as shown in each b of FIGS. 4 to 6, the coercive force Hc becomes large near the magnetic compensation point TcOm, and the coercive force Hc becomes large near the magnetic compensation point TcOm, and
It becomes zero at c. However, the value of the coercive force Hc itself varies depending on the material, and GdFe has an extremely small coercive force Hc at temperatures other than the vicinity of the magnetic compensation point TcOmp (see Figure 4).
TOFe and DyFe have a large coercive force Hc throughout including the magnetic compensation point TcOmp at temperatures other than around the Curie point Tc (see FIGS. 5 and 6). Therefore, when using a GclF'e amorphous thin film as a thermomagnetic transfer recording medium, it is necessary to ensure that the magnetic compensation point is near room temperature.
Such consideration is not necessary in the case of an amorphous thin film of TbFe or DyFe. Note that thermomagnetic transfer recording that utilizes a region where the coercive force Hc decreases near the magnetic compensation point TcOmp, such as in GdFe, is called compensation point thermomagnetic transfer recording, and TbF
Coercive force Hc near the Curie point Tc, such as e and DyFe
The method that utilizes the decreasing region of is called Curie point thermomagnetic transfer recording. Either method can utilize the phenomenon that the coercive force Hc decreases by increasing the temperature of the metal magnetic thin film. Next, in FIG. 3, when a current is directly passed through the GdFe amorphous thin film 1, the temperature t of the thin film and the current 1
The relationship between D and D is shown in FIG. 7 using the film thickness D as a parameter.

In addition, each film thickness has a relationship of D1<D2<D3<D4,
D1=0.1μM,. D2=0.15μM. ．． D3=0
．． 25 μM. ．． D,=0.5PTrL. Also,
Film thickness D3 (4). 25 μm), the temperature rise over time from the moment of energization is calculated using the current 1 as a parameter.
It is shown in the figure. In addition, each current is 11〈12×13×1
4, 11=120rr1A,,12=16
0rr1A,. 13=180n1A. ．． 14=220n
It is 1A. As can be seen from FIG. 8, it takes about 10 times for the temperature of the thin film to become constant, but it can be seen that the longer a large current is passed in order to reach a certain temperature TO, the shorter the time is required. Therefore, if a large current pulse is used, the temperature can be raised to a predetermined temperature in an extremely short time. By the method of the present invention detailed above,
FIG. 9 shows an example in which a recording pattern of a magnetic card is actually transferred by passing a current through a GdFe amorphous thin film, and the transferred pattern is observed using a polarizing microscope.

As explained above, in the thermomagnetic transfer recording method of the present invention, since the metal magnetic thin film itself, which is the transfer recording medium, is the heat generation source, it not only has good thermal efficiency but also minimizes heat diffusion to other parts such as magnetic cards. It has the advantage of being kept to a minimum.

Also, since it does not require an external heat generation source such as a heat ray lamp,
Even if thermomagnetic transfer recording is performed directly under a polarizing microscope, the field of view is not obstructed and the progress during transfer can be observed step by step. From this point of view, if the method of the present invention is combined with an optical system such as a polarizing microscope, a transfer light reproducing device or the like can be realized.

[Brief explanation of drawings]

Figures 1a and b are polarized light micrographs showing transfer patterns obtained by transferring the music pattern and test pattern of a magnetic card onto an αFe amorphous thin film by simple magnetic transfer, and Figure 2 is a conventional thermomagnetic transfer recording method. FIG. 3 is an explanatory diagram showing a specific example of the thermomagnetic transfer recording method of the present invention. Figures 4, 5 and 6 are examples of metal magnetic thin films, such as GdF'E.
, TbFe, and DyFe amorphous thin films, each figure a relates to the saturation magnetic flux density, and each figure b relates to the coercive force. No. 7 is a graph showing the relationship between the current applied and temperature, with film thickness as a parameter, and Fig. 8 is a graph showing the relationship between current application time and temperature, showing the current as a parameter in the case of film thickness D3 in Fig. 7. It is. 9th
The figure is a polarized light micrograph showing a pattern transferred from a magnetic card to a GdFe amorphous thin film by the method of the present invention. In the drawing, 1 is a metal magnetic thin film (αFe amorphous thin film), 3 is a substrate such as glass, 4 is a magnetic recording medium,
5 and 6 are their magnetic coating films and bases, 7 is a terminal for flowing current, 8 is its power source, TcOmp is a magnetic compensation point,
Tc is the Curie temperature, Hc is the coercive force, and Hc is the saturation magnetic flux density.

Claims (1)

[Claims] 1. A first magnetic recording medium in which a metal magnetic thin film layer having a magneto-optic effect is provided on a glass or synthetic resin substrate and an insulating protective film layer is provided on this metal magnetic thin film layer has already been magnetically recorded. In the thermomagnetic transfer recording method for thermomagnetically transferring recorded information on a second magnetic recording medium, the insulating protective film layer of the first magnetic recording medium is brought into close contact with the second magnetic recording medium, and the first A current is passed only through the metal magnetic thin film layer of the magnetic recording medium, and Joule heat generated by the current gives the metal magnetic thin film layer a sufficient temperature for thermomagnetic transfer, and the metal magnetic thin film layer is transferred from the glass or synthetic resin substrate side to the metal magnetic thin film layer. A thermomagnetic transfer recording method, characterized in that thermomagnetic transfer is performed from the second magnetic recording medium to the first magnetic recording medium while monitoring transferred information using a magneto-optic effect of a thin film layer.