Sputtering target, method for manufacturing a multilayer film, multilayer film, and magnetic recording medium

Abstract

The present invention provides a sputtering target which enables a magnetic layer of a magnetic recording medium to maintain high coercivity, while being capable of improving magnetic separation between magnetic particles. This sputtering target contains Co and Pt as metal components, while containing NbO2 as a metal oxide component. Alternatively, this sputtering target contains Co and Pt as metal components, while having a phase that contains all of Co, Nb and O.

Description

Technical Field

[0001] The present invention relates to a sputtering target. Further, the present invention relates to a method for manufacturing a laminated film using the sputtering target of the present invention. Furthermore, the present invention relates to a laminated film and a magnetic recording medium.

Background Art

[0002] In a hard disk drive, a perpendicular magnetic recording method for recording magnetic fields in a direction perpendicular to the recording surface has been put into practical use. This method is widely adopted because it enables higher-density recording compared to the conventional in-plane magnetic recording method.

[0003] A magnetic recording medium using the perpendicular magnetic recording method generally comprises a laminated structure in which an adhesion layer, a soft magnetic layer, an underlayer such as a Seed layer and a Ru layer, an intermediate layer, a magnetic layer, and a protective layer are sequentially laminated on a substrate such as aluminum or glass. Among these, in the magnetic layer, there is a granular film in which SiO2 or other metal oxides are dispersed in a Co-Pt-based alloy mainly composed of Co at the lower part, and it has a high saturation magnetization Ms and magnetic anisotropy Ku. Further, the intermediate layer laminated on the lower side of the magnetic layer has a structure in which the same metal oxides are dispersed in a Co-Cr-Ru-based alloy or the like, and may contain a relatively large amount of Ru, Cr, etc. to make it non-magnetic.

[0004] In such a magnetic layer and intermediate layer, the above-mentioned metal oxides that become non-magnetic materials precipitate at the grain boundaries of magnetic particles such as Co alloys oriented in the vertical direction, reducing the magnetic interaction between magnetic particles, thereby improving the noise characteristics and realizing a high recording density.

[0005] In general, each layer such as the magnetic layer and the intermediate layer is formed by sputtering onto a substrate using a sputtering target having a predetermined composition or structure. Conventionally, there is, for example, the one described in Patent Document 1 (Japanese Patent No. 5960287).

Prior Art Documents

Patent Documents

[0006] [Patent Document 1] Patent No. 5960287 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] Incidentally, in order to achieve high density in hard disk drives, it is necessary to increase the magnetic anisotropy Ku to ensure the thermal stability of the recording layer formed on the magnetic recording medium, and to achieve high magnetic separation of magnetic particles within the recording layer to achieve high resolution.

[0008] However, in magnetic layers with high saturation magnetization Ms, which achieves the high magnetic anisotropy Ku described above, the exchange coupling between magnetic particles is strong, resulting in poor magnetic separation between magnetic particles. On the other hand, if a large amount of metal oxide is added to improve magnetic separation, the metal oxide penetrates into the magnetic particles, degrading the crystallinity of the magnetic particles. Consequently, saturation magnetization Ms and magnetic anisotropy Ku decrease, and coercivity Hc decreases. Another method to increase magnetic anisotropy Ku is to raise the substrate temperature during film formation, but this also reduces magnetic separation between magnetic particles and decreases coercivity Hc. To achieve high density, it is important to achieve both high coercivity Hc in the recording layer and good magnetic separation between magnetic particles within the recording layer.

[0009] The present invention was completed in view of the above-mentioned problems, and in one embodiment, aims to provide a sputtering target that can maintain a high coercivity Hc in the magnetic layer of a magnetic recording medium and improve the magnetic separation between magnetic particles. In another embodiment, the present invention aims to provide a method for manufacturing a laminated film using such a sputtering target, a laminated film, and a magnetic recording medium. [Means for solving the problem]

[0010] As a result of diligent research, the inventors have found that by including Nb as an oxide in a specific form as a non-magnetic metal oxide dispersed in the Co alloy, which is the magnetic material of the magnetic layer, the magnetic separation between magnetic particles can be significantly improved. Furthermore, they have found that this allows the high coercivity Hc of the Co-Pt-based magnetic layer to be maintained. The present invention was completed based on the above findings and is illustrated below.

