JP6431496B2 - Alloy for seed layer of magnetic recording medium, sputtering target material, and magnetic recording medium - Google Patents

Description

  The present invention relates to a Ni-based alloy sputtering target material characterized by miniaturization of a seed layer thin film.

  In recent years, the progress of perpendicular magnetic recording has been remarkable, and in order to increase the capacity of the drive, the recording density of the magnetic recording medium has been increased. A realizable perpendicular magnetic recording system has been put into practical use. Here, the perpendicular magnetic recording method is a method suitable for high recording density, in which the easy axis of magnetization is oriented perpendicularly to the medium surface in the magnetic film of the perpendicular magnetic recording medium. .

  In the perpendicular magnetic recording system, a recording medium having a magnetic recording film phase and a soft magnetic film phase with an increased recording density has been developed. In such a medium structure, a seed is interposed between the soft magnetic layer and the magnetic recording layer. A recording medium on which a layer or an underlayer is formed has been developed. In recent years, there has been a demand for further miniaturization of the magnetic recording layer in order to improve the recording density of the storage medium. In general, a NiW-based alloy is used for the seed layer for the perpendicular magnetic recording system as disclosed in, for example, Japanese Patent Application Laid-Open No. 2009-155722 (Patent Document 1). Moreover, as disclosed in JP 2012-128933 A (Patent Document 2), in a Ni-Fe-Co-M alloy, a target material for a sheet layer containing W, Mo, Ta, Cr, V, and Nb as an M element. Thus, an invention has been proposed in which W, which is one of bcc metals having a high melting point, is included, thereby improving the orientation to the (111) plane required for the seed layer and making the crystal grains finer. ing.

JP 2009-155722 A JP 2012-128933 A

However, Ni as a seed layer for the perpendicular magnetic recording method as in Patent Document 1 described above.
By using W which is one of bcc-based metals having a high melting point as described in Patent Document 2 and using W-based alloys, or to the (111) plane required for the seed layer Although the orientation is improved and the crystal grains are made finer, there is a limit to the use of a refractory metal made of a Ni-based seed layer alloy target material as in Patent Document 2.

  In order to solve the above-described problems, the inventors have intensively developed, and as a result, provide an alloy for a seed layer of a Ni-based magnetic recording medium for a sheet layer and a sputtering target material having a crystal grain size smaller than that of Patent Document 2. Is. That is, by including a noble metal (Au, Ag, Pd, Rh, Ir, Ru, Re, Pt) instead of a bcc metal having a high melting point, the orientation of the (111) plane of the seed layer is improved. Furthermore, the inventors have found that the crystal grain size becomes finer and have completed the invention.

The gist of the invention is that
(1) The Ni-based sputtering target material is made of a Ni-Fe-Co-M alloy, and the alloy is at. %, And one or more elements selected from Au, Ag, Pd, Rh, Ir, Ru, Re, and Pt as M1 elements in total 2 to 20 at. %, The balance is made of Ni, Fe, Co and unavoidable impurities, and the content ratio of Ni, Fe, Co is at. An alloy for a seed layer of a magnetic recording medium, wherein Ni: Fe: Co = 100 to 20: 0 to 50: 0 to 60 in terms of% ratio.

  (2) In addition to the Ni—Fe—Co—M alloy described in (1) above, Al, Ga, In, Si, Ge, Sn, Zr, Ti, Hf, B, Cu, P, C as M2 elements , Mn, one or more elements selected from Mn in total exceeding 0 to 10 at. % Ni-based sputtering target material characterized by containing.

(3) A sputtering target material comprising the seed layer alloy for a magnetic recording medium according to any one of (1) and (2).
(4) A magnetic recording medium using the seed layer alloy according to any one of (1) and (2).

According to the present invention, N that enables the crystal grain size of the seed layer in the perpendicular magnetic recording medium to be reduced.
An i-Fe-Co-M alloy target material can be provided, which is an extremely effective technique for improving the recording density of a magnetic storage medium.

