JPH04132014A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain the magnetic recording medium suitable for recording and reproducing of signals of a wide band by forming a high-concn. region of an element of either O or N near at least 40 deg. incident angle component of vapor deposited fine particles. CONSTITUTION:The magnetic recording layer is so formed as to be divided to a vapor deposited part 3 where fine columnar particles 2 formed on a film 1 begin to grow from 90 deg. incidence and grow nearly to 40 deg. and a perpendicularly magnetized part 4 where the particle are further grown to thetamin 20 to 10 deg.. Further, the high-concn. region of the O or N is formed in the depth direction corresponding to the X-X part of Fig. The magnetic recording medium which is magnetically loosened in the bond in the vapor deposited fine columnar particles, is improved in noise, is excellent in C/N over a wide band and has good durability is obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic recording medium suitable for high-density magnetic recording.

Conventional technology The history of magnetic recording is a history of high density recording, and with the demand for miniaturization of magnetic recording equipment and the increase in the amount of information due to changes in broadcasting methods, there will be a strong demand for even higher density recording in the future, and ferromagnetic metal It is hoped that magnetic recording media with thin films as magnetic recording layers will be put to practical use, and some of them have been put into practical use with the high-band 8mm TR, which achieves the highest density recording for consumer use, and improvements are being made.

The current configuration of magnetic recording media is that fine particles are arranged on a polyester film, and then CO-Ni (Ni
:20~zswt%) is electron beam evaporated in oxygen, and a protective lubricant layer is further placed on top of it.
Ni -0@ has a one-layer structure to a three-layer structure, but all of them are deposited using a continuous angle-of-incidence deposition method starting from 90 degrees of incidence along a rotating can, in combination with deposition in oxygen. A lubricant is placed on the ferromagnetic metal thin film, and a backing is placed on the other side of the polyester film. A coat layer is often provided.

Problems to be Solved by the Invention However, with the above structure, in order to record and reproduce signals in a wider band, it is necessary to increase the film thickness and increase the coercive force. A narrow gap head with high magnetic flux density is required,
The current state of the art is insufficient, and it has been desired to cover a wide band with a magnetic recording medium that can be efficiently magnetized by applying current magnetism.

The present invention is intended to solve these problems, and it is an object of the present invention to provide a magnetic recording medium suitable for recording and reproducing broadband signals compatible with high-definition broadcasting systems.

Means for Solving the Problem In order to solve this problem, the present invention provides a rotational angle from 90 degrees to θll1n (θnin: 20 degrees to 10
A high concentration region of either O or H is formed near the incident angle component of at least 40 degrees of the vapor-deposited fine particles composed of the incident angle component up to 40 degrees.

The magnetic recording medium of the present invention has the above-described structure, so that the interior of the deposited columnar fine particles is magnetically divided into the region from 90 degrees to nearly 40 degrees, where the in-plane magnetization component is strong, and the region from 40 degrees to 610 degrees, where the perpendicular magnetization component is strong. The coupling is loosened to improve noise, and unlike the conventional laminated layer of in-plane magnetization film and perpendicular magnetization film, the columnar fine particles are integrated, allowing for faster sliding speeds for wider bands with the magnetic head. By being able to provide good friction durability and maintain a high C/N under various conditions, it is possible to achieve a high C/'N level as a practical level.

Embodiments Hereinafter, embodiments of the present invention will be described based on the drawings.

The magnetic recording medium of the first embodiment of the present invention has a shape-imparting layer disposed on a polymer film such as polyethylene terephthalate, polyethylene naphthalate, polyphenylene sulfide, polyetherethergeton, polyimide, etc. A protective lubricating layer is placed on top of the protective lubricating layer, and a back coat layer is placed on the other side of the polymer film, and then processed into a tape shape. Although the protective lubricating layer and the back coat layer require appropriate modifications, they do not particularly limit the present invention.As shown in FIG. Columnar fine particles 2 formed on 1 (including those with θl1in (θli
n: 20 degrees to 10 degrees). Fig. 2 shows the profile of CO element and oxygen in the thickness direction measured by Auger electron spectroscopy. In the figure, a high concentration area of 0 or N is formed in the depth direction corresponding to the section XX in FIG.

The shape of this profile is just an example, and there is no particular limitation as to what kind of gradient the concentration peak should be near 40 Majin shots.

To obtain the configuration of the magnetic recording medium of the embodiment of the present invention, Co or Co-Ni (Ni:
When performing electron beam evaporation of 5 to 28 wt%), there is a method of introducing oxygen throughout the area and irradiating oxygen ions close to an angle of incidence of 40 degrees, or adjusting the conditions for irradiating the evaporation area with an oxygen ion beam at an angle of incidence of 40 degrees. The same applies to N ions, which can be modified as appropriate without being limited to what can be obtained by changing the ions according to the conditions.

