JPS6344314A - Magnetic recording medium having inter-layer composition transient zone - Google Patents

Abstract

PURPOSE:To obtain a magnetic recording medium which has good reproducibility, optimized coercive force and high squareness ratio in magnetic characteristics and has no intra-surface magnetic anisotropy by providing a prescribed transient zone between constituting layers. CONSTITUTION:The magnetic recording medium is formed by providing a magnetic layer which is a component A and an underlying layer which is a component B on a nonmagnetic substrate. The range where 90wt% component A and 10wt% component B to 10wt% component A and 90wt% component B; i.e., transient zone, is set at 100-1,000Angstrom in the thickness direction of the components A, B. The magnetic recording medium having the good reproducibility, optimized coercive force and high squareness ratio in the magnetic characteristics and having no intra-surface magnetic anisotropy is obtd. by providing such transient zone.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to various types of media related to magnetic recording, such as magnetic tapes, magnetic disks, 70-ply disks, and the like.

[Conventional technology]

In magnetic recording, with the demand for higher recording density, the magnetic layer is a discrete type magnetic layer in which a magnetic paint containing magnetic powder is coated during binding so that the magnetic powder is in a discrete state. From there, we moved on to a deposited magnetic layer in which a magnetic material is deposited continuously or intermittently on the base surface of a substrate etc. using a vacuum evaporation method or a sputtering method in which the magnetic material is densely packed. The perpendicular recording method, which can achieve dramatically higher density than the hydrographic recording method, has attracted attention and has reached the stage of practical application. General trends in magnetic recording are also reflected in the field of magnetic disks. That is, as compact high-density devices such as 3.5- to 5-inch disks are developed and small-diameter disks are used, the reproduction output and S/N ratio deteriorate due to a decrease in the relative speed between the small-diameter disk and the magnetic head. It has been attempted to compensate for this by replacing it with a high-density magnetic layer that has a higher output. As long as the magnetic layer is aimed at high density, it is essential to be of a deposition type, but the magnetic layer formed by vacuum evaporation or sputtering has a shape in which ml of columnar or ordinary particles of magnetic material are concentrated. , the size of the pillars, the bulk jlt li'L crystals, the size and shape of the fleps-like gaps between the unit crystals vary depending on the vapor deposition conditions. Therefore, in a magnetic layer having such a shape, it is necessary to provide a holding layer:/1. This deposited magnetic film has better magnetic properties than a discrete magnetic film containing a binder such as a synthetic resin, such as a conventional coated film, and the manufacturing process is simpler. In addition, the recording quality has improved, and a material with excellent properties as a high-density medium has been obtained.In particular, the cobalt-nickel alloy film is a hard material,
It is evaluated as a very good magnetic recording medium. Technological efforts to expand the functionality and improve the performance of magnetic recording media as described above have not only covered a wide range of materials and additives, but also extended to the structure of the media layer. There are known examples of media having complicated layer configurations, such as protective layers, JWi layers, anti-corrosion layers, lubricating layers, and magnetization auxiliary layers, which cannot be addressed with a single layer. As the layer structure becomes more i-layered, attention is also paid to interlayer ripple effects and layer boundary effects.For example, the development of magnetic properties of a cobalt-nickel magnetic layer with a chromium layer as a base depends on the crystal orientation of the chromium layer or its thickness. On the contrary, as a suppressing factor, theoretical considerations such as those required for the oxidation of the epidermis of the abdominal layer have been made, and at the same time, a phenomenological investigation has been carried out, and a non-magnetic substrate The coercive force and squareness ratio (residual magnetization) of a magnetic recording medium having two or more vapor-deposited layers, especially a layer I3 structure in which a magnetic layer with a non-magnetic underlayer is provided on the substrate, are investigated. Various efforts have been made to improve the magnetization (/saturation magnetization), and as a result, methods have been developed to increase the
．． Form a chromium layer of 5 μl and adhere to the sublayer to a thickness of 0.1 μl.
It is known that depositing a cobalt-based magnetic layer of about 100 ml gives favorable results, but the lll! ! The structure of the theory is still unclear, and there is a lack of trial and error on optimization conditions.

