CN1008411B - Magnetic recording carrier - Google Patents

Abstract

A magnetic recording medium comprises a non-magnetic substrate and a thin magnetic film, the thin magnetic film being composed mainly of Co, Ni and at least one of Zr and Hf, and a concentration of Zr, Hf or Zr and Hf as contained in the thin magnetic film being 0.1 to 30% by atom on the basis of the total of Co and Ni, and has a considerably higher corrosion resistance than that of the conventional magnetic recording medium having a thin Co-Ni magnetic film.

Description

Magnetic recording carrier

The present invention relates to be used for the magnetic recording medium of device such as disk, particularly have the high record density magnetic recording medium of corrosion resistance and resistance to wear highly reliably.

At the open disclosed a kind of recommended high density magnetic recording that is used for of magnetic recording medium that adopts magnetic metal membrane of № 54-33523 of Japan Patent.In general, magnetic recording medium is made with methods such as evaporation, sputter, spraying plating and ion beam sputterings., proposed in magnetic metal, to add element such as Cr, Nb etc. to more high record density and the more growth of the needs of high reliability along with recently, improved corrosion resistance with this.This is disclosed in open № 57-15406 of Japan Patent and 57-196508.Yet all these prior aries nearly all relate to magnetic recording tape, can't satisfy to resemble the strict demand to reliability such as electronic computer hard disc.

It is the alloy of main component that general disk all adopts with Co and Ni with magnetic recording medium.This magnetic alloy has higher corrosion resistance and significant carrier magnetic properties, and this is because of due to the hexagonal crystalline texture on cobalt alloy surface.But the corrosion resistance of this magnetic alloy in harsher environment is still satisfactory not to the utmost.The open № 60-35326 of Japan Patent has disclosed a kind of magnetic recording media that is made of alloy, and the main component of this alloy is iron, also comprises cobalt, nickel and at least a element of selecting from titanium, zirconium and hafnium.Reduced cost with iron as main component.Though but this alloy includes cobalt, but still has lost the hexagonal crystallizing system, thereby also just lost with the quite high corrosion resistance that magnetic alloy was had and the significant carrier magnetic properties of cobalt as Main Ingredients and Appearance.In addition, obtain high coercive force and also must use the inclination vapor deposition method, rather than conventional vertical vapor deposition method forms magnetosphere.

The purpose of this invention is to provide a kind of magnetic recording medium of being made up of Co-Ni base magnetic metallic film, its corrosion resistance improves and has significant magnetic metal membrane magnetic characteristic.

This purpose and other purpose reach by a kind of magnetic recording medium of non-magnetic substrate and magnetic thin film formed thereon that comprises is provided.This magnetic thin film is mainly by Co, at least a composition among Ni and Zr and the Hf, and this magnetic thin film is 0.1～30% based on the Zr of Co-Ni total amount or the atomic percent of Hf or Zr and Hf.

Fig. 1 is the disk profile of one embodiment of the invention.

Fig. 2 and Fig. 3 are respectively the result curve figure that disk of the present invention and contrast disk are made 1 mol-NaCl spraying and immersion test.

Fig. 4 and Fig. 5 are respectively the magnetic characteristic curve figure of disk of the present invention and contrast disk.

Fig. 6 is the profile of the hard disc carrier of another embodiment of the present invention.

Fig. 7 is the magnetic characteristic curve figure of hard disc carrier shown in Figure 6.

Fig. 8 is the profile of the hard disc carrier of further embodiment of this invention.

Fig. 9 is the composition distribution map of CoNiZr/Cr film by thickness.

Figure 10 is the graph of relation between the Zr content of plane (in-plane) coercive force of disk of the present invention and magnetic thin film.

Figure 11 is a disk S/N(signal to noise ratio of the present invention) and magnetic thin film Ni content between graph of relation.

Figure 12 is the composition distribution map of another embodiment of the present invention by thickness.

Figure 13 and Figure 14 are respectively the result curve figure that disk of the present invention and contrast disk are made 1 mol-NaCl spraying and immersion test.

Figure 15 and Figure 16 are respectively the magnetic characteristic curve figure of disk of the present invention and contrast disk.

Figure 17 is the magnetic characteristic curve figure of further embodiment of this invention.

To with containing respectively periodic table of elements I_b、Ⅲ _a、Ⅳ _a、Ⅴ _aCarried out broad research with the magnetic characteristic of the sputter thin magnetic film of the various Co-Ni alloys target preparation of the 45th, 6 period elements in the VIII family and corrosion resistance etc., found that in the Co-Ni alloy magnetic film and to add at least a among Zr and the Hf, can obtain good effect.

If thin magnetic film contains Zr, then the Zr atomic percent take the Co-Ni total amount as the basis should be 0.1～30%. In order to improve magnetic characteristic, the desired contents take Co as the Ni on basis is 10～60%(atomic percent), more preferably content is 20～50%(atomic percent), ideal content is 30～48%(atomic percent). And, Zr content take the Co-Ni total amount as the basis is as 2～20%(atomic percent) be preferably, comparatively it is desirable to 2～15%(atomic percent), more preferably 3～12%(atomic percent), very it is desirable to 4～11%(atomic percent).

If magnetic thin film contains Hf or Hf and Zr, then should be 0.1～30% atomic percent based on the Hf content of Co-Ni total amount or the total content of Hf and Zr.In the situation that contains Hf and Zr, from being conceived to a large amount of production, be 2～3%(percentage by weight based on the Hf content of Zr) be comparatively desirable.And, be 0.1～15%(atomic percent based on the Hf content of Co-Ni total amount or Hf and Zr total content) be preferably, 2～10%(atomic percent preferably).

