JPH1031813A - Magnetic card and manufacturing method thereof - Google Patents

Abstract

(57) [Summary] [PROBLEMS] Although information can be recorded easily, it is difficult or impossible to erase or rewrite the recorded information, so it is impossible to erase or write information for the purpose of forgery. Provided is a magnetic card having an excellent anti-counterfeiting effect without using a simple magnetic recording / reproducing device, and further having a high coercive force, which makes it difficult or impossible to erase or rewrite information once recorded, and a method of manufacturing the same. thing. SOLUTION: In a magnetic card provided with a magnetic layer for performing magnetic recording and reproduction on a substrate, the magnetic layer is a magnetic thin film formed by using a sputtering method.
General _{formula, R x T 100-xy M} y ( where, R represents one or more of the rare earth elements including Y as an essential component sm, T is a transition metal (Fe mainly composed of Co, Co, Ni ), Where M is
Si, Ti, Al, Ga, V, Cr, Mn, Cu, Zr, Nb, Mo, Pd, Hf, Ta, W, Pt, Au). 16.0-22.0 (a
t%), the composition value y of M is in the range of 0 ≦ y <30 (at%).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic card and a method of manufacturing the same, and more particularly, it is difficult or impossible to rewrite or erase predetermined information recorded.
The present invention relates to a magnetic card excellent in forgery prevention and a sono manufacturing method.

[0002]

2. Description of the Related Art Magnetic cards used as tickets, telephone cards, prepaid cards, etc., are:
Each time a card is used, it is used by rewriting predetermined information such as a balance on a magnetic recording layer provided on the card by a predetermined device. In order to prevent forgery, these cards are provided with a protective layer on the magnetic recording layer, a multilayered magnetic recording layer, or a punched hole in the card each time the card is used.

[0003]

However, with the spread of magnetic cards, the technology of reproducing and recording information on magnetic cards has also been developed, and the information recorded on magnetic cards can be easily read and further written. It has become possible.
Specifically, every time a magnetic recording card is used, all information, including new information, is rewritten so that it is overwritten on old information. Information can be rewritten in
Forgery of cards has been made easier, and forgery of magnetic cards has increased remarkably in recent years.

The cause is that the coercive force of the magnetic layer is 2-3.
It is considered to be low kOe. That is, if the coercive force is low, information can be easily rewritten by a conventional magnetic recording / reproducing apparatus, and the card can be forged.

In view of the above situation, the technical problem of the present invention is to record information easily, but it is difficult (impossible) to erase or rewrite the recorded information. It is an object of the present invention to provide a magnetic card in which information cannot be erased or written and a method of manufacturing the same.

Another technical object of the present invention is to provide a magnetic recording card having an excellent anti-counterfeiting effect without using a special magnetic recording / reproducing device as compared with the conventional one, and a method of manufacturing the same. It is in.

Another object of the present invention is to provide a magnetic card which has a high coercive force and makes it difficult or impossible to erase or rewrite information once recorded, and a method of manufacturing the same.

[0008]

Means for Solving the Problems The present inventors first record at the time of initial information recording while leaving one or more unrecorded portions in the longitudinal direction, and thereafter record new information sequentially. In this study, we considered a method for recording new information in unrecorded parts without erasing existing information. As a result, a special magnetic recording / reproducing apparatus is not required, and a magnetic card having an excellent anti-counterfeiting effect and a manufacturing method thereof have been found, and the present invention has been accomplished.

According to the present invention, in a magnetic card having a magnetic layer for performing magnetic recording and reproduction on a substrate, the magnetic layer is a magnetic thin film formed by using a sputtering method.
The magnetic thin film of the general _{formula, R x T 100-xy M} y ( where,
R is at least one selected from rare earth elements containing Sm as an essential component and Y, and T is at least one selected from transition metals (Fe, Co, Ni) containing Co as a main component. , M are Si, Ti, A1, Ga, V, C
r, Mn, Cu, Zr, Nb, Mo, Pd, Hf, T
a, W, Pt, and Au), and R has a composition value of 16.0 to 22.0;
A magnetic card is obtained, wherein the composition value y of M is in the range of 0 ≦ y <30 (all at%).

According to the present invention, in the method for manufacturing a magnetic card, the magnetic thin film may be formed at a substrate temperature of 120.
A method for manufacturing a magnetic card, characterized in that the magnetic card is formed by sputtering at a temperature of not more than ° C.

The magnetic card of the present invention has a higher coercive force and a superior magnetic property as compared with the conventional magnetic card.

In the present invention, the coercive force of the magnetic card is 3.0 kOe or more because erasing or overwriting of recorded information is difficult (impossible), and the coercive force is required to express coercive force effectively. It is preferable to have a magnetization of 25% or more of the saturation magnetization at an applied magnetic field of 1/2 or less.