[0011] [1] A sputtering target containing Co and Pt as metal components and NbO2 as a metal oxide component. [2] A sputtering target as described in [1], wherein the NbO2 content is 0.5 mol% to 30 mol%. [3] A sputtering target containing Co and Pt as metallic components, and having a phase that contains all of Co, Nb, and O. [4] The sputtering target described in [3], wherein a diffraction peak is observed at 2θ = 30.27° ± 1° when measured using an X-ray diffractometer. [5] When measured under the following conditions, a diffraction peak is observed at 2θ = 30.27° ± 1° for the sputtering target described in [4]: (1) The analysis area of ​​the sputtering target is the cross-section perpendicular to the sputtering surface. (2) Cu-Kα is used as the X-ray source. (3) The tube voltage is 40kV. (4) The tube current is 30 mA. (5) The divergence slit is 1°. (6) The divergence vertical limiting slit is 10 mm. (7) The scattering slit is 8 mm. (8) The light-receiving slit is open. (9) A goniometer with a horizontal sample type shall be used. (10) The scan speed is 10° / min. (11) The scan step is 0.01°. (12) The measurement range is 2θ = 20° to 80°. (13) A fitting method is used for background removal. (14) The analysis location is polished with #2000 waterproof abrasive paper and further buffed using a slurry in which alumina abrasive grains with a particle size of 0.3 μm are dispersed. (15) Among the analysis locations, a flat and less uneven surface is measured. [6] As the metal oxide component, further, TiO2, SiO2, Cr2O3, B2O , , Contains at least one metal oxide of CoO and Co3O4, and the total content of the metal oxide in the sputtering target is 20 vol% to 60 vol%. The sputtering target according to any one of [1] to [5]. [7] s<000008??2>The sputtering target according to any one of [1] to [6], wherein the content of Pt is 2 mol% to 25 mol%. [8] A method for manufacturing a laminated film, including forming a magnetic layer by sputtering using the sputtering target according to any one of [1] to [7] on a Ru-containing underlayer [[ID=2??2]]][9] A laminated film having a Ru-containing underlayer and a magnetic layer formed on the underlayer and containing Co and Pt as metal components, wherein the magnetic layer contains NbO2 as a metal oxide component.

[10] The magnetic layer further contains at least one metal oxide of CoO and Co3O4 as a metal oxide component. The laminated film according to [9]. 3、

[11] A magnetic recording medium including the laminated film according to [9] or

[10] .

Advantages of the Invention

[0012] According to an embodiment of the present invention, it is possible to provide a sputtering target that can maintain a high coercive force in the magnetic layer of a magnetic recording medium and improve the magnetic separability between magnetic particles. Further, according to another embodiment of the present invention, it is possible to provide a method for manufacturing a laminated film using such a sputtering target, a laminated film, and a magnetic recording medium.

Brief Description of the Drawings

[0013] [Figure 1] FIG. 1 is a schematic diagram showing the layer structure of a laminated film manufactured in an example of the present invention. [[ID=⑨]] [Figure 2] FIG. 2 is a diagram showing the measurement results using XRD of a target in an example of the present invention.

Modes for Carrying Out the Invention

[0014] Next, embodiments of the present invention will be described. It should be understood that the present invention is not limited to the following embodiments, and design changes, improvements, etc. can be appropriately made based on the ordinary knowledge of those skilled in the art without departing from the gist of the present invention.

[0015] The sputtering target of the present embodiment is characterized by containing Co and Pt as metal components and containing NbO2 as a metal oxide component. More specifically, the sputtering target of the present embodiment has a structure in which a metal oxide containing an Nb oxide is dispersed in an alloy of Co and Pt. In this specification, when referring to the metal oxide component, unless otherwise specified, it is an explanation of the metal oxide as a raw material of the sputtering target.