Can provide a kind of reading-write performance excellent especially magnetic recording medium according to the present invention.This is by (perhaps when magnetic recording medium uses metallic substrates, make the substrate surface oxidation, thickness reaches 10～400 in magnetic thin film and non-magnetic substrate

) between to form a thickness be 100～5000

The Cr intermediate layer, and magnetic thin film is formed directly on the Cr intermediate layer.

Can provide a kind of magnetic recording medium that is particularly suitable for perpendicular magnetic recording according to the present invention.This is to be 20～1000 by form thickness on substrate surface

Si intermediate layer, C intermediate layer and Ge intermediate layer at least a and realize.And can form a thickness on the magnetic recording medium surface is 100～1000

Non magnetic protective layer, its corrosion resistance is further improved, and has tangible resistance to wear.

Remarkable performance of the present invention is with the following basis that act as.

In the Ar atmosphere of 5 milli torrs, the employing power density is 5W/cm ²Radio frequency sputtering, be to form component on 150 ℃ the substrate of glass to be respectively (Co in temperature _0.7Ni _0.3) _0.9Zr _0.1, (Co _0.8Ni _0.2) _0.8Zr _0.2, (Co _0.9Ni _0.1) _0.7Zr _0.3(Co _0.6Ni _0.4) _0.95Zr _0.05Magnetic thin film.With methods such as lattice difficult to understand (Auger) electron spectroscopy analysis, anodic polarization curves magnetic thin film is analyzed, found under above-mentioned all magnetic thin film surfaces about 60～30

Thickness area in all have high Zr content, and formed fine and close surface oxide layer.

Fig. 9 represents the lattice thickness distribution figure difficult to understand of a typical C oNiZr magnetic thin film.Here, sample is like this preparation: in the Ar atmosphere of 10 milli torrs and power density be 2W/cm ²Condition under, be that to form thickness in 150 ℃ the Si substrate be 5000 in temperature

The Cr lining, subsequently thereon the preparation (Co _0.7Ni _0.3) _0.95Zr _0.05Film.When on magnetic thin film, forming carbon or other non magnetic protective layers, obtain same lattice thickness distribution figure difficult to understand, and in magnetic thin film, do not find nitrogen, oxygen etc.This means that Zr mainly concentrates on magnetic thin film surface and forms the passivation layer of a densification, like this, the corrosion resistance of magnetic thin film be improved significantly.

When Zr content is the 0.1%(atomic percent) or when higher, can obtain above-mentioned effect.On the other hand, because the interpolation of Zr makes the saturation magnetization of magnetic recording medium reduce.But, if be not more than the 30%(atomic percent based on the Zr content of Co-Ni total amount), it is suitable or better that its saturation magnetization is compared with oxide carrier, does not have problems in actual use.

Yet, as specially permit open No56-44752(that is US4306908 in Japan) and IEEE, Trans on Magn, MAG-16(1986) PP1129-1131 is disclosed, adopts rapid quenching technology to be easy to prepare amorphous and CoNiZr alloy than low-coercivity is arranged.The magnetic material that such alloy is used as write head is fit to, but it is not suitable for the magnetic material used as record carrier.On the other hand, discovery is after the body-centered cubic structure of Cr, Mo, elements such as w forms, adopt the CoNiZr magnetic thin film of method preparations such as sputter, evaporation and ion beam sputtering, main crystal structure and magnetic characteristic are suitable for magnetic recording medium, for example, need not to carry out any heat treatment and can obtain 500 oersteds or higher coercive force.That is in 5 milli torr Ar atmosphere, the employing power density is 5W/cm ²Direct current sputtering, be that to form a thickness on 180 ℃ substrate of glass or the Al alloy substrates that applies NiP be 2500 in temperature

The Cr intermediate layer, and to form thickness thereon be 600 Magnetic thin film, it consists of (Co _0.6Ni _0.4) _1-xZ _Rx(X=0,0.02,0.03,0.08,0.11 0.12,0.125,0.15,0.175 and 0.225) here, low Zr content can obtain coercive force up to or be higher than the polycrystal film of 500 oersteds.Yet, when the Zr atomic percentage conc is higher than the 15%(atomic percent) time, film changes amorphous state very soon into, and coercive force is lower than 500 oersteds, as shown in figure 10.If Zr content is at 15～30%(atomic percent) scope in, the CoNiZr magnetic thin film just can crystalization, and, under 280～500 ℃ of temperature, substrate is heat-treated, just can obtain high-coercive force.This means that film can be used as magnetic recording medium when Zr content is in said scope.

In general, applying a layer thickness on as the Al alloy disc of substrate is 5～30 μ m, and the p percentage by weight is 10.5～12% amorphous NiP, can improve its durability, also can improve its surface smoothness and the ability (fliabilitg) that flies.This substrate under 250～300 ℃ of temperature through heat treatment in 3 hours, will crystallization and magnetization, therefore do not heat-treat to good.