Hereinafter, specific examples of the present invention will be described in comparison with comparative examples.

20 particles/μ2 of 5i02 with a diameter of 100A were arranged on a polyethylene terephthalate film with a thickness of 10μm,
Furthermore, CO or Co--Ni (Ni: 22 wt%) was electron-beam evaporated onto it along a cylindrical can with a diameter of 1 m. When performing sub-beam evaporation, the oxygen ion beam or nitrogen ion beam is scanned over the entire area, starting from 90 degrees of incidence, and depositing up to θll1n (θlin: 20 degrees to 10 degrees), and adjusting the scanning time. The ion beam was configured so that a large amount of the ion beam was irradiated near 40 degrees of incidence.

For condition A, CO is 0.1 from 90 degrees to 40 degrees.
8key oxygen ion beam while electron beam evaporation under the condition that μ, 0.14 μm from 40 degrees to 20 degrees.
, 106 μA/-, nearly 40 degrees (actually 39 degrees ~
40.5 degrees) for 3.5 times the residence time in other regions to form an oxygen peak region and achieve a saturation magnetic flux density of 65 degrees.
00 (G), vertical coercive force 1500 (Oe), and horizontal coercive force 1100 (Oe). While performing electron beam evaporation under the conditions of 0.16 μm from 40 degrees to 14 degrees, the whole was 2 x 1
G ((Torr) oxygen atmosphere, near 40 degrees 6
key, irradiate with an oxygen ion beam of 55 μA/-,
An oxygen concentration peak 2.3 times that of other regions is formed near 40 degrees, with a saturation magnetic flux density of 6700 (G), a vertical coercive force of 1600 (Oe), and a horizontal coercive force of 1150 (Oe).
0 film formed under 0 condition C has a diameter of 50 mm.
Co -N (Ni:24
wt%) was electron beam evaporated, and the thickness was 0.06 μm from 90 degrees to 40 degrees, and 0.12 μm from 40 degrees to 12 degrees. At that time, oxygen is introduced from the outside,
In an oxygen partial pressure of 3 x 10' (Torr), 5 key, 56 μA/ail oxygen ions are irradiated near 40 degrees, and an oxygen concentration area 2.7 times higher than the minimum concentration area (compared to the minimum concentration area) is irradiated near 40 degrees. ) with a saturation magnetic flux density of 7000 (G
), vertical coercive force of 1550 (Oe), and horizontal coercive force of 1060 (Oe) under 0 conditions, in which a C0-0 film was formed, no oxygen was introduced and 11 keys, 90
Nitrogen ions of μA/- were irradiated, and a peak of 2.5 times the nitrogen concentration was formed near 40 degrees. The deposition conditions were the same as Condition C. The obtained film has a saturation magnetic flux density of 6400 (
G ), vertical coercive force 1380 (Oe), horizontal coercive force 12
The one under 0 condition E, which had an Oe of 90 (Oe), is a comparative example.
0.1μm of Co in oxygen at 6X10' (Torr)
Co was then vapor-deposited thereon at an incident angle ranging from 40 degrees to 15 degrees. At that time, oxygen was introduced from the side regulating the incident angle at 15 degrees, and gas A was introduced from the side regulating the incident angle at 40 degrees.The first layer has a saturation magnetic flux density of 4
800 (G), horizontal coercive force 1100 (Oe), vertical coercive force 1000 (Oe), second layer saturation magnetic flux density 6200 (
G), horizontal coercive force of 1200 G (Oe), and vertical coercive force of 150 G (Oe), Fombrin AH2001, commercially available as a perfluoropolyether, manufactured by Montageson was applied on each deposited film at 40 A! A back coat layer containing a 1:1 blend of carbon and polyester resin is applied to the fabric.
．． Comparative evaluation was performed using a magnetic nurse with a thickness of 5 μm and a width of 8 mm. The evaluation was done by modifying an 8mm video deck and setting the relative speed to 3.8 m/sec and 7.6 m/sec.
The recording frequency was changed to 7 (MH2), 14 (M
As H2), the C/N is expressed in comparison with the noise at 1 (MH2) from the carrier. The results are summarized in Table 1.

(Margin below) Next, a second embodiment of the present invention will be described.

