Background technology
In the development and application of digital image, utilizing PC to obtain quantity of information increases day by day.Along with the increase of quantity of information, need that the recorded information capacity is big, low price and record short magnetic recording medium readout time.
Retract in the type magnetic recording medium in high density recording mediums such as hard disk or ZIP high capacity such as (iomega corp's productions), comparing information recording area with soft disk is made of narrow magnetic track, for in narrow track width scope correctly scanning head carry out signal record and regeneration with high S/N ratio, must use the tracking servo technology correctly to scan.
So, at hard disc, retract in this class high capacity magnetic recording medium of type magnetic recording medium, corresponding disk is in 1 week, adopt certain angle to be arranged at intervals with zones such as record tracking servo signal, address information signal, regeneration timing signal, adopt the magnetic head mode of these signals of regenerating at certain intervals, on magnetic track, scan while confirm, proofread and correct head position.These signals are recorded in recording medium top when making magnetic recording medium, this method is called preformatting.
Owing to when records such as tracking servo signal, address signal, regeneration timing signal, require to determine the precision height of position, so, behind the magnetic track, use special-purpose servo pen recorder to carry out the preformat record in magnetic recording medium, arranging by the magnetic head of location-controlled.
Therefore, utilizing magnetic head servosignal, address signal, regeneration timing signal to be carried out in the preformat record, closely magnetic head being carried out position control carries out record on one side on one side in order to use the dedicated servo pen recorder, just needs the more time in the preformat record.Along with magnetic recording density increases, during the preformat record signal quantitative change many, just need more time.Therefore, in magnetic recording medium was made, the required expense of preformat recording process such as servosignal accounted for larger specific gravity in manufacturing cost, so hope can reduce the cost of this technology.
Someone proposes to not be used in each magnetic track record preformat and adopts from main carrier preformat magnetic is replicated in mode on the subordinate recording medium.For example, the spy opens clear 63-183623 communique, the spy opens flat 10-40544 communique and the special reproduction technology of opening flat 10-269566 communique introduction.
Open in clear 63-183623 communique or the special method of opening flat 10-40544 communique record the spy, as main carrier for magnetic copying, on substrate surface, be formed with convex-concave shape corresponding to information signal, at least form strong magnetic film on the protuberance surface of convex-concave shape, the surface that the magntic duplication master is carried contacts with sheet or plate-like magnetic recording medium surface, be formed with strong magnetic film or ferromagnetism powder coating layer on this magnetic recording medium surface, perhaps affix AC bias magnetic field or D.C. magnetic field again, the strong magnetic material that constitutes the protuberance surface is excited, just can corresponding with the convex-concave shape magnetizing pattern be recorded on the magnetic recording medium.
In this method, magnetic recording medium subordinate medium during main carrier for magnetic copying protuberance surface and preformatting connect airtight, simultaneously, the strong magnetic material that constitutes protuberance is excited, so, be the clone method that on the subordinate medium, forms the preformat information record of regulation, the relative position that can make main carrier for magnetic copying and subordinate medium does not change and carries out record quietly, can carry out correct preformat record, and the record required time is also extremely short.
Because this magnetic duplicating method is the copy mode that main carrier for magnetic copying is contacted with static state with the subordinate medium, main carrier for magnetic copying, the damage of subordinate medium are lacked in the recorded servo signal operation, are the high copy modes of being expected of durability.
Be used in magnetic and duplicate that magnetic in the main carrier is general to use soft magnetic material.In order to improve this class magnetic duplicating efficiency, consider that little, saturated in the little magnetic field magnetosphere in anisotropy magnetic field (Hk) is better, so, to Hk<8.0 * 10
-2The material of kA/m (1Oe) is checked.But, adopt Hk<8.0 * 10
-2The magnetosphere of KA/m (1Oe) carries out in the medium that magnetic duplicates, can cause that magnetic reproduced output signal and full width at half maximum change and change other phenomenon of signal level.In case it is big that the anisotropy magnetic field (Hk) of main carrier becomes, the magnetic reproducing signals is just not obvious, produces the problem that output signal dies down.
Embodiment
In the magnetic of recorded information duplicates, generally use soft magnetic material as main carrier for magnetic copying.Particularly in order to improve duplicating efficiency, can consider to use the magnetic anomaly tropism little, in little magnetic field saturated magnetosphere.