For the generation of inhibitory reaction, should just before forming, protective layer carry out such heat treatment.But technology becomes complicated thus.Therefore, obtain the coercive force up to 500 oersteds in order not heat-treat, the Zr atomic percentage conc should be not more than the 15%(atomic percent), as shown in figure 10.In order to strengthen corrosion resistance, the Zr atomic percent should be less than 2%.Improve coercive force with adding Zr, its desired contents is 3～12%(atomic percent), 4～11%(atomic percent) even more ideal, as shown in figure 10.To read in order improving-write performance, for example to rewrite etc., it is essential that magnetic recording medium is made film shape, and, for this purpose, should be greater than the 60%(atomic percent based on the Ni content of Co).On the other hand, in order to improve the packing density of carrier, the coercive force that improves carrier is necessary.For this purpose, be that the desired contents of basic Ni should be 20～50%(atomic percent with Co), 30～48%(atomic percent) even more ideal, as shown in Figure 5.Yet, in order to be used for laterally and perpendicular magnetic recording, be desirable to provide the surface oxide layer or the Si layer of Cr layer, substrate, at least a in C layer and the Ge layer as the intermediate layer.From magnetic characteristic (as coercive force etc.) and production efficiency, the Cr intermediate layer thickness preferably gets 100～5000

, the substrate surface thickness of oxide layer preferably gets 10～400

, and at least a thickness in Si, C and the Ge layer preferably gets 20～1000

In addition, on magnetic thin film, form thickness and be at least 100 Non magnetic protective layer, can improve resistance to wear and corrosion resistance greatly.Yet, when the thickness of non magnetic protective layer surpasses 1000

The time, spacing loss has just increased, and from read-write performance this be disadvantageous.

With the following magnetic thin film of methods analysts such as auger electron spectroscopy and anodic polarization curves:

（Co _0.7Ni _0.3） _0.9Hf _0.1、（Co _0.8Ni _0.2） _0.85Hf _0.15

(Co _0.7Ni _0.3) _0.98(Hf _0.9Zr _0.1) _0.02With

（Co _0.7Ni _0.3） _0.9（Hf _0.02Zr _0.98） _0.1，

They be flow velocity be 20 standard cubic centimeters/minute (SCCM), pressure be 5 the milli torrs Ar atmosphere in, the employing power density is 7W/cm ²Radio frequency sputtering, be to form respectively on 150 ℃ the substrate of glass in temperature, thickness is 500

Analysis result finds, under above-mentioned all magnetic thin film surfaces about 40～80

Thickness area in all have high Hf or Zr content, and formed fine and close oxide layer.In other words, Hf or Zr mainly accumulate in the magnetic thin film surface and form the passivating film of a densification, and the corrosion resistance of magnetic thin film has been improved widely.When the content of Hf or Zr is the 0.1%(atomic percent) or when higher, can obtain this effect.On the other hand, owing to added Hf or Zr and Hf, make the saturation magnetization of magnetic recording medium reduce.But, if be not more than the 30%(atomic percent based on the Hf content of Co-Ni total amount or the content of Hf and Zr), it is suitable or better that its saturation magnetization is compared with oxide carrier, does not have problems in actual use.Yet, read in order to improve-write performance, as rewriteeing etc., it is essential that magnetic recording medium is made film shape.For this purpose, the Ni content based on Co should be 20～40%(atomic percent).And, should be 0.1～15%(atomic percent based on the Hf content of Co-Ni total amount or the content of Hf and Zr).

With reference to Fig. 1 one embodiment of the present of invention are done as detailed below.

Label 11 is the substrates that are made of Al alloy or analog; 12 and 12 ' be the non magnetic coating that constitutes by Ni-P, Ni-W-P or analog; 13 and 13 ' be the intermediate layer that constitutes by Cr or analog; 14 and 14 ' be magnetic thin film by the Co-Ni-Zr alloy composition.The preparation method is as follows;

The external diameter of Al alloy substrates 11 is 130mm, and internal diameter is 40mm, and thickness is 1.9mm.In substrate 11, form thickness and be the non magnetic coating 12 of P-Ni and 12 of 12% percentage by weight of 20 μ m '.Then 5 the milli torrs Ar atmosphere in, 180 ℃ of base reservoir temperatures, power density 4W/cm ²Condition under, radio frequency sputtering thickness is 2500 Cr layer 13 and 13 '.Then, under condition same as described above, with at least a Co among Ti, Zr, V, Nb, Ta, Cr, Mo, W, Ru, Rh, Pd and the Pt as element _0.7Ni _0.3Alloy is made target, and preparation thickness is 600 Magnetic thin film, the atomic percent of element is respectively 0.05%, 0.1%, 1%, 10%, 15%, 20%, 30%, 40% and 50% in the target.

The result of 1 mol NaCl spray testing had wherein represented the recording disc saturation magnetization over time when Fig. 2 represented 40 ℃, and the content based on the element of Co-Ni total amount in this disk is the 10%(atomic percent).Curve 21 is to adopt Co _0.7Ni _0.3The result of the test of the recording disc of magnetic alloy film.This shows, can improve the corrosion resistance of CoNi alloy by adding Ti, Pt, Ru, Ta, Rh, V, Nb, Cr, Zr or Pd, add especially that Zr or Nb can obtain significant corrosion resistance and the reduction of saturation magnetization is very little.In fact, by adding 0.1%(atomic percent at least) element also can obtain same effect.

Moreover the external diameter of Al alloy substrates is 220mm, and thickness is 1.9mm, and it is the 11%(percentage by weight of 15 μ m that thickness is arranged in substrate) the non magnetic coating 12 of P-Ni and 12 '; Under the condition of 150 ℃ of the 10 milli Ar atmosphere of torrs and base reservoir temperatures, be 7W/cm with power density ²Direct current sputtering to form thickness be 1500

Cr intermediate layer 13 and 13 '; Preparing thickness under the same conditions is 500

Magnetic thin film 14 and 14 ', they are to contain the 8%(atomic percent respectively) the Co of Zr, Rh, Nb, Pd, W or V _0.75Ni _0.25Alloy is as target.

