JPH04188433A - Manufacture of magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve recording reproducing characteristics by specifying the relationship of the scanning width of electron beams and a distance between the surface of a ferromagnetic metallic material in a crucible and a minimum incident angle section to a non-magnetic base body of evaporated particles when the crucible, in which the ferromagnetic metallic material is melted, is irradiated with electron beams and the material is heated and evaporated. CONSTITUTION:When a ferromagnetic metallic layer is formed onto a non- magnetic base body 2 through an electron-beam heating evaporation method, the relationship of H/(L/2)>=0.8 is satisfied in the scanning width L of electron beams and a distance H from the surface of a ferromagnetic material in the crucible to a minimum incident angle section to the non-magnetic base body of evaporated particles when the ferromagnetic metallic material previously filled into the crucible 3 is irradiated with electron beams while scanning electron beams and heated and evaporated and deposited. The high molecular film, etc., of polyimide, polyester, polyethylene terephthalate, etc., are preferable as a non-magnetic substrate 2 used as a magnetic recording medium. Accordingly, recording reproducing characteristics can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method of manufacturing a magnetic recording medium. More specifically, the present invention relates to a method of manufacturing a magnetic recording medium with improved recording/reproducing characteristics.

[Prior Art] With the increasing demand for high-density recording technology, active technological improvements have been made in various fields including optical recording and semiconductor memory. In particular, in the field of magnetic recording, research has been actively conducted on magnetic thin films such as Co--Ni5 Co--Cr as high-density recording materials in place of conventional magnetic powder-coated recording media.

・In general, ferromagnetic metals such as cobalt or their alloys (
For example, a magnetic recording medium having a magnetic thin film made of Co-N1) is produced by melting a ferromagnetic metal or its alloy by electric f-ray irradiation in a crucible installed in a vacuum chamber, and then releasing the heated and evaporated metal vapor. It is formed by adhering it to a J1 magnetic material made of plastic or film such as polyester.

[Problems to be Solved by the Invention] In the electron beam irradiation, a method is used in which the electron beam is scanned at a predetermined distance in order to uniformly heat the metal in the crucible.

However, with this method, especially when using a large device, if the electron beam is at the irradiation spot or at the end of the crucible, the particles reaching the nonmagnetic substrate will be dispersed at an angle of incidence or in an oblique direction.
The growth of columnar grains and the orientation of crystals deteriorate, which adversely affects recording +JF characteristics.

Therefore, an object of the present invention is to solve the problem of the incident particle angles being obliquely dispersed in the prior art, and to provide a magnetic recording medium with improved recording and reproducing characteristics.

[F Steps to Solve the Problems] In order to achieve the above objects, the present invention provides a magnetic recording medium in which a ferromagnetic metal thin film layer is formed on a non-magnetic substrate by a continuous deposition method using electron beam heating. In the manufacturing method, when a crucible in which a ferromagnetic metal material is melted is irradiated with an electron beam to heat and evaporate it, the scanning width of the electron beam and the contact between the surface of the ferromagnetic metal material in the crucible and the evaporated particles on the non-magnetic substrate are determined. Provided is a method for manufacturing a magnetic recording medium characterized in that the distance H to the lowest incident angle portion satisfies the following relationship: H/(L/2)≧0.8.

[Function] In forming a ferromagnetic metal layer on a non-magnetic substrate by electric r-ray heating evaporation method, the present invention has carried out extensive experiments for many years. The material is electric r1i! When performing vapor deposition by heating and evaporating by irradiating while scanning, the scanning width of the electron beam shown in Fig. 1 (a),
And, the distance 1111tH from the surface of the ferromagnetic metal material in the crucible to the lowest incident angle part of the evaporator r to the magnetized ff1 substrate shown in FIG. 1(b) is H/(L/2)≧0.8. It has been discovered that a magnetic recording medium with improved recording characteristics can be obtained by satisfying the following relationship.

This is done by increasing the distance from the surface of the ferromagnetic metal material in the crucible to the nonmagnetic substrate and/or by narrowing the scanning width of the electron beam to reduce the incident angle dispersion of the evaporated particles onto the nonmagnetic substrate. This reduces the amount of particles and makes the grain growth and crystal orientation uniform.