At this, at the magnetic anomaly tropism Hk that uses less than 8.0 * 10
-2During kA/m (1Oe), under the state that main carrier for magnetic copying and subordinate medium connect airtight, even also can be in low-intensity magnetic field the magnetosphere magnetic saturation on the main carrier for magnetic copying.Therefore, in about 30A/m earth magnetism or electromagnet iron core residual magnetization magnetic field, the magnetization of the magnetosphere of main carrier for magnetic copying is saturated, and the subordinate medium magnetized state beyond the recorded information part changes, and the phenomenon that the signal rank descends can occur.
Before reaching magnetic saturation, need the time, have in use under the situation of the magnetospheric main carrier for magnetic copying of high magnetic anomaly tropism, in case complementary field under main carrier for magnetic copying and the subordinate medium tightlock status, should can leak on the subordinate medium by the magnetic field that the magnetosphere on the main carrier for magnetic copying absorbs, can cause that also the subordinate medium magnetized state of recorded information figure changes and reduces and export.
According to this analysis result, the size of the anisotropy magnetic field H k of main carrier for magnetic copying and the relation of subordinate medium coercive force Hc are studied in great detail, the result shows, concerns 4 * 10 satisfying
-4<(Hk/Hc)<2 * 10
-1Under the condition, adopt magnetic duplicating method can prevent significantly that the tracer signal rank from descending.
The present invention is being connected airtight in magnetic recording medium carries out magnetic duplicating method that magnetic duplicates main carrier for magnetic copying and subordinate medium, provide the anisotropy magnetic field (Hk) that can make main carrier for magnetic copying corresponding the pass of subordinate medium coercive force (Hc) be 4 * 10
-4<(Hk/Hc)<2 * 10
-1
The main carrier for magnetic copying that uses in magnetic duplicating method of the present invention can adopt following method to make.
As the substrate of main carrier for magnetic copying, can use ganoid material silicon, aluminium, glass, synthetic resin etc.
At first, painting photoresist film on these substrates duplicates at magnetic on the figure of formation suitable diaphragm figure is carried out the figure exposure, or directly forms.
Under the situation of figure exposure, according to reactive etching or utilize physical property etchings such as argon plasma or liquid to be etched in to form figure on the substrate.
Secondly, the part in regulation forms magnetosphere with the thickness spatter film forming of stipulating.Subsequently, mention and remove photoresist film.When magnetic duplicates, contact, also can adopt the photofabrication facture to make convex magnetosphere body with the subordinate medium.
Also can use injection molding method as fine machining method.
Illustrate with injection molding method, rotate the glass plate be coated with photoresist film on one side, the laser that corresponding on one side servosignal irradiation regulates is the photoresist film exposure on the whole glass.This resist film develops, and the glass substrate of development is in formation convex-concave on glass.Then, remove resist film, the enterprising electroplating of glass substrate forming convex-concave is made into the former dish of the plating with convex-concave.
As the electroplate material, can use nickel or nickel alloy.In order to improve the durability of electroplating former dish, also can adopt formation diamond-like carbon element films such as sputter.
According to the injection molding method of electroplating former dish, make the resin substrate that is formed with figure.Can use acryl resins such as polycarbonate, polymerthyl acrylate as resin material, vestolits such as Polyvinylchloride chloroethylene copolymer, epoxy resin, non-lattice Polyolefin and polyester etc.From aspects such as moisture-proof, big or small stability and prices, polycarbonate is best.Under the situation of flash on the electroplated discs that forms, adopt polishing or polishing to remove.The gash depth of figure can be preferably in the 200-500nm scope in the 50-1000nm scope.
As magnetic material, can use Co, Co alloy (CONi, CoNiZr, CoNbTaZr etc.), Fe, Fe alloy (FeCo, FeCoNi, FeNiMo, FeAlSi, FeAl, FeTaN), Ni, Ni alloy (NiFe), preferably use FeCo, FeCoNi.Before the magnetosphere of the main carrier for magnetic copying that uses in the magnetic duplicating method of the present invention forms, non magnetic basic unit can be set, preferably make basic unit's crystalline network and grating constant be suitable for magnetosphere.
As what the material that forms basic unit can be enumerated Cr, CrTi, CoCr, CrTa, CrMo, NiAl, Ru etc. are arranged.