The reason for limiting the invention according to the present invention will be described below.
As described above, the most important feature of the present invention is that the seed layer is formed by including a noble metal (Au, Ag, Pd, Rh, Ir, Ru, Re, Pt) instead of the bcc metal having a high melting point. The (111) plane orientation is improved, and the crystal grain size is further refined.
One or two or more elements selected from Au, Ag, Pd, Rh, Ir, Ru, Re, and Pt as M1 elements in total 2 to 20 at. The reason why the content is% is shown below.

  In the Ni—Fe—Co—M alloy, when Au, Ag, Pd, Rh, Ir, Ru, Re, and Pt are hereinafter referred to as M1 elements, these M1 elements have an fcc structure within the component range defined in the present invention. Although the mechanism is not clear by adding to a certain Ni—Fe—Co system, it is an element that improves the orientation to the (111) plane required for the seed layer and refines the crystal grains. One type or two or more types of Au, Ag, Pd, Rh, Ir, Ru, Re, and Pt are set to 2 to 20% in the amount of at%. However, if it is less than 2%, the effect is not sufficient, and the alloy for the seed layer is required to be an fcc single phase. However, if it exceeds 20%, the fcc structure cannot be maintained or becomes amorphous. Therefore, the range is made 2 to 20%. Preferably it is 5 to 15%.

The content ratio of Ni, Fe, and Co is at. The reason why Ni: Fe: Co = 100 to 20: 0 to 50: 0 to 60 in terms of% ratio is shown below.
In the Ni—Fe—Co—M alloy according to the present invention, when Ni: Fe: Co = α: β: γ, which is the ratio of Ni, Fe, and Co, α: 100 to 20 is set. The reason why it is 20 or more is that if it is less than 20, the coercive force is increased as described above. Therefore, the range was set to 100-20. Preferably it is set to 100-60.

at ratio β: 0 to 50
Fe is an element that reduces the coercive force and also improves the orientation of the film. However, since coercive force will become high when it exceeds 50, the range was made into 0-50. Preferably it is 2 to 50%, more preferably 10 to 40.

at ratio γ: 0 to 60
Co is an element that reduces the coercivity in the (111) direction. However, since the coercive force increases when it exceeds 60, the upper limit is set to 60. Preferably it is 40 or less.
In the Ni—Fe—Co—M alloy, if Au, Ag, Pd, Rh, Ir, Ru, Re, and Pt are hereinafter referred to as M1 elements, the M1 element is fcc within the component range defined in the present invention. Although the mechanism is not clear by adding to the Ni—Fe—Co system, it is an element that improves the orientation to the (111) plane required for the seed layer and refines the crystal grains.

Furthermore, Al, Ga, In, Si, Ge, Sn, Zr, Ti, Hf, B, Cu, P, C
, Mn is hereinafter referred to as an M2 element, the M2 element is an element that orients the (111) plane and is an element that refines crystal grains. One or two or more of Al, Ga, In, Si, Ge, Sn, Zr, Ti, Hf, B, Cu, P, C, and Mn are set to at least 0 and more than 10%. However, if it exceeds 10%, a compound is formed or becomes amorphous, so the upper limit is made 10%. Preferably it is 5%. M1 + M2 is preferably 25 at% or less, more preferably 20 at% or less.

Hereinafter, the present invention will be described more specifically with reference to examples.
Usually, the seed layer in a perpendicular magnetic recording medium can be formed on a glass substrate or the like by sputtering a sputtering target material having the same component as that of the seed layer. Here, the thin film formed by sputtering is rapidly cooled. As a test material in the present invention, a quenched ribbon manufactured by a single roll type quenching apparatus is used. This is a simple evaluation of the influence of the components on various properties of a thin film formed by quenching by sputtering in a simple manner using a liquid quenching ribbon.