[0016] This sputtering target is particularly preferred for forming a magnetic layer located on the intermediate layer of a magnetic recording medium using a perpendicular magnetic recording method. In this case, in the magnetic layer formed by sputtering using the sputtering target, the above-mentioned metal components constitute magnetic particles, while the metal oxide containing NbO2 acts as a non-magnetic material, uniformly distributed around the vertically oriented magnetic particles, effectively reducing magnetic interactions between magnetic particles.

[0017] (1.Composition) The metallic component of the sputtering target consists mainly of Co, with the addition of Pt. In particular, the metallic component is a Co alloy containing Pt.

[0018] The Pt content is preferably between 2 mol% and 25 mol%. If the total Pt content is too high, the magnetic anisotropy may decrease or the crystallinity of the magnetic particles may decline. On the other hand, if the ratio of the total Pt content to Co is too low, there is a concern that the magnetic anisotropy will be insufficient. The Pt content in the sputtering target can be determined, for example, by analyzing it using ICP and basing the analysis on the results.

[0019] The sputtering target of this embodiment may further contain non-magnetic metal components such as Cr, Ru, Ti, Cu, Ta, W, V, Rh, etc. The additional inclusion of such metals offers the advantage of adjusting the saturation magnetization and magnetic anisotropy while maintaining the crystallinity of the magnetic particles. While most of these metals are typically included as metallic components, some may be present as metal oxides due to oxidation during sintering during manufacturing, as described later.

[0020] Furthermore, the sputtering target of this embodiment contains at least NbO2 as a metal oxide component. By including NbO2, it is possible to improve the magnetic separation between magnetic particles while maintaining coercivity.

[0021] While there is no intention to restrict the present invention by theory, Nb oxides have the advantage of having appropriate wettability with Co and remaining stable even if some oxygen is missing, thus allowing grain boundaries to be formed around magnetic particles with a uniform width without the oxide penetrating into the magnetic particles. The inventors have also observed that this advantage becomes more pronounced when Nb oxides with a low oxidation state are used. This is thought to be because the wettability with Co improves when a composite oxide with Co is formed. Therefore, by including NbO2, which has a low oxidation state among Nb oxides, we were able to achieve magnetic separation between magnetic particles that could not be achieved with conventional techniques.

[0022] In the sputtering target of this embodiment, the NbO2 content is preferably 0.5 mol% to 30 mol% of the total composition of the raw materials of the sputtering target. By having an NbO2 content of 0.5 mol% or more, the effect of improving the magnetic separation between magnetic particles can be reliably achieved. On the other hand, from the viewpoint of ensuring a plateau in the effect, saturation magnetization of the magnetic film, and magnetic anisotropy to obtain high coercivity, the NbO2 content is preferably 30 mol% or less. From this viewpoint, an NbO2 content of 20 mol% or less is more preferable, and an even more preferable of 10 mol% or less.

[0023] Furthermore, the sputtering target of this embodiment may contain, in addition to NbO2, at least one of TiO2, SiO2, Cr2O3, and B2O3 as a metal oxide component. This makes it possible to obtain the effects of the metal oxides TiO2, SiO2, Cr2O3, or B2O3 in addition to the effects of NbO2. It may also contain CoO and Co3O4 as metal oxide components. Adding these Co oxides can enhance the effects of NbO2.

[0024] When metal oxides other than NbO2 are included, the total content of metal oxides present in the sputtering target, i.e., the total content of metal oxides constituting the microstructure of the sputtering target, is preferably 20 vol% to 60 vol%. If the total content of metal oxides is 20 vol% or more, sufficient magnetic separation between magnetic particles can be ensured. On the other hand, if the total content of metal oxides is 60 vol% or less, a decrease in coercivity can be prevented. For this reason, a total content of metal oxides of 30 vol% to 55 vol% is even more preferable. For example, by acquiring an image of the surface of the sputtering target using SEM and performing EDS analysis, the particles in the image can be classified into metal particles and metal oxide particles, and the volume fraction of metal oxides present in the sputtering target can be estimated based on the area ratio of metal particles to metal oxide particles. Furthermore, the content of metal oxides can be estimated not only by observing the surface of the sputtering target, but also based on the density, weight, etc., of the raw material powder. The calculation method based on the raw material powder will be described later.