Input electric power was regulated when magnetospheric anisotropy magnetic field (Hk) can be according to magnetic material, sputtering pressure, the sputter of making temperature.Also can be according to d.c. sputtering, exchange use-pattern variation in the sputter such as sputter etc. and regulate.
Diamond-like carbon element diaphragms such as (DLC) also can be set on magnetosphere, lubricant layer can also be set.
Particularly as diaphragm, preferably 5-30nm diamond-like carbon element film and lubricant.
There is lubricant, in main carrier for magnetic copying and subordinate medium contact process, timing carried out in the skew that produces,, also can not reduce durability even rub.
Below, the subordinate medium that the present invention is used describe.
As the subordinate medium, the magnetic recording medium of enumerating has Zip (iomega corp) with recording medium Zip100, Zip250 or be called high density floppy disk of HiFD etc.
The coercive force Hc of subordinate medium can be greater than 103kA/m (1300Oe), less than 313kA/m (4000Oe).More preferably greater than 127kA/m (1600Oe), less than 239kA/m (3000Oe).Can not keep 1Gb/6.45cm during the coercive force Hc of subordinate medium is not enough 103kA/m
2The high density recording information that (1 gigabit/1 square inch) is above.When the enterprising line item of subordinate medium, may be difficult to make the magnetic recording head holding position during on the contrary, greater than 313kA/m.
For metal foil membranous type magnetic recording medium, may use Co, Co alloy (CoPtCr, CoCr, CoPtCrTa, CoPtCrNbTa, CoCrB, CoNi etc.), Fe, Fe alloy (FeCo, FePt, FeCoNi) as magnetic material.In order clearly to duplicate, preferably magnetic flux density is big, and with the magnetosphere equidirectional of main carrier for magnetic copying in have the magnetic anomaly tropism, be direction in the face when promptly in face, writing down, be vertical direction during perpendicular recording.
In order to be that substrate-side forms necessary magnetic anomaly tropism non magnetic basic unit is set in the magnetosphere bottom, make its crystalline network and grating constant and magnetosphere suitable.
Specifically, as what base material can be enumerated Cr, CrTi, CoCr, CrTa, CrMo, Ni, Ru etc. are arranged.
The anisotropy magnetic field (Hk) of main carrier for magnetic copying of the present invention can be 4 * 10 with the relation of subordinate medium coercive force (Hc)
-4<(Hk/Hc)<2 * 10
-1, be preferably 4 * 10
-3<(Hk/Hc)<1.5 * 10
-1
Embodiment
Below with embodiment the present invention is described.
Embodiment 1
3.5 as substrate, the magnetosphere of formation is made of and thick 150nm FeCo (Co:30at%) the type main carrier for magnetic copying with silicon chip garden dish.Figure is the uniformly-spaced radial circuit from garden disk center to the radius 20mm-40mm wide 8um in position, and line segregation is the 8um interval in the interior all positions of radius 20mm.
Magnetosphere is to adopt sputter equipment (the 730H type that Ah being Shandong Bagong department produces) sputter to make, and making temperature is 25 ℃, and ar sputtering press power is 3.3 * 10
-4Pa (0.25mTorr), input electric power is 2.54W/cm
2
The subordinate medium use the commercial application type magnetic recording medium (Fuji's film) of the Zip250 that is exclusively used in iomega corp's production, and the coercive force Hc of subordinate medium is 199kA/m (2500Oe).
The subordinate medium make main carrier for magnetic copying and subordinate medium connect airtight reverse 199kA/m (2500Oe) magnetic field of additional and first dc magnetization recorded information are replicated on the subordinate medium behind the following initial stage of condition of 398kA/m (5000Oe) dc magnetization.According to following commentary method the subordinate medium of gained are estimated, and estimated the magnetic complex information.
Embodiment 2
Except the making temperature inversion of embodiment 1 described main carrier for magnetic copying is 60 ℃, other and the main carrier for magnetic copying of embodiment 1 identical making embodiment 2, and estimated the magnetic identical with embodiment 1 and duplicated.
Embodiment 3
Except the magnetosphere of embodiment 1 described main carrier for magnetic copying being transformed to CoFeNi (atomic ratio is 65: 22: 13), other and the main carrier for magnetic copying of embodiment 1 identical making embodiment 3, and evaluation and embodiment 1 identical magnetic duplicates.