When Fig. 3 represented to immerse the disk that obtains in 1 mol-NaCl aqueous solution of 40 ℃, the saturation magnetization of disk over time.As seen from the figure, particularly add Zr corrosion resistance has obviously been strengthened, at this moment magnetic thin film mainly is a polycrystalline structure.As main additive, can obtain this effect with Zr.And, with Zr as element, also can obtain significant corrosion resistance as the quaternary element with Ti, Pt, Ru, Ta, Rh, V, Nb, Cr or Pd.Under the condition of 60 ℃ of temperature, 90% relative humidity and 10000 grades, in test chamber, carry out the corrosion resistance of the magnetic thin film of the following adding additive of temperature/humidity test determination:

At (Co _0.7Ni _0.3) _0.95Zr _0.05,

(Co _0.6Ni _0.4) _0.94Zr _0.06Or

(Co _0.55Ni _0.45) _0.95Zr _0.05In

Add column element (atomic percent) down respectively

0.5 or 1.0% Ru, 1,2 or 5% Ta,

1,2 or 5% Cr, 1,2 or 4% Ti,

2,4 or 6% Nb, 0.2,0.5 or 1.0% Rh,

0.2,0.5 or 1.0% Pt, 0.2,0.5 or 1.0% Pd,

2,4 or 6% V.

Add the decay that the quaternary element can suppress the magnetization of above-mentioned magnetic thin film, make decay after its two week less than 5%, thus particularly useful.It seems that adding the quaternary element makes firmer that the structure of surface oxide layer becomes, and improved the performance of anti-homogeneous corrosion and oxidation.When at least a and its atomic percent in containing the quaternary element is at least 0.01%, can obtain above-mentioned effect.When the 4th elements atomic percentage surpassed 15%, saturation magnetization obviously reduced, and this is undesirable.

With respectively containing the Co that atomic percent is 15% Zr _0.9Ni _0.1, Co _0.6Ni _0.4, Co _0.5Ni _0.5, Co _0.4Ni _0.6, Co _0.3Ni _0.7Or Co _0.62Ni _0.3Cr _0.08As alloys target, preparation thickness is 2000 in substrate Cr intermediate layer and thickness be 700 Magnetic thin film.In this situation, obtained and above-mentioned two effects that embodiment is identical with the way of adding Zr, and added the Zr atomic percent and be not less than at 0.1% o'clock, corrosion resistance has been improved significantly.But add the Zr atomic percent greater than 30% o'clock, saturation magnetization and coercive force all obviously reduce.In other words, in fact the atomic percent of not wishing Zr is greater than 30%, and it is desirable that the Zr atomic percent is not more than 30%.

Fig. 4 represents the coercive force of disk shown in Figure 2, and coercive force and coercive force rectangle degree be respectively greater than 600 oersteds and 0.8, contains except the disk of Pd.And except that the disk that contains Pd, all disks all have good reading-write performance.

Fig. 5 represents the coercive force of following magnetic thin film and based on the relation curve between the Ni content of Co.This is to be 1000 at thickness

The Cr intermediate layer on the thickness that forms be 600

The Co-Ni magnetic thin film, and to contain atomic percent be 12% Zr.It is in the Ar atmosphere of 7 milli torrs, is 8W/cm with power density ²Magnetron direct current sputtering preparation.When the Ni content based on Co is 10～60%(atomic percent) time, the required plane coercive force that is higher than about 550 oersteds of high density recording just can be obtained.When the atomic percent of Ni is 20～50%, can obtain higher packing density.In fact, adopting slit width is the ferrite toroidal magnetic head of 0.4 μ m, when flying height is 0.25 μ m, just can obtain to be higher than the high record density of 20,000 magnetic fluxs parameter/inch (KFCI).In Fig. 5, when the Ni content based on Co is 20～50%(atomic percent) time, just can obtain to be higher than the higher coercivity of 650 oersteds.The Ni atomic percent is 30～48% o'clock, can obtain to be higher than the more high-coercive force of 750 oersteds.Therefore, from reading-write performance, such Ni content range is desirable.

For example, be that 130mm, thickness are that to apply a layer thickness on the Al alloy substrates 11 of 1.9mm be the 11.5%(percentage by weight of 20 μ m at diameter) P-Ni.Then, use Al ₂O ₃Or diamond abrasive grinds and polishes magnetic disk surface, and obtaining surface roughness with this is 60 (Ra) even loop configuration.Like this, non magnetic coating 12 and 12 ' thickness are reduced to 15 μ m.In the Ar atmosphere of 15 milli torrs, 200 ℃ of base reservoir temperatures and power density 1W/cm ²Condition under, forming thickness on non magnetic coating is 3000

Cr intermediate layer 13 and 13 '.Then, under condition same as described above, Cr intermediate layer 13 and 13 ' on the preparation thickness be 600

Magnetic thin film 14 and 14 ', it consists of (Co _1-xNi _x) _0.955Zr _0.045(X=0.2,0.25,0.3,0.37,0.40,0.45,0.48 or 0.50).Then, in the Ar atmosphere of 3 milli torrs, power density 8W/cm ²Condition under, forming thickness on magnetic thin film is 450 Non magnetic C cover layer.Forming a layer thickness at last is 40

The transparent lubricating film of perfluoroalkyl polyethers (Perfluoroalkyether), thereby finish the manufacturing of disk.With slit width is that the film magnetic head of 0.4 μ m is measured reading-write performance of disk.As shown in figure 11, when the Ni content based on Co is 30～48%(atomic percent) time, can obtain high signal to noise ratio (S/N).In other words, can obtain excellent reading-write performance.