[0025] (2. Method for manufacturing a sputtering target) The sputtering targets described above can be manufactured using the powder sintering method, and specific examples are as follows:

[0026] First, prepare Co powder, Pt powder, and, if necessary, other metal powders as described above. The metal powder may be a single element or an alloy, and it is preferable that its particle size is in the range of 1 μm to 10 μm, as this allows for uniform mixing and prevents segregation and coarse crystallization. If the particle size of the metal powder is larger than 10 μm, the oxide particles described later may not be uniformly dispersed, and if it is smaller than 1 μm, the sputtering target may deviate from the desired composition due to the oxidation of the metal powder.

[0027] Furthermore, as oxide powders, at least NbO2 powder and, if necessary, at least one powder selected from the group consisting of TiO2, SiO2, Cr2O3, and B2O3 are prepared. Preferably, the oxide powder has a particle size in the range of 1 μm to 30 μm. This allows for more uniform dispersion of oxide particles in the metal phase when mixed with the above metal powder and subjected to pressure sintering. If the particle size of the oxide powder is greater than 30 μm, coarse oxide particles may be produced after pressure sintering, while if it is smaller than 1 μm, aggregation of oxide powder particles may occur.

[0028] Next, the metal powder and oxide powder are weighed to achieve the desired composition. For example, the NbO2 powder is weighed so that it makes up 0.5 mol% to 30 mol% of the total composition of the sputtering target raw materials. Preferably, the NbO2 powder is weighed to make up 0.5 mol% to 20 mol%, and more preferably to make up 0.5 mol% to 10 mol%. When weighing, for example, the Pt powder is weighed so that it makes up 2 mol% to 25 mol% of the total composition of the raw materials. Furthermore, when weighing, the oxide powder used as raw material is weighed so that the total content of metal oxides in the sputtering target is 20 vol% to 60 vol%. The weighed metal powder and oxide powder are then mixed and ground using a known method such as a ball mill. At this time, it is desirable to fill the inside of the container used for mixing and grinding with an inert gas to suppress oxidation of the raw material powder as much as possible. This makes it possible to obtain a mixed powder in which the predetermined metal powder and oxide powder are uniformly mixed.

[0029] Subsequently, the mixed powder obtained in this manner is sintered under pressure in a vacuum or inert gas atmosphere to form a predetermined shape such as a disc. Various pressure sintering methods can be used here, such as hot press sintering, hot hydrostatic sintering, and plasma discharge sintering. Among these, hot press sintering is particularly effective from the viewpoint of improving the density of the sintered body.

[0030] The holding temperature during sintering should be in the range of 700°C to 1500°C, and preferably 800°C to 1400°C. The holding time within this temperature range should preferably be 1 hour or more. Furthermore, the applied pressure during sintering should preferably be 10 MPa to 40 MPa, more preferably 25 MPa to 35 MPa. This allows for the production of a sintered body in which oxide particles are more uniformly dispersed in the metal phase while maintaining high density.

[0031] A sputtering target can be manufactured by performing cutting or other machining on the sintered body obtained by the above-mentioned pressure sintering process using a lathe or the like to create a desired shape.

[0032] (3. The structural structure of the sputtering target) The sputtering target of this embodiment contains NbO2 as a metal oxide component of the raw material, and in accordance with this characteristic, one of its features is that the sputtering target has a phase that contains all of Co, Nb, and O.

[0033] While there is no intention to restrict the present invention by theory, it is hypothesized that magnetic particles in a thin film made using a target containing a phase that includes all of Co, Nb, and O can form oxide grain boundaries of uniform width around them, thereby improving the magnetic separation between magnetic particles. Such a phase is unique to sputtering targets containing NbO2 as a metal oxide component.