Implement embodiment 4
Except the magnetosphere of embodiment 1 main carrier for magnetic copying being transformed to FeNi (atomic ratio is 80: 20), other and the main carrier for magnetic copying of embodiment 1 identical making embodiment 4, and estimated the magnetic identical with embodiment 1 and duplicated.
Comparing embodiment 1
Except the magnetosphere of embodiment 4 main carrier for magnetic copying being made temperature inversion is 100 ℃, other and the main carrier for magnetic copying of embodiment 4 identical making to comparison embodiment 1, and estimated the magnetic identical with embodiment 1 and duplicated.
Comparing embodiment 2
(atomic ratio is 76: 14: 6: 4), other are identical with comparing embodiment 1, obtain the main carrier of comparing embodiment 2 except the magnetosphere of comparing embodiment 1 described main carrier for magnetic copying being transformed to NiFeCuMo.
Comparing embodiment 3
Except the magnetosphere sputtering pressure the main carrier for magnetic copying of embodiment 1 is transformed to 1.3 * 10
-2Pa (10mTorr) in addition, other and the main carrier for magnetic copying of embodiment 1 identical making comparing embodiment 3, and estimated the magnetic identical and duplicated with embodiment 1.
Comparing embodiment 4
Except the magnetosphere of the main carrier for magnetic copying of embodiment 1 is provided with the IrMn basic unit, other is identical with embodiment 1, has made the main carrier for magnetic copying of comparing embodiment 4.It is 200 ℃ that IrMn basic unit makes temperature, and sputtering pressure is 3.3 * 10
-2Pa (25mTorr), film thickness are 30nm.
Evaluation method
The assay method in 1 anisotropy magnetic field
With the AC erasing machine magnetic is duplicated main carrier and carry out AC erasing, subsequently, begin to make magnetic field to increase from the magnetic field initial point, measure magnetization value with soft magnetic data oscillating mode magnetometer (VSM).When magnetization value reached maximum, the magnetic field when promptly saturated was as anisotropy magnetic field.
The rank of 2 reproducing signals
With electromagnetism transform characteristic detecting apparatus (coelectron system: SS-60) reproducing signals of subordinate medium is estimated.For magnetic head, adopt head gap: the inductive magnetic head of 0.23um track width: 3.0um is observed regenerated signal, magnetic is duplicated in the subordinate media disc of back perimembranous (disk radius 20mm) measure.Measure 1 week of disk and divide magnetic signal intensity (TAA output), show as DTAA.
The ratio of the magnetic signal intensity (HTAA) of said head record regenerating with DTAA defined with (1) formula:
Signal intensity ratio=(DTAA/HTAA) * 100 (1)
(1) the formula value is evaluated as well greater than 95%, is evaluated as bad less than this value.In order to confirm that magnetic duplicates back signal rank, the regenerated signal of observing regenerated signal obtain is imported into digital oscilloscope (LC334AM of レ Network ロ イ corporate system) regenerated signal is estimated with signal full width at half maximum (PW50).PW50 is evaluated as well less than 300nm, is evaluated as bad greater than this value.
Table 1
| Anisotropy magnetic (Hk) (kA/m) | Hk/Hc | Signal intensity ratio * 100 | Full width at half maximum (nm) |
Embodiment 1 embodiment 2 embodiment 3 embodiment 4 comparing embodiments 1 comparing embodiment 2 comparing embodiments 3 comparing embodiments 4 | 15.9 2.4 6.4 0.4 0.07 0.04 40.0 44.6 | 8.0×10
-2 1.2×10
-2 3.2×10
-2 2.0×10
-3 3.6×10
-4 2.0×10
-4 2.0×10
-1 2.2×10
-1 | 96 (well) 96 (well), 97 (well) 97 (well), 96 (well) 93 (bad), 90 (bad) 91 (bad) | 282 (well) 280 (well), 279 (well) 277 (well), 301 (bad) 305 (bad), 280 (well) 283 (well) |
Use in the magnetic duplicating method of main carrier for magnetic copying in the invention described above, can retract at hard disk, at capacity on the disks such as magnetic disk medium, the soft medium of high capacity and can carry out that stable magnetic duplicates and the rank that can not reduce reproducing signals following the tracks of with preformats such as servosignal or address information signal, regeneration timing signal record, and, throughput rate at short notice.