In the above-described embodiments, when magnetic thin film directly forms, only can obtain the plane coercive force of about 50 oersteds on the NiP coating.And be 100 at thickness

Or form magnetic thin film on the thicker Cr intermediate layer, can obtain good plane coercive force.Yet the Cr intermediate layer thickness is greater than 5000

The time obtainable coercive force be not higher than the Cr intermediate layer thickness less than 5000

The time obtainable coercive force.From production efficiency, the thickness in Cr intermediate layer should be greater than 5000 , preferably be not more than 3000

On Al alloy substrates 11, have thickness be 25 μ m Ni- W-P coating 12 and 12 '.In the Ar atmosphere of 5 milli torrs, 100 ℃ of base reservoir temperatures and power density 4W/cm ²Condition under, forming thickness on the Ni-W-P coating is 100 C intermediate layer 13 and 13 '.Under identical condition, form (the Co that thickness is 0.2 μ m more thereon _0.6Ni _0.4) _0.8Zr _0.2Magnetic thin film 14 and 14 '.Thereby can obtain a recording disc with good corrosion resistance and perpendicular recording characteristic.Adopting thickness is 200 Si intermediate layer or thickness be 50 The Ge intermediate layer also can obtain identical effect.Furtherly, when the intermediate layer be 20

Or when thicker, can obtain this effect.But, in fact desirable thickness is to be not more than 1000

Fig. 6 provides the present invention and is different from another embodiment shown in Figure 1.The substrate 61 that it is made of Al alloy or analog, non magnetic coating 62 and 62 ' and the magnetic thin film 63 and 63 that constitutes by Co-Ni-Zr ' form.

Be that on Al alloy substrates 61 surfaces of 90mm thickness to be arranged be the 11.5%(percentage by weight of 15 μ m at external diameter) the non magnetic coating 62 of Pt-Ni and 62 '.Containing the 20%(percent by volume) O ₂The Ar atmosphere of 5 milli torrs in, with 100 ℃ of base reservoir temperatures and power density 0.4W/cm ²Condition reactive sputtering corrosion is carried out in substrate, forming the degree of depth with this on two surfaces up and down is 30

Surface oxide layer.Then, in the Ar atmosphere of 5 milli torrs, at 150 ℃ of base reservoir temperatures and power density 6W/cm ²Condition under, with containing the Co-Ni alloys target that atomic percent is 5,10 or 15% Zr, preparation thickness is 600 Magnetic thin film 63 and 63 '.

Fig. 7 represent the Zr content based on the Co-Ni total amount be atomic percent 10% magnetic thin film saturation flux density and based on the relation curve between the Ni content of Co.As seen from the figure, when the Ni atomic percent is not more than 50%, can obtain satisfied saturation flux density, and can obtain same level as shown in Figure 5 the plane coercive force and with identical well the reading of those recording discs shown in Figure 1-write performance.And find that its corrosion resistance is poorer slightly than recording disc shown in Figure 1, but be no problem in practicality.

Be formed on by the NiP coating on the oxide layer that the reactive sputtering corrosion obtains if magnetic thin film is the Cr intermediate layer by as shown in Figure 1, then can obtain the most excellent reading-write performance.

Among other embodiment outside the foregoing description, containing O ₂Ar atmosphere in prepare magnetic thin film, thereby obtain to have the recording disc that oxygen atom percentage is 0.1～15% magnetic thin film.Figure 12 represents, forms the representative instance that distributes with thickness (lattice thickness section difficult to understand) according to recording disc of the present invention.In the present embodiment, do not observe other elements, as nitrogen etc.Although there are some shortcomings, as saturation magnetization reduce and corrosion resistance also poor slightly, recording disc in the reality use without any problem.

For example, at external diameter the P-Ni of surface-coated one deck 11% percentage by weight of the Al alloy substrates 11 of 130mm, use Al ₂O ₃Or diamond abrasive with substrate grind, polishing, obtaining surface roughness is 70

Even loop configuration.Like this, just on the surface of substrate 11, form thickness and be the non magnetic coating 12 of 10 μ m and 12 '.Then, be 2500 at thickness

Cr intermediate layer 13 and 13 ' on to prepare thickness be 600

Magnetic thin film 14 and 14 ', it is composed as follows:

（Co _0.7Ni _0.3） _0.95Zr _0.05，（Co _0.7Ni _0.3） _0.94Zr _0.06，

（Co _0.65Ni _0.35） _0.94Zr _0.06，（Co _0.60Ni _0.40） _0.94Zr _0.06，

（Co _0.7Ni _0.3） _0.945Zr _0.05Ru _0.005，

(Co _0.6Ni _0.4) _0.91Zr _0.05Ta _0.04Or

（Co _0.7Ni _0.3） _0.9Zr _0.05Mo _0.05

And contain atomic percent and be respectively 0,5,7,10 or 15% oxygen.Then, forming thickness on the magnetic thin film surface is 400

C, B ₄C or SiO ₂Protective layer.At last, in protective layer surface-coated thick 50

The transparent lubricating film of perfluoroalkyl polyethers.The making of recording disc has just been finished like this.