[0034] Phases containing all of Co, Nb, and O can be identified, for example, by X-ray diffraction (XRD). Specifically, in an XRD pattern using Cu-Kα, there is a diffraction peak at approximately 2θ = 30.27° ± 1°. In the explanation of Figure 2 described later, it is stated that this diffraction peak corresponds to the peak of CoNb2O6, but this is for example CoNb2O 6-δIt is possible that (δ>0), meaning that the oxygen content may be slightly low. Including these possibilities, the phase was considered to contain all of Co, Nb, and O. This phase is thought to have been formed by the reaction of Co and NbO2.

[0035] Thus, in this embodiment, one means of verifying that the raw material contains NbO2 as a metal oxide component is to check for the presence or absence of a phase containing all of Co, Nb, and O.

[0036] Furthermore, if a phase containing all of Co, Nb, and O is present, it can be inferred that NbO2 is present as a metal oxide in the raw materials. However, if, for example, the NbO2 in the raw materials does not react much with other metal components and / or oxides during the manufacturing process, theoretically, a phase containing all of Co, Nb, and O may not be detected. Also, if the sputtering target contains NbO2 as a metal oxide component, a diffraction peak corresponding to NbO2 may be detected by XRD. At least in such cases, it can be said that NbO2, which constitutes the microstructure, is present in the sputtering target. However, during the sintering process of the raw material powder, almost all of the NbO2 may react with other metal components and / or oxides to form other compounds, so a diffraction peak corresponding to NbO2 may not be detected from the sputtering target.

[0037] (4. Multilayer film) The laminated film comprises at least a base layer and a magnetic layer formed on the base layer. More specifically, the base layer contains Ru, and is generally composed of Ru, or is a layer with Ru as its main component.

[0038] The magnetic layer contains Co and Pt as metal components and Nb oxide as a metal oxide component. The inclusion of Nb oxide in the magnetic layer improves the magnetic separation between magnetic particles. This magnetic layer can be formed by sputtering onto a substrate using a sputtering target having the aforementioned NbO2 phase and / or a phase containing all of Co, Nb, and O.

[0039] Therefore, the magnetic layer, like the sputtering target described above, has an NbO2 content of 0.5 mol% to 30 mol%, and further contains TiO2, SiO2, Cr2O3, and B2O as metal oxide components. 3、 If at least one metal oxide selected from the group consisting of CoO and Co3O4 is included, it is preferable that the total content of metal oxides, including NbO2, be 20 vol% to 60 vol%, that Pt be included in an amount of 2 mol% to 25 mol%, and that Cr and / or Ru be included in an amount of 0.5 mol% to 20 mol% as metal components.

[0040] Each layer of the multilayer film can be formed by depositing the film using a magnetron sputtering apparatus or the like, with a sputtering target having a composition and structure corresponding to each layer.

[0041] Furthermore, the magnetic layer of the laminated film can be formed by depositing it on the underlying layer using sputtering with the aforementioned sputtering target.

[0042] (5. Magnetic recording media) A magnetic recording medium comprises a laminated film having a base layer and a magnetic layer formed on the base layer, as described above. Magnetic recording media are usually manufactured by sequentially forming a soft magnetic layer, a base layer, a magnetic layer, and a protective layer on a substrate such as aluminum or glass. [Examples]

[0043] Next, a sputtering target of this invention was fabricated, and the effect of the magnetic layer deposited using it was confirmed, which will be described below. However, this description is for illustrative purposes only and is not intended to be limiting.