  The conditions for preparing the quenched ribbon are as follows: 30 g of raw material weighed so as to have the composition shown in the table is depressurized with a water-cooled copper mold having a diameter of about 10 and a length of about 40 mm, and arc-melted in Ar. This was a melting base material. The conditions for preparing the quenching ribbon are as follows. This molten base material is set in a quartz can having a diameter of 15 mm by a single roll method, the tap nozzle diameter is 1 mm, the atmospheric pressure is 61 kPa, the spray differential pressure is 69 kPa, the copper roll (diameter is 300 mm) The hot water was discharged at a rotation speed of 3000 rpm and a gap of 0.3 mm between the copper roll and the hot water nozzle. The hot water temperature was set immediately after each molten base material was melted. The following items were evaluated using the thus prepared quenched ribbon as a test material.

As an evaluation of the crystal grain size of the quenched ribbon, in the roll direction of the cross-sectional microstructure image of the quenched ribbon,
Measured according to JIS G0551 “Microscopic test method for steel and crystal grain size”. P / Lt of 1.4 or more was I, 1.2 or more, less than 1.4 was II, and less than 1.2 was III.
For the evaluation of the coercive force of the rapidly cooled ribbon, a vibration sample type coercive force meter was used, and a quenching ribbon was attached to the sample stage with double-sided tape, and the initial applied magnetic field was 144 kA / m. A coercive force of 300 A / m or less was designated as I, 300 A / m or more and 500 A / m or less as II, and 500 A / m or less as III.

As the evaluation of the saturation magnetic flux density of the quenched ribbon, it was measured with an applied magnetic field of 1200 kA / m with a VSM apparatus (vibrating sample magnetometer). The weight of the test material was about 15 mg, and 0.2 T or more was evaluated as I, and less than 0.2 T was evaluated as III.
For evaluating the (111) plane orientation of the quenched ribbon, the seed layer formed by sputtering has an fcc structure. The seed layer is rapidly cooled to orient (200). Usually, if random orientation is performed, the X-ray diffraction intensity of the (111) plane and the (200) plane will be higher for I (200) than for I (111). Therefore, the orientation of the (111) plane was evaluated by the following method.

The test material was attached to a glass plate with a double-sided tape, and a diffraction pattern was obtained with an X-ray diffractometer. At this time, the test material was affixed so that a measurement surface might become a copper roll contact surface of a rapidly cooled ribbon. The X-ray source was Cu-α ray and measured at a scan speed of 4 ° / min. I (111) / I (200), which is the intensity ratio between the intensity I (111) of the X-ray diffracted by the (111) plane of this diffraction pattern and the intensity I (200) of the (200) plane, is 0.7. Those less than III were taken as III, and those above 0.7 were taken as I. In addition, those in which a compound was produced and those that were made amorphous were designated III.

  As shown in Tables 1-7, no. 1-107 and 167-230 are examples of the present invention. Reference numerals 108 to 166 and 231 to 236 are comparative examples.

In addition, it describes in the component composition shown to Tables 1-7, for example, No .. Since 1 is Ru at 2 at%, (Ni2Fe) is 100% -2% and 98 at%, and when 98% is 1, Ni is (100-2) and Fe is a ratio of 2. . Further, since Co is not included, the ratio corresponds to zero. Similarly, no. If it is 62, the total amount of Pt and In is 7 at%, so (Ni50Fe) is 93% at 100% -7%. When 93 at% is 1, Ni is 100-50 and Fe is a ratio of 50. In other words, since Ni and Fe have the same ratio in terms of at ratio, this means that they are 46.5 at%, which is half of 93 at%.

Comparative Example No. 108 to 123 and 128 to 134 are inferior in crystal grain size when W is added instead of the M element. Comparative Example No. No. 135 has inferior crystal grain size when Cr and V are added instead of M. Comparative Example No. 136, when Nb and V are added instead of M, the crystal grain size is inferior. Comparative Example No. In 137, when Nb and Mo are added instead of M, the crystal grain size is inferior. Comparative Example No. Since 138 is Ni alone, it has a high coercive force and is inferior in orientation and crystal grain size. Comparative Example No. 139 is inferior in orientation and crystal grain size because there is no M element. Comparative Example No. Since 140 has a high Fe content, the coercive force is high. Comparative Example No. No. 141 has a low Ag content of 7 and a high Al content, so that the coercive force is slightly high and the orientation is inferior. Comparative Example No. Since 142 has a high Pt content, it is difficult to measure the coercive force, and the saturation magnetic flux density and orientation are inferior.