However, due to the scanning width of the electron beam and the evaporation from the surface of the ferromagnetic metal material in the crucible! 7 When the distance #H to the lowest incident angle part of T to the non-magnetic J^ body is H/ (L/2) < 0.8, when the electric Y-ray irradiation spot position is at the end of the crucible In this case, the angle of incidence of the particles reaching the nonmagnetic substrate is extremely dispersed, and the growth of the particles and the orientation of the crystals are changed.

The manufacturing method of the present invention includes vertical deposition and oblique deposition.
Continuous deposition using electron beam heating can be carried out for all types of deposition.

As the nonmagnetic substrate used in the magnetic recording medium of the present invention, polymer films such as polyimide, polyester, polyethylene terephthalate, etc. are suitable.

[Example code] Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 11 Outside ↓ 2''Y A 10 μm thick polyethylene terephthalate film and a Co-20at%Ni alloy were added to a continuous vacuum evaporation apparatus and vacuum degassed to a pressure of 1X10-5 Torr or more. Next, the beam of the electron gun is scanned to irradiate the Co-Ni alloy in the crucible to heat and evaporate it to form a film with a thickness of 0 on the Bolier/terephthalate film l- running along the rotating drum.
．． A ferromagnetic metal layer made of Co-N1 with a thickness of 2 μm? J.R.J.
Formed. At this time, as shown in Table 1, the scanning width of the electron beam and the distance H between the surface of the ferromagnetic metal material in the crucible and the lowest incident angle portion of the evaporated particles onto the nonmagnetic substrate were varied. Thereafter, it was cut into a predetermined width to produce a magnetic tape.

Table 1 Magnetic properties of the magnetic tapes in each example were measured using a sample vibrating magnetometer. In addition, 7MHz when recording a 7MHz positive wave using an electromagnetic conversion characteristic measuring device
The raw output of one ear was measured. Table 2 shows the squareness ratio, 7 MHzrJ, and main output (standard square tape ratio) of the tapes of each example.

Table 2 As is clear from the results shown in Table 2, Examples 1 to 4
The magnetic tape obtained by satisfying the requirement of H/(L/2)≧0.8 has a higher squareness ratio and 7MHz M main output than the magnetic tape of Example 5 which does not meet this requirement. According to the magnetic tape manufacturing method of the present invention,
Recording and reproducing characteristics can be improved.

[Effects of the Invention] As explained above, according to the present invention, a ferromagnetic metal material is melted in order to form a ferromagnetic metal thin film layer on a non-magnetic substrate by a continuous oblique evaporation method using electron beam heating. When a crucible is irradiated with an electron beam to heat and evaporate, the scanning width of the electron beam and the distance H between the surface of the ferromagnetic metal material in the crucible and the lowest incident angle of the evaporated particles on the non-magnetic substrate are H/ (L/2)
If vapor deposition is carried out in such a way that the ratio of ≧0.8 is satisfied, a magnetic recording medium with recording and reproducing characteristics opposite to f can be obtained.

[Brief explanation of drawings]

Fig. 1(a) is a schematic diagram of the evaporation source and drum in a continuous diagonal 74-stroke device as seen from the side, and Fig. 1(b) is a schematic diagram of the evaporation source and drum in the continuous oblique evaporation device as seen from the front. It is. 1... Rotating drum, 2... Non-magnetic substrate, 3... Crucible.

Claims (1)

[Claims] (1) In a method for manufacturing a magnetic recording medium that involves forming a ferromagnetic metal thin film layer on a nonmagnetic substrate by a continuous vapor deposition method using electron beam heating, a crucible in which a ferromagnetic metal material is melted is irradiated with an electron beam. During heating and evaporation, the scanning width L of the electron beam and the distance H between the surface of the ferromagnetic metal material in the crucible and the lowest angle of incidence of the evaporated particles onto the non-magnetic substrate are H/(L/2)≧0. .8 A method for manufacturing a magnetic recording medium, characterized by satisfying the following relationship.