Reading-write performance of the recording disc that utilizes a film magnetic head to measure to make, this magnetic head gap is wide to be 0.7 μ m, relative velocity is 13.5m/S, and flying height is that 0.22 μ m finds that output signal reduces with the increase of oxygen content, and carrier noise ratio output signal reduces manyly.Therefore, the signal to noise ratio of carrier (S/N) has improved with the increase of oxygen content on the contrary.This is because oxygen and Zr effectively combine on crystal boundary and make intercrystalline magnetic interaction weaken and with the increase of oxygen content, the limited proportionality of writing down between the bit narrows down.When the atomic percent of oxygen greater than 15% the time, output signal obviously reduces, with regard to magnetic head-carrier system, overall signal to noise ratio (S/N) is quite low, therefore, the atomic percent of oxygen should be greater than 15%.

In the Ar atmosphere of 5 milli torrs, at 150 ℃ of base reservoir temperatures and power density 8W/cm ²Condition under, on the recording disc surface of the Fig. 1 or the embodiment of the invention shown in Figure 6, be 500 with dc magnetron sputtering thickness

The C layer.Magnetic recording medium with such C layer even also do not change, and finds that corrosion resistance has obviously improved after the oxidation more than 8 hours in corrosion test as shown in Figure 3.But also the durability of finding it is higher by 10 than the recording disc that does not have the C layer ¹～10 ⁵Doubly.Therefore, also be desirable with regard to durability preparation C layer.With regard to protective layer thickness, 100

Or thicker, just can obtain above-mentioned effect.But its thickness is greater than 1000

The time, read-write performance significantly reduces.Therefore, protective layer thickness is greater than 1000

Be actually worthless.When adopting B, BN or SiC protective layer or oxidation magnetic thin film surface all can obtain same effect.Apply organic lubricating film on protective layer, durability further increases by 2～3 times.

Fig. 8 represents another embodiment, the 81st, and the surface is through the Al substrate or the polyimides (Polyimide) of hard alumina membrane processing (alumilite), at the bottom of the organic group of PETG (PET) or analog; 82 and 82 ' be intermediate layer same as shown in Figure 1; 83 and 83 ' be the Co-Ni-Zr magnetic thin film; 84 and 84 ' be non magnetic protective layer same as described above.Their composition, the preparation process of the thickness of film or layer and film or layer is all same as described above.

In the above-described embodiment, soft, hard disc carrier are described, but the effect of having described till now of the present invention not only can obtain at these carriers, and also can obtain at the tape carrier by means of example.In addition, the not only available sputtering method preparation of these films or layer also can be adopted methods such as evaporation, ion beam sputtering.

The embodiment that below detailed description is contained the magnetic thin film of Hf.

Preparation thickness is 600 under the condition identical with test piece shown in Figure 2

Magnetic thin film, use and to contain the Co that atomic percent is 0.05,0.1,1,5,10,15 20 or 25% Ti, Zr, V, Nb, Ta, Cr, Mo, W, Ru Rh, Pd, Pt or Hf respectively _0.7Ni _0.3Alloys target.

Figure 13 is illustrated in 40 ℃ when making 1 mol-NaCl aqueous solution spray testing, based on the atomic percent of the element of Co-Ni total amount be 10% disk saturation magnetization over time.Curve 131 is to use Co _0.7Ni _0.3The result that the disk of alloy magnetic film obtains.As seen from the figure, interpolation Hf, Zr or Nb can make saturation magnetization not reduce and obtain good corrosion resistance.The atomic percent of also finding Hf, Zr or Nb is 0.1% or when higher, just can actually obtain this effect.

At external diameter is that 220mm, thickness are on the surface of Al alloy substrates 11 of 1.9mm, form thickness and be the non magnetic coating 12 of Ni-11Wt%P and 12 of 15 μ m '.Being in the 10 milli torr Ar atmosphere of 20 standard cubic centimeters/minute (SCCM) in airflow rate then, is 7W/cm with 150 ℃ of base reservoir temperatures and direct current power density ²Condition, the preparation thickness be 1500 The Cr intermediate layer.Use the Co that contains Hf, Zr, Rh, Nb, Pd, W or the V of 8% atomic percent respectively according to condition same as described above _0.75Ni _0.25It is 500 that alloys target prepares thickness

Magnetic thin film.

Figure 14 represents that saturation magnetization over time when the recording disc of making like this immerses in 1 mol-NaCl aqueous solution.When particularly containing Hf and Zr, corrosion resistance obviously increases.At this moment all magnetic thin films all mainly are polycrystalline structure.

Forming thickness is 2000

Cr intermediate layer and thickness be 700

Magnetic thin film the time, use following alloys target: the Co that contains atomic percent respectively and be 9% Hf _0.9Ni _0.1, Co _0.6Ni _0.4, Co _0.4Ni _0.6Or Co _0.62Ni _0.3Cr _0.08At this moment, can obtain and above-mentioned two effects that embodiment is identical owing to having added Hf.And the atomic percent that adds Hf is not less than at 0.1% o'clock, and corrosion resistance obviously improves.Yet, when the atomic percent that adds Hf greater than 30% the time, coercive force and saturation magnetization obviously reduce.Like this, the atomic percent that adds Hf is actually worthless greater than 30%, finds that the addition preferably of Hf is that atomic percent is not more than 15%.

Figure 15 represents the plane coercive force of disk shown in Figure 13.Wherein, except that the disk that contains Pd, the plane coercive force of all disks is all greater than 600 oersteds, and good reading-write performance is arranged.The disk that contains Hf, Zr or Nb can obtain high plane and rectify stupid rectangle degree, rectifying stupid rectangle degree for the disk plane that contains Hf, Zr and Nb is respectively 0.94,0.94 and 0.930, the plane of containing the disk of Ta, Cr, Ru, Rh or Pt is rectified stupid rectangle degree and is about 0.92, and the disk that contains Ti, V, Mo or W is about 0.90.Such level is no problem for practical application.On the other hand, it is quite low that stupid rectangle degree is rectified on the plane of containing the disk of Pd, and as 0.45, it is not suitable for use in record carrier.