Comparative Example No. Since 143 and 144 have a low Ag content and a high Zr and B content, the orientation is inferior. Comparative Example No. 145 has a low Ni content and a high Co content, so the coercive force is high. Comparative Example No. 146 has a low Ni content and a high Fe content, so the coercive force is high. Comparative Example No. Since 147 has a low Re content, it has a high coercive force and inferior orientation and crystal grain size. Comparative Example No. 148 is inferior in all properties because of the high Re content. Comparative Example No. No. 149 has a high coercive force due to a low Pt content, and is inferior in orientation and crystal grain size.

Comparative Example No. No. 150 is inferior in all properties because of high Pt content. Comparative Example No.
No. 151 has a low coercive force due to a low content of Rh, and is inferior in orientation and crystal grain size. Comparative Example No. Since 152 has a high content of Rh, all characteristics are inferior. Comparative Example No. Since 153 has a low Ir content, it has a high coercive force and is inferior in orientation and crystal grain size. Comparative Example No. 154 is inferior in all properties because of its high Ir content. Comparative Example No. Since 155 has a low Au content, the coercive force is high, and the orientation and crystal grain size are inferior. Comparative Example No. No. 156 is inferior in all properties due to the high Au content.

  Comparative Example No. Since 157 has a high Ga content, the orientation and crystal grain size are inferior. Comparative Example No. 158 is inferior in orientation and crystal grain size because of its high In content. Since comparative example No159 has high content of Si, orientation and a crystal grain size are inferior. Comparative Example No. No. 160 is inferior in orientation and crystal grain size because of the high Ge content. Comparative Example No. Since 161 has a high Sn content, the orientation and crystal grain size are inferior. Comparative Example No. Since 162 has a high Zr content, the orientation and the crystal grain size are inferior. Comparative Example No. Since 163 has a high Ti content, the orientation and crystal grain size are inferior. Comparative Example No. Since 164 has a high Hf content, the orientation and crystal grain size are inferior. Comparative Example No. Since 165 has a high B content, the orientation and the crystal grain size are inferior. Comparative Example No. 166 is inferior in orientation and crystal grain size because of high Cu content.

  Comparative Example No. Since 231 has a low content of Fe + Co, the coercive force is inferior. Comparative Example No. Since 232 has a low content of Fe + Co, the coercive force is inferior. No. Since 233 has a low content of Fe + Co, coercive force is inferior. No. Since 234 has a low content of Fe + Co, the coercive force is inferior. No. Since 235 has a low content of Fe + Co, the coercive force is inferior. No. Although 236 is within the conditions of the present invention, since the Pt addition amount does not exceed 4.9 and 5, the characteristics are slightly inferior. Therefore, it was set as a comparative example.

As described above, in the Ni-Fe-Co-M alloy, by restricting to a certain content, by restricting to this region, it has magnetism and increases the magnetic permeability in the (111) direction. Thus, by providing magnetism to the Ni-based seed layer, there is an excellent effect that the distance between the magnetic head and the soft magnetic underlayer can be shortened.

Next, the example of the manufacturing method of sputtering target material is shown. Invention Example No. 1 in Table 1 2,
No. 10, no. 14, no. 18, no. 25, no. 35, no. 38, no. 55, no. 63, no. 82, no. 91, no. 97, no. 101, no. 107, Comparative Example No. 114, Comparative Example No. 135, Comparative Example No. 136, Comparative Example No. 140, Comparative Example No. 146, Comparative Example No. 153, Comparative Example No. 162, Invention Example No. 177, no. 188, No194, No. 206, no. 208, no. 211, no. 217, no. 223, no. 229, Comparative Example No. 231, Comparative Example No. The melted raw material weighed in the 234 composition was induction-heated and melted in a refractory crucible in a reduced pressure Ar gas atmosphere, then poured out from a nozzle having a diameter of 8 mm at the bottom of the crucible and atomized with Ar gas. This gas atomized powder was used as a raw material powder, filled into a carbon steel capsule having a diameter of 250 mm and a length of 100 mm, and vacuum deaerated and sealed.