[0044] Multilayer films were manufactured using various sputtering targets. Using a magnetron sputtering apparatus (Canon Anelva C-3010), Cr-Ti (6 nm), Ni-6W (5 nm), and Ru ("LowP-Ru" means Ru sputtered at low gas pressure (1 Pa), and "HighP-Ru" means Ru sputtered at high gas pressure (10 Pa). Both have a film thickness of 10 nm, for a total film thickness of 20 nm) were deposited on a glass substrate in this order. Then, the sputtering targets shown in Table 1 were sputtered at 300 W in an Ar 3.0 Pa atmosphere to deposit a magnetic film with a film thickness of 11 nm. After that, a protective film (OC) of Ru (3 nm) was deposited to prevent oxidation, forming each layer. Here, the magnetic layer shown as "Mag" in Figure 1 was formed by each sputtering target with a different composition as shown in Table 1. The metal composition of each sputtering target is the same, with the metal component being a CoPt alloy containing 27 at% Pt. Examples 1-3 contain NbO2 as the metal oxide component, while Comparative Examples 1 and 2 do not. The volume fraction of the oxide was calculated by estimating the total volume of the sputtering target and the volume of the oxide from the density and weight of the raw material powder, and then calculating the ratio of these two values. Thus, the volume fraction of the oxide can also be calculated based on the raw material powder.

[0045] For each example and comparative example, the coercivity Hc and the magnetic cluster size Dn, which is a high indicator of magnetic separation of magnetic particles, were measured for the laminated films. The measurement methods are as follows.

[0046] The fabricated multilayer film was subjected to an external magnetic field (H) perpendicular to the film using a NeoArk polar Kerr spectrometer (BH-810MS) to measure the Kerr rotation angle (θ) and create a hysteresis curve. The maximum applied magnetic field was ±20 kOe, and the magnetic field sweep rate was 0.5 kOe / second. The obtained hysteresis curve (major hysteresis curve) was analyzed to determine the coercivity Hc.

[0047] Next, the applied magnetic field was initially set to 20 kOe, then swept down to -Hc, and then swept back up to 20 kOe to obtain the minor hysteresis curve. Then, dθ / dH was calculated by differentiating the major and minor loops. The horizontal axis was then remapped to the effective magnetic field (Heff) converted using the calculation formula. Effective magnetic field (Heff) = H - demagnetizing field Hd The value of this demagnetizing field, Hd, was determined such that when plotting dθ / dH obtained from the major loop and dθ / dH obtained from the minor loop with the effective magnetic field on the horizontal axis, the graphs overlap where dθ / dH increases. Next, the saturation magnetization Ms was measured using a sample vibration magnetometer (VSM) manufactured by Tamagawa Seisakusho. The demagnetizing coefficient Nd was calculated using the following formula. The demagnetizing coefficient Nd = Hd / (4πMs) The magnetic cluster size Dn was calculated using the following formula, based on the obtained Nd and the thickness t of the magnetic film in the sample. Magnetic cluster size Dn = t × (1 - Nd 2 ) 1 / 2 / Nd

[0048] [Table 1]

[0049] As shown in Table 1, Examples 1-3, which contained NbO2, yielded relatively high coercivity Hc and relatively low magnetic cluster size Dn, demonstrating the ability to maintain high coercivity while improving magnetic separation between magnetic particles. In contrast, Comparative Examples 1 and 2, which did not contain NbO2, were inferior in terms of coercivity Hc and magnetic cluster size Dn, although the other components were almost the same.

[0050] Furthermore, Figure 2 shows the XRD measurement results of the target for Example 3. The XRD analysis conditions are as follows.

[0051] When analyzing a sputtering target using an X-ray diffractometer (Rigaku Ultima IV), the measurement method can be carried out in accordance with JIS K0131:1996, and the measurement conditions can be as follows. Analysis area of ​​the sputtering target: Cross-section perpendicular to the sputtering surface. X-ray source:Cu-Kα Tube voltage: 40kV Tube current: 30mA Divergence slit: 1° Divergence vertical limiting slit: 10mm Scattering slit: 8mm Light-receiving slit: Open state Goniometer: Horizontal sample type Scan speed: 10° / min Scan step: 0.01° Measurement range: 2θ = 20° to 80° Background Removal: Fitting Method (Specifically, this method involves performing a simplified peak search to remove the peak portion, and then fitting a polynomial to the remaining data. Background removal is performed based on X-ray analysis software (Rigaku Corporation's integrated powder X-ray analysis software PDXL2).)