[0013] In the present invention, limited UmaYukari the above composition formula, the _{R x T 100-xy M y} , x is 1
If it is less than 6.0 at%, the coercive force is reduced to 22.0 at%.
This is because the magnetization is undesirably reduced above.
This is because if M is at least 30 at%, the coercive force decreases, which is not preferable. Further, when the substrate temperature is 120 ° C. or higher when performing sputtering, the coercive force decreases, which is not preferable.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) Sm-C of Various Compositions
Using an o alloy target, Ar gas pressure 20 mTorr,
At a substrate temperature of 25 ° C, polyethylene terephthalate (PE)
A magnetic layer having the composition shown in Table 1 below was formed by sputtering on the substrate T) to produce a magnetic card. The magnetic properties of the obtained magnetic card were measured using a vibrating sample magnetometer (VSM). The results are shown in Table 1 below.

[0016]

[Table 1] When the Sm value was 16.0 at% or more and 22.0 at% or less, a large coercive force and good magnetization were obtained.

Further, when a conventional reader / writer (recording magnetic field, 5 kG) was used to perform recording and reproduction on each card by the FM method, good recording signals were detected on all cards. Next, when the recording signal was erased using this magnetic head, the Sm value was 15.2 at% and 23.0 at%.
In the card of at%, the recording signal attenuated to an output of 10% or less before erasing and was easily erased, and in other cards, the recording signal remained at an output of 30% or more before erasing and was hard to be erased.

(Second Embodiment) Using an Sm-Co alloy target, an Ar gas pressure of 20 mTorr and a substrate temperature of 5
Sm19.1xat% on PET substrate at ~ 130 ° C,
A magnetic layer having a composition of 80.9 at% Co was formed by sputtering to produce a magnetic card. The magnetic characteristics of the magnetic card S. The results measured using M are shown in Table 2 below.
At a substrate temperature of 120 ° C. or less, a large coercive force and good magnetization were obtained.

[0019]

[Table 2]

(Third Embodiment) Sm-C of Various Compositions
Using an o-alloy target and a method similar to that of the first embodiment, a magnetic layer having the composition shown in Table 3 below was formed on a PET substrate to produce a magnetic card. The magnetic characteristics of the obtained magnetic card were S. M was measured. The results are shown in Table 3 below.

[0021]

[Table 3]

Good results were obtained even when the elements shown in Table 3 were added. Further, when recording was performed on each card and erasing was performed in the same manner as in the ninth embodiment, the recording signal remained at 30% or more of the output before erasing in all the cards, and was difficult to be erased.

Incidentally, even if two or more kinds of additive elements are added,
It is easily assumed that good results are obtained.

(Fourth Embodiment) Sm-C of Various Compositions
Using an o- (Al, Cr) alloy target, a magnetic layer having the composition shown in Table 4 below was formed on a PET substrate in the same manner as in the first embodiment to produce a magnetic card. The magnetic characteristics of the obtained magnetic card were S. M was measured.
The results are shown in Table 4 below.

[0025]

[Table 4]

A decrease in coercive force was observed in the magnetic powder containing 2.5 at% or more of Al, Cr and W. Also, Si,
Ti, Ga, V, Mn, Cu, Zr, Nb, Mo, P
When d, Hf, Ta, Pt, Au, and W are added,
Similar good results were obtained with additions of less than 2.5 at%.

[0027]

As described above, according to the present invention, the magnetic layer having a coercive force of 3.5 kOe or more and having a magnetization of 25% or more of the saturation magnetization at an applied magnetic field of 1/2 or less of the coercive force can be used for information. It is easy to record, but focuses on the fact that it is difficult or impossible to erase or rewrite the recorded information. In the method of magnetic recording in the longitudinal direction of the magnetic recording medium in the longitudinal direction, firstly, the initial information recording is performed. At the time of recording, one or more unrecorded portions are left in the longitudinal direction and recording is performed. After that, when new information is sequentially recorded, new information is recorded in the unrecorded portion without erasing existing information. be able to. Therefore, according to the present invention, although information can be recorded easily,
Since it is difficult or impossible to erase or rewrite recorded information, it is possible to obtain a magnetic recording card that cannot erase or write information for the purpose of forgery.

Therefore, the present invention is extremely useful industrially.

Claims (2)

[Claims] 1. A magnetic card having a magnetic layer for performing magnetic recording and reproduction on a substrate, wherein the magnetic layer is a magnetic thin film formed by using a sputtering method. _x T _100-xy M _y (where, R represents at least one selected from among rare earth elements including Y as an essential component Sm, T is a transition metal mainly containing Co (Fe, Co, Ni ) At least one selected from
Species, M is Si, Ti, A1, Ga, V, Cr, Mn,
Cu, Zr, Nb, Mo, Pd, Hf, Ta, W, P
t, and at least one selected from Au), R has a composition value of 16.0 to 22.0, and M has a composition value y of 0 ≦ y <30 (all at%). A magnetic card, characterized in that: 2. The method for manufacturing a magnetic card according to claim 1, wherein said magnetic thin film is formed by sputtering at a substrate temperature of 120 ° C. or less.