  The powder-filled billet was HIP molded under the conditions of a molding temperature of 1100 ° C., a molding pressure of 147 MPa, and a molding time of 5 hours. This HIP body was processed into a disk shape having a diameter of 180 mm and a thickness of 7 mm by wire cutting, lathe processing, and planar polishing to obtain a sputtering target material.

A sputtering target material was used for these 32 kinds of component compositions, and a sputtered film was formed on a glass substrate. The microstructure of the film is the same as that of Example No. of the present invention. 2, No. 10, no. 14, no. 18, no. 25, no. 35, no. 38, no. 55, no. 63, no. 82, no. 91, no. 97, no. 101, no. 107, no. 177, no. 188, No194, No. 206, no. 208, no. 211, no. 217, no. 223, no. No. 229 shows a fine crystal grain size in any of the comparative examples. 114, Comparative Example No. 135, Comparative Example No. 136, Comparative Example No. 153, Comparative Example No. 162 did not have a fine crystal grain size.

The X-ray diffraction pattern is shown in Example No. of the present invention. 2, No. 10, no. 14, no. 18, No
. 25, no. 35, no. 38, no. 55, no. 63, no. 82, no. 91, no. 97, no. 101, no. 107, no. 177, no. 188, No194, No. 206, no. 208, no. 211, no. 217, no. 223, no. 229 shows good orientation in any case, and Comparative Example No. 153, Comparative Example No. 162 did not show good orientation.

Further, when the magnetic properties were measured in the same manner as the quenched ribbon, the present invention example No. 2, No.
10, no. 14, no. 18, no. 25, no. 35, no. 38, no. 55, no. 63, no. 82, no. 91, no. 97, no. 101, no. 107, no. 177, no. 188, No194, No. 206, no. 208, no. 211, no. 217, no. 223, no. No. 229 shows good magnetic properties, and Comparative Examples No. 140 and No. 146, Comparative Example No. 153, Comparative Example No. 231, Comparative Example No. 234 did not show good magnetic properties.

Also, the X-ray diffraction pattern was measured in the same manner as the quenched ribbon, and the results were I, II, and III similar to the results evaluated with the quenched ribbon. In summary, it was confirmed that the results of the evaluation with the quenched ribbon and the evaluation of the sputtered film formed using the sputtering target material have the same tendency.


Patent Applicant Sanyo Special Steel Co., Ltd.
Attorney: Attorney Shiina

Claims (4)

An alloy used for a Ni-based sputtering target material, which is made of a Ni—Fe—Co—M alloy. %, And one or more elements selected from Au, Ag, Pd, Rh, Ir, Ru, Re, and Pt as M1 elements in total 2 to 20 at. %, The balance is made of Ni, Fe, Co and unavoidable impurities, and the content ratio of Ni, Fe, Co is at. An alloy for a seed layer located between a soft magnetic layer and a magnetic recording layer in a magnetic recording medium, wherein Ni: Fe: Co = 100 to 20: 0 to 50: 0 to 60 in terms of% ratio. The Ni—Fe—Co—M alloy according to claim 1 further includes Al, Ga, In, Si, Ge, Sn, Zr, Ti, Hf, B, Cu, P, C, Mn, and Sn as M2 elements. 1 or more elements selected from the group consisting of more than 0 and 10 at. An alloy for a seed layer located between a soft magnetic layer and a magnetic recording layer in a magnetic recording medium. A sputtering target material comprising the seed layer alloy of the magnetic recording medium according to claim 1. A magnetic recording medium using the seed layer alloy according to claim 1.