Figure 16 represents the plane coercive force and based on the relation curve between the Ni content of Co.This is to be 1000 in the Ar atmosphere of 7 milli torrs, at thickness

The Cr intermediate layer on, use power density 8W/cm ²Dc magnetron sputtering thickness be 600 , containing Hf is the Co-Ni magnetic thin film of 20% atomic percent.Here, when the Ni atomic percent based on Co is 10～60%, can obtain the plane coercive force greater than 550 oersteds, this is essential for high density magnetic recording.When the Ni atomic percent based on Co is 20～50%, be 2～10% o'clock based on the Hf atomic percent of Co-Ni total amount, can obtain higher packing density.The magnetic thin film that replaces Hf with Zr can obtain same effect.In fact, be that 0.4 μ m, flying height are the packing density that the manganese-zinc ferrite magnetic head of 0.28 μ m can obtain to be higher than the logical number/inch (FCI) of 20% magnetic variation with slit width.

In above embodiment, when magnetic thin film is formed directly on the Ni-P coating of substrate, only obtain the coercive force of about 50 oersteds.But, be not less than 100 at thickness

The Cr intermediate layer on form magnetic thin film, can obtain practical enough coercive forces of.Yet, aspect the increase coercive force, even the Cr intermediate layer thickness is greater than 5000

Its effect also unlike thickness less than 5000

The time how much progress arranged.Therefore, the viewpoint Cr intermediate layer thickness from production efficiency should not surpass 5000 , preferably be no more than 3000

In 5 milli torr Ar atmosphere, on the Ni-W-P of 100 ℃ aluminum alloy substrate 11 coating, use power density 4W/cm ²It is 10 that sputter forms thickness

The carbon intermediate layer.Prepare (the Co that thickness is 0.2 μ m then thereon _0.6Ni _0.4) _0.91Hf _0.09Magnetic thin film 14 and 14 ', thus acquisition has the magnetic recording medium of good corrosion resistance and perpendicular magnetic recording charact.Adopting thickness is 50

Si intermediate layer or thickness be 90

The Ge intermediate layer also can obtain same result.Thickness is not less than 5 when the intermediate layer

The time, promptly can be observed the intermediate layer effect.Yet thickness satisfied in the practicality should be not more than 100

The recording disc of structure shown in Figure 6 adopts method preparation same as described above, and just magnetic thin film contains Zr and Hf simultaneously.That is, with containing the 4%(atomic percent) Zr and 5,10 or the 15%(atomic percent) to prepare thickness be 600 for the Co-Ni alloys target of Hf

Magnetic thin film.

Figure 17 represent to contain atomic percent based on the Co-Ni total amount be 5% Hf and 40% Zr magnetic thin film saturation flux density and based on the relation curve between the Ni content of Co.As seen from the figure, be not more than at 50% o'clock, can obtain the practical satisfied saturation flux density that, can also obtain the plane coercive force of same level as shown in figure 16 and well read-write performance identical with recording disc shown in Figure 1 at the atomic percent of Ni.In addition, find that corrosion resistance is poorer slightly than recording disc shown in Figure 1, but no problem with regard to realistic scale.

With above-mentioned different another embodiment, containing O ₂Ar atmosphere in prepare magnetic thin film, obtain having with this and contain the recording disc that oxygen atom percentage is 0.1～15% magnetic thin film.Although there are some shortcomings, i.e. saturation magnetization decline and corrosion resistance are poor slightly, and this recording disc is without any problem in practicality.

In the Ar atmosphere of 5 milli torrs, with 150 ℃ of base reservoir temperatures and power density 8W/cm ²Condition, on the recording disc surface of the Fig. 1 or the embodiment of the invention shown in Figure 6, be 400 with dc magnetron sputtering thickness

The C protective layer.Through the corrosion test more than 8 hours (shown in Figure 14) afterwards, the magnetization of this magnetic recording medium does not change, and finds that its corrosion resistance has significantly improved.And, find that also its durability is higher by 10 than the recording disc that does not have the C protective layer ¹～10 ⁴Doubly.Therefore, with regard to durability, also wish preparation C protective layer.Protective layer thickness is 100 Or thicklyer just can observe above-mentioned effect, still, when thickness greater than 1000 The time, then read-write performance obviously becomes bad.Therefore, the thickness reality of protective layer should be greater than 1000 Adopt B, B-15at%C or SiC protective layer or make the magnetic thin film surface oxidation, also can observe identical effect.Apply the organic substance lubricating layer on protective layer, durability can further improve 2 or 3 times.

Claims (24)

1, a kind of magnetic recording medium comprises a non-magnetic substrate and one deck magnetic thin film formed thereon, and this thin magnetic layer mainly is made up of Co and Ni, it is characterized in that:

The thin magnetic layer (14,14 '; 63,63 '; 83,83 ') comprise Zr, its atomic percent based on the Co-Ni total amount is 0.1～30%, Zr mainly be distributed in the thin magnetic layer (14,14 '; 63,63 '; 83,83 ') near surface.

2, magnetic recording medium as claimed in claim 1 is characterized in that: the Zr content based on the total amount of Co and Ni is 2～20% atomic percents.