In this second embodiment, the growth direction on the obliquely deposited film is on the opposite side,
θsin (20 degrees ~
The magnetic recording medium of the embodiment of the present invention is one in which a high concentration region of O or N is formed at least near an incident angle component of 40 degrees of vapor-deposited fine particles composed of an incident angle component of up to 10 degrees). With this configuration, the in-plane magnetization component-dominated part of the incident angle component from 90 degrees to nearly 40 degrees and the perpendicular magnetization component-dominated part from 40 degrees to 015 degrees grown in opposite directions formed on the obliquely deposited film are separated. By forming an integrated columnar fine particle, magnetic separation is achieved in a three-layer structure, which improves noise. On the long wavelength side, the obliquely deposited film part and the obliquely deposited film part differ from 90 degrees to 40 degrees in the diagonal deposition direction. The part of the incident angle component up to nearly 100 degrees plays the role, and the part from 40 degrees to θmin degrees plays the role on the short wavelength side, so that it is possible to improve the output over a wider band. On the long wavelength side, the diagonal deposition directions are opposite, which results in more in-plane deposition and improved low-frequency noise.
/N contributes to improvement.

FIG. 3 is an enlarged cross-sectional view of the main parts of a magnetic recording medium according to a second embodiment of the present invention. In the figure, 5 is a substrate such as a polymer film;
6 is Co, Co-Ni, Co-0゜Co-N
Columnar fine particles constituting the obliquely deposited film such as i-0, 7 is Co-0, co-Ni-0 or co-N, Co
-Ni -N columnar fine particles 7
is deposited at an angle of 90 degrees, and the growth direction is opposite to that of the columnar fine particles 6.
(θsin = 20 degrees to 10 degrees) degree range evaporation part 9
The magnetic recording medium according to the second embodiment of the present invention has a magnetic recording medium having the above-described structure. A protective lubricating layer is placed on the recording layer, a back coat layer is placed on the other side of the polymer film, and the tape is used as a magnetic tape of a predetermined width.

A more specific explanation will be given below using comparative examples and comparisons.

A spherical polymethyl methacrylate with a diameter of 400 A is flattened in the height direction on a polyethylene naphthalate film with a thickness of 11 μm so that the average height is 18 oA,
~6 pieces/μ2 Co - Co -
Ni (Ni: 26wt%) at 4×10-5 to 6
This was done by electron beam heating in x1O-5 (■o'') oxygen.The formed film thickness was 0.08 μm.

Furthermore, the direction of the obliquely evaporated part of the columnar fine particles is integrated with the obliquely evaporated part formed by the incident angle component that crosses the opposite side, and the minimum incident angle is 20 degrees, 15 degrees, and 10 degrees. Vapor deposited films A, B, and C were formed. At this time, an oxygen ion beam was directed to the deposition area at the same time as the deposition, and the scanning conditions were adjusted to 8 kV (15 to 150 μA/cj) so that oxygen atoms were concentrated at a high concentration in the portion where the incident angle was 40 degrees.

FIG. 4 shows the profile of Co element and oxygen in the thickness direction measured by Auger electron spectroscopy.

As a reference example, after performing oblique evaporation, start oblique evaporation in the same direction as that direction, form a high concentration area of oxygen near the 40 degree incident area, and then set the minimum incident angle to 15 degrees. Vapor deposition and ion irradiation were performed. In addition, in the comparative example, diagonal deposition was performed at an angle of 40 degrees from 90 degrees in the opposite direction to the obliquely deposited film.
x10"5 to 5 x 1 O-5 (TOrr) oxygen, and then oxygen gas was introduced from the oxygen introduction boat near the 40 degree incident part from 40 degrees to 15 degrees to form a perpendicularly magnetized film. Formed.

In each case, 60% of Fomblin Z-25 (commercially available as perfluoropolyether manufactured by Montegison) was coated on the magnetic layer, a back coat layer of 0.5 μm was coated on the opposite side, and an 8 mm wide magnetic tape was coated on the magnetic layer. And so.

Modified 8m+ video deck to perform broadband recording,
/N and evaluate durability by repeated driving.

The tape conditions and evaluation results are summarized in Table 2.

(The following is a blank space) In addition, the vapor deposited films A to C are 0.75 (M
Even on the low frequency side of Hzl 〒2.2 to +2.6 (dB)
Since the C/N is good, the C/N improvement effect in a wide band is large.

Effects of the Invention As described above, the present invention has excellent broadband C/N,
In addition, a magnetic recording medium with good durability can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a magnetic recording medium in a first embodiment of the present invention, FIG. 2 is an Auger profile of the same, FIG. 3 is a cross-sectional view of a magnetic recording medium in a second embodiment of the present invention, and FIG. This is the same Auger profile. DESCRIPTION OF SYMBOLS 1... Funi Lum, 2... Columnar fine particles, 3... Oblique vapor deposition part, 4... Perpendicular magnetization part, 5... Substrate, 6.7
... Columnar fine particles, 8... Oblique vapor deposition part, 9... Vapor deposition part. Agent Yoshihiro Morimoto

Claims (1)

[Claims] 1. θmin (θmin
: A high concentration region of either O or N is formed at least near the 40 degree incident angle component of the vapor deposited fine particles composed of the incident angle component from 20 degrees to 10 degrees). magnetic recording medium.