[Purpose of the invention]

An object of the present invention is to provide a magnetic recording medium having optimized coercive force with good reproducibility, high squareness ratio, and no in-plane magnetic anisotropy in magnetic properties. In addition, the optimized coercive force is 400 to 10,000 e,
The high squareness ratio is aimed at 0.75 to 0.98.

Structure 1 of the Invention The object of the present invention is to provide a magnetic recording medium having two or more l+M layers having different compositions, including a magnetic layer on a non-magnetic substrate, in the thickness direction between the constituent layers. 100
This is achieved by a magnetic recording medium characterized by providing a transition band between the constituent layer compositions of ~100 OA. In addition, an aspect of the present invention is to prepare a coating material for each constituent layer;
Although the waste may be formed by applying ayet, Wil+11x based on the gas phase tjk product is more effective and has higher productivity, and is therefore preferable. As shown in FIG. 1, the transition zone between the constituent layer compositions referred to in the present invention is the transition zone between the two laminated layers of the layer A having the composition A and the layer BWI having the composition A, and the transition zone between the It compositions Δ and B. It is an overhead in which the content ratio gradually decreases and increases and replaces each other, and more quantitatively, the composition content ratio obtained by the surface analysis (Auger electron spectroscopy) method to find the composition by scraping it into a thin layer in the surface direction is To composition 90w L%, B Jrl composition 10w
t% to AIL j&10II! t%, BAll formation 9
0wt%, the range A- in FIG.
BK! It is I. In this case, the compositional content ratio is a ratio of the amount of essential components involved in the characteristic of interest, and the amount of contaminating components is excluded from the ratio calculation. In the lamination method in which paint is applied, A and B [formed by applying grass debris with paints with significantly different composition ratios] But, or gas phase 1
In the one-layer method, the deposition materials A and B are formed by controlling the evaporation and deposition rate in two energized depositions, and a uniform composition is formed for each differentially thin layer along the surface direction. A structure having a predetermined content ratio gradient in the thickness direction as an accumulation of differentially thin layers can be obtained. Furthermore, as a supplement to the boundary layer, when using the vapor phase deposition method, the deposited layer generally forms a spiral state of unit crystals grown in the shape of a lump with fleas interposed between them. As a result of selecting the size and shape of the crystals and flavours and laminating them, the boundary between the A layer and the 8th layer is a structure in which A and B intersect in a tooth-like manner, and the compositions A and B are formed on the differentially thin layer surface. The structure may have discontinuous mottling, but the average composition content ratio of each differentially thin layer gradually decreases or increases in the thickness direction. No matter which M structure is adopted, if the thickness of the transition zone defined above is 00 to 100 OA, the present invention is added by 4. Figure 2 shows the transition curve of the compositional content ratio in the thickness direction when a cobalt nickel layer is laminated on a chromium layer by the spanter method. In the present invention, the transition/yellow region may be provided between all of the constituent layers, or may be provided only between constituent layers that are particularly effective for the characteristic of interest. Further, as the magnetic material according to the present invention, Fc, Co, old and other magnetic metals, Fc-Roa, Fc-Co, Fc-Roa, Fc-Co,
c-^1. Fc-t4i, Co-Ni, Fe-5i,
Fe-RI+, Fe-V, Fe-Cu, Fe-^u, C
o-Cr. Co-P, Co-V, Co-5iSCo-Yl
Co-La, Co-Cr, Co-1'r, Co-
5+1, Co-Mn, Cor't, Old-Cu, C
o -N i -Fe, Fc-^l-old, Co-old-
^ε, Co-Hl-Cr, Co-Ni-2n, Co-5
i-to1. Fe-5 knee ^1. Hn-B 15Mn-
Alloy magnetic metals such as 3ll, MLI-^e and their oxides (e.g. γ-Fcz01, FezO5, 8a7
x light), etc. Preferably, Co or Co-Ni alloy (Ni content 30wt% or less), or Co-Cr alloy (Cr content 2GwL9j