3, magnetic recording medium as claimed in claim 1 is characterized in that: the Ni content based on Co is 10～60% atomic percents.

4, magnetic recording medium as claimed in claim 1 is characterized in that: the Ni content based on Co is 20～50% atomic percents, is 2～20% atomic percents based on the Zr content of the total amount of Co and Ni.

5, magnetic recording medium as claimed in claim 1 is characterized in that: the thin magnetic layer (14,14 '; 63,63 '; 83,83 ') at least a element among Ti, Pt, Ru, Ta, Rh, V, Nb, Cr and the Pd except that Co, Ni and Zr, also comprised; Its total amount is 0.01～15% atomic percent.

6, magnetic recording medium as claimed in claim 1 is characterized in that; The oxygen atom percentage that thin magnetic layer (63,63 ') comprises is 0.1～15%.

7, magnetic recording medium as claimed in claim 1 is characterized in that: in non-magnetic substrate (11; 81) and the thin magnetic layer (14,14 '; 83,83 ') between have a layer thickness be 10～500 millimicrons the Cr intermediate layer (13,13 '; 82,82 ').

8, magnetic recording medium as claimed in claim 1 is characterized in that: non-magnetic substrate 11 is the oxidized nonmagnetic metal dish in surface, and the thickness of oxidation is 1 to 40 millimicron.

9, magnetic recording medium as claimed in claim 1 is characterized in that: laminated magnetic film (14,14 '; 83,83 ') be perpendicular magnetic recording layer, and in non-magnetic substrate (11; 81) and the thin magnetic layer (14,14 '; 83,83 ') between at least a intermediate layer in Si intermediate layer, C intermediate layer or the Ge intermediate layer is arranged, its thickness is 2 to 100 millimicrons.

10, magnetic recording medium as claimed in claim 1 is characterized in that: be formed with thickness and be 10 to 100 millimicrons non magnetic protective layer (84,84 ') on the surface of thin magnetic layer (83,83 ').

11, magnetic recording medium as claimed in claim 1 is characterized in that: non-magnetic substrate (11; 61; 81) be the Al alloy that is coated with NiP or NiWP.

12, a kind of magnetic recording medium comprises a non-magnetic substrate and one deck magnetic thin film formed thereon, and this magnetic thin film is made up of Co and Ni substantially, it is characterized in that: this thin magnetic layer (14,14 '; 63,63 '; 83,83 ') the Hf content that comprises based on the total amount of Co and Ni is 0.1 to 30% atomic percent.

13, magnetic recording medium as claimed in claim 12 is characterized in that: the Ni content based on Co is the percentage of 10 to 60% atoms.

14, magnetic recording medium as claimed in claim 12 is characterized in that: in non-magnetic substrate (11; 81) and the thin magnetic layer (14,14 '; 83,83 ') between have a thickness be 10 to 500 millimicrons the Cr intermediate layer (13,13 '; 82,82 ').

15, magnetic recording medium as claimed in claim 12 is characterized in that: non-magnetic substrate (11) is the nonmagnetic metal substrate, and its oxidized thickness in surface is 1 to 40 millimicron.

16, magnetic recording medium as claimed in claim 12 is characterized in that: in non-magnetic substrate (11; 81) and the thin magnetic layer (14,14 '; 83,83 ') between provide at least a layer thickness be 0.5 to 10 millimicron Si intermediate layer, C intermediate layer or Ge intermediate layer (13,13 '; 82,82 ').

17, magnetic recording medium as claimed in claim 12 is characterized in that: be formed with thickness and be 10 to 100 millimicrons non magnetic protective layer (84,84 ') on the surface of thin magnetic layer (83,83 ').

18, a kind of magnetic recording medium comprises a non-magnetic substrate and one deck thin magnetic layer formed thereon, and this thin magnetic layer mainly is made up of Co and Ni, it is characterized in that:

The thin magnetic layer (14,14 '; 63,63 '; 83,83 ') comprise Hf and Zr, its atomic percent based on the total amount of Co and Ni is 0.1 to 30%, Hf and Zr mainly be distributed in the thin magnetic layer (14,14 '; 63,63 '; 83,83 ') near surface.

19, magnetic recording medium as claimed in claim 18 is characterized in that: the Ni content based on Co is 10 to 60% atomic percents.

20, magnetic recording medium as claimed in claim 18 is characterized in that: the Ni content based on Co is 20 to 50% atomic percents, is 0.1 to 15% atomic percent based on the Hf of the total amount of Co and Ni and the content of Zr.

21, magnetic recording medium as claimed in claim 18 is characterized in that: in non-magnetic substrate (11; 18) and thin magnetic layer (14,14; 83,83 ') between have a layer thickness be 10 to 500 millimicrons the Cr intermediate layer (13,13 '; 82,82 ').

22, magnetic recording medium as claimed in claim 18 is characterized in that: non-magnetic substrate (11) is a nonmagnetic metal substrate, and the thickness of its surface oxidation is 1 to 40 millimicron.

23, magnetic recording medium as claimed in claim 18 is characterized in that: in non-magnetic substrate (11; Thin magnetic layer 81) (14,14 '; 83,83 ') between have at least a layer thickness be 0.5 to 10 millimicron Si intermediate layer, C intermediate layer or Ge intermediate layer (13,13 '; 82,82 ').

24, magnetic recording medium as claimed in claim 18 is characterized in that: be formed with a layer thickness and be 10 to 100 millimicrons non magnetic protective layer (84,84 ') on the surface of thin magnetic layer (83,83 ').

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