[0052] The analysis area is polished with #2000 grit waterproof abrasive paper, and then buffed using a slurry containing dispersed alumina abrasive particles with a particle size of 0.3 μm. The flat and smooth surfaces of the analysis area are then measured. Note that "flat and smooth surfaces" is not a strict standard, but simply means that any areas with irregularities that would interfere with the analysis should be avoided.

[0053] The obtained XRD pattern was analyzed using X-ray analysis software (Rigaku Corporation, integrated powder X-ray analysis software PDXL2). As a result, as can be seen in Figure 2, a diffraction peak was observed around 2θ = 30.27° ± 1°. By comparing the position of this observed diffraction peak with the diffraction peak position data for CoNb2O6 on JCPDS card No. 01-072-0482, it was confirmed that the position of the observed peak corresponds to the position of the main peak (2θ = 30.27°) on JCPDS card No. 01-072-0482. In other words, it was confirmed that the material contains a phase containing all of Co, Nb, and O. Note that no diffraction peak corresponding to NbO2 was observed in Figure 2, which is thought to be because, as mentioned above, almost all of the raw material NbO2 reacted with metal components and / or oxides during the sintering process.

Claims

1. It contains Co and Pt as metal components, and 0.5 mol% to 30 mol% NbO as a metal oxide component. 2 A sputtering target containing [a specific substance].

2. A sputtering target containing Co and Pt as metallic components, and having a phase that contains all of Co, Nb, and O.

3. The sputtering target according to claim 2, wherein a diffraction peak is observed at 2θ = 30.27° ± 1° when measured using an X-ray diffractometer.

4. The sputtering target according to claim 3, which, when measured under the following conditions, exhibits a diffraction peak at 2θ = 30.27° ± 1°: (1) The analysis area of ​​the sputtering target is the cross-section perpendicular to the sputtering surface. (2) Cu-Kα is used as the X-ray source. (3) The tube voltage is 40 kV. (4) The tube current is 30 mA. (5) The divergence slit is 1°. (6) The divergence longitudinal limiting slit is 10 mm. (7) The scattering slit is 8 mm. (8) The light-receiving slit is open. (9) A goniometer with a horizontal sample type shall be used. (10) The scan speed is 10° / min. (11) The scan step is 0.01°. (12) The measurement range is 2θ = 20° to 80°. (13) A fitting method is used for background removal. (14) The analysis area was polished with #2000 waterproof abrasive paper and then buffed with a slurry containing dispersed alumina abrasive particles with a particle size of 0.3 μm. (15) Of the analysis locations, measure the flat surface with minimal irregularities.

5. As the metal oxide component, further, TiO 2 , SiO 2 , Cr 2 O 3 , B 2 O 3、 CoO and Co 3 O 4 The sputtering target according to any one of claims 1 to 4, containing at least one kind of metal oxide among them, and the total content of the metal oxide in the sputtering target being 20 vol% to 60 vol%.

6. A sputtering target according to any one of claims 1 to 4, wherein the Pt content is 2 mol% to 25 mol%.

7. A method for manufacturing a laminated film, comprising forming a magnetic layer on a Ru-containing underlayer by sputtering using a sputtering target described in any one of claims 1 to 4.

8. A laminated film comprising a base layer containing Ru and a magnetic layer formed on the base layer and containing an alloy containing Co and Pt as metal components, wherein the magnetic layer contains 0.5 mol% to 30 mol% NbO as a metal oxide component. 2 A multilayer film containing [a specific component].

9. The magnetic layer further contains TiO as a metal oxide component. 2 SiO 2 , Cr 2 O 3 , B 2 O 3、 CoO and Co 3 O 4 The laminated film according to claim 8, comprising at least one metal oxide.

10. A magnetic recording medium comprising the laminated film according to claim 8 or 9.

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