) below). The magnetic layer thickness may be 0.03 to 0.6 μs. In the first aspect of the present invention, a contact layer, a magnetization auxiliary layer, a protective layer and/or a lubricating layer can be provided. As the contact dust, dimorphous molybdenum or molybdenum carbide containing C, Ct., Ta, Ti, etc. is used, and chromium is mainly used for the magnetization auxiliary layer. Materials for the protective layer that can be applied to this invention) include chromium,
Ilj forms, oxides, nitrides, sulfides, etc. of molybdenum, manganese, vanadium, natanium, aluminum, ronium, platinum, silicon, carbon, or polymeric substances are applied under conditions appropriate to the characteristics of each material. . Furthermore, it is preferable that the material has a high mechanical protection effect, a high abrasion prevention effect, and a high chemical corrosion resistance. Furthermore, in order to enhance the effect of the protective layer, a plurality of layers having different characteristics may be used. Also, the thinner the protective layer is, the better to reduce output spacing loss, but if it is too thin, the protective effect will be lost, so 0.0
1 to 0.15 μl is preferred. A material that provides smoothness, such as carbon, is selected for the lubricating layer. In the present invention, the gas phase 11! is used to form the constituent layers such as the protective layer and the magnetic layer. : It is preferable to apply the deposition method, but as the vapor deposition method, a vacuum evaporation method, a sputtering method, an ion plating method, a chemical vapor deposition method, a facing tarded sputtering method, etc. are used. Also, as a substrate, AI, anodic oxidation? AN with fL film (e.g. alumite treatment), AP with N1-P plating treatment, polyimide, polyaramid, polycarbonate, polyamideimide, polyamide, polyethylene, polyetheretherketone, polyethersulfone, polysulfone, polyetherimide There are plastics such as polytetratyloethylene, polypropylene, etc. Substrates are disc-shaped and film-shaped 4! ? It may be of various types. [Examples] Next, the present invention will be explained with reference to Examples. Example 1 As a nonmagnetic substrate, an aluminum alloy substrate with a thickness of 1.905 μl and 1&1eCA 44 chromium, fluorite nickel, and carbon tarded were placed in a vacuum chamber, and sputtering was performed sequentially to form a magnetic 2-disk sample. The coercive force and squareness ratio were measured. Incidentally, chromium and cobalt-nickel snow <7 talincs were superimposed to ensure the formation of a transition zone. Sputtering conditions: Ultimate vacuum level: 5 x 10-'Torr Argon gas pressure: I x 1O-2Torril
l product j east degree 1608/min magnetization auxiliary tank (chromium layer) 0.35μl transition band 120^ Ja layer (cobalt nickel layer) 0.08μl retention: a layer (carbon layer) 0.02μl Example 2 Example The same layer structure as 1 was given, and the transition band was closed at 975^. Comparative Example 1 A similar layer structure had a transition band of 758. Comparative Example 2 The transition band was 1150^ with a similar layer configuration. The magnetic properties of each medium were evaluated and were as follows.5 Note that each medium has no in-plane magnetic anisotropy. The media used include a hard disk, a 70-noby-day disk, and the like. Further, the effect obtained is not limited to magnetic properties, but is also effective in terms of durability. In the case of a hard disk medium with a carbon layer provided as the top layer, the transition band between the carbon layer and the layer immediately below it, such as a magnetic layer, is the same as in Example 1.2 and Comparative Example 1.2 above. An experiment was conducted on the stability of C3S. As a result, in Example 1.2, the output decrease was less than 10% after 10,000 cssio operations, while in Comparative Example, it was 52%.
,000 times and :13,000 times the output is 10%
decreased. [Effect of the invention 1] By providing a transition zone between the constituent layers, the magnetic properties and durability are improved, which is beneficial not only for the reproducibility of properties but also for quality assurance.

[Brief explanation of the drawing]

FIG. 1 is an explanatory cross-sectional view of a layer structure having a transition band according to the present invention. The PIS2 diagram is a transition curve of the compositional content ratio in the thickness direction selected by surface analysis.

Claims (1)

[Claims] Two magnetic layers having different compositions on a non-magnetic substrate
1. A magnetic recording medium having more than one constituent layer, characterized in that a transition zone between the compositions of the constituent layers of 100 to 1000 Å is provided in the thickness direction between the constituent layers.