Magnetic material target and magnetic material target assembly

Abstract

Disclosed is a magnetic material target which contains one or more elements selected from Pt, B, Ti, and Si, one or more elements selected from Gd, Ge, Sn, Te, and Hf, and an oxide, with the balance being made up of Co and selectively contained impurities, wherein: the total concentration of Co and Pt is 50 at% or more; the total concentration of B, Ti, and Si is 10 at% or more; the concentration of O is 20 at% or more; and the total concentration of Gd, Ge, Sn, Te, and Hf is 1 at% or more.

Description

Magnetic material targets and magnetic material target assemblies

[0001] The present invention relates to magnetic material targets and magnetic material target assemblies.

[0002] The layers constituting hard disk drives (HDDs) that employ perpendicular magnetic recording systems are made of materials based on ferromagnetic metals such as Co, Fe, and Ni, and the recording layers are often made of composite materials consisting of ferromagnetic alloys, such as Co-Cr, Co-Pt, and Co-Cr-Pt, which contain Co as the main component, and non-magnetic inorganic materials. Thin films for magnetic recording media such as hard disk drives are often produced by sputtering magnetic targets containing the above materials, due to their high productivity.

[0003] In general, magnetic material targets are manufactured by first crushing and mixing raw material powders, and then hot-pressing the resulting mixture to obtain a sintered body. To increase the density of the sintered body, HIP (Hot Isostatic Pressing) processing may then be performed. The sintered body thus obtained is then machined using a lathe to produce a target of a predetermined shape (Patent Documents 1 to 3).

[0004] Patent No. 6445126 Patent No. 6332869 Patent No. 6958819

[0005] As mentioned above, composite materials consisting of a ferromagnetic alloy primarily composed of Co and a non-magnetic inorganic material are useful as recording layers for HDDs, and are sputter-deposited by HDD media manufacturers to form thin films with a granular structure in which magnetic particles are separated by oxide grain boundaries. In recent years, research has been conducted on various additive oxides for perpendicular magnetic recording media that use Co as the primary magnetic particle, and the development of new magnetic material targets containing oxides of new elements is eagerly awaited.

[0006] SUMMARY OF THE INVENTION Accordingly, an object of embodiments of the present invention is to provide a novel magnetic material target and magnetic material target assembly having magnetic properties.

[0007] The above problems are solved by the present invention, which is specified as follows: 1. A magnetic material target comprising one or more of Pt, B, Ti, and Si, one or more of Gd, Ge, Sn, Te, and Hf, and an oxide, with the balance being Co and selectively contained impurities, wherein the total concentration of Co and Pt is 50 at% or more, the total concentration of B, Ti, and Si is 10 at% or more, the concentration of O is 20 at% or more, and the total concentration of Gd, Ge, Sn, Te, and Hf is 1 at% or more. 2. The magnetic material target according to 1 above, wherein the total concentration of Gd, Ge, Sn, Te, and Hf is 1 to 5 at% or more. 3. The magnetic material target according to 1 above, wherein the total concentration of Gd, Ge, Sn, Te, and Hf is 1 to 3 at%. 4. 4. The magnetic material target according to any one of 1 to 3 above, wherein the oxide further contains one or more oxides of elements selected from Al, Si, Ba, Be, Ca, Ce, Cr, Co, Dy, Er, Eu, Ga, Ho, Li, Mg, Mn, Nb, Nd, Pr, Sc, Sm, Sr, Ta, Tb, Ti, V, Y, Zn, and Zr. 5. A magnetic material target assembly comprising: the magnetic material target according to any one of 1 to 4 above; and a backing plate bonded to the magnetic material target.

[0008] According to embodiments of the present invention, novel magnetic material targets and magnetic material target assemblies having magnetic properties can be provided.

[0009] 1 is a graph showing the results of a test of the gas pressure dependency of saturation magnetization (Ms) for Examples 1 to 5.

[0010] Next, the embodiments for carrying out the present invention will be described in detail. It should be understood that the present invention is not limited to the following embodiments, and that appropriate design changes, improvements, etc. may be made based on the ordinary knowledge of those skilled in the art without departing from the spirit of the present invention.

[0011] <Magnetic Material Target> The shape of the magnetic material target according to the embodiment of the present invention is not particularly limited, and may be a flat plate (including a disk or rectangular plate), a cylindrical shape, or any other shape.

[0012] The magnetic material target according to the embodiment of the present invention contains one or more of Pt, B, Ti, and Si, one or more of Gd, Ge, Sn, Te, and Hf, an oxide, and the balance is Co and selectively contained impurities. By using the magnetic material target according to the embodiment of the present invention as a sputtering target, it is possible to produce a thin film for a magnetic recording medium such as a hard disk drive (HDD).

[0013] In the magnetic material target according to the embodiment of the present invention, the total concentration of Co and Pt is 50 at% or more. When the total concentration of Co and Pt in the magnetic material target is 50 at% or more, the magnetic properties are improved in that a certain level of magnetization can be ensured. There is no particular upper limit to the total concentration of Co and Pt in the magnetic material target, but from the viewpoint of ensuring grain boundary material, 90 at% or less is preferable. Furthermore, the total concentration of Co and Pt in the magnetic material target is more preferably 50 to 85 at%, and even more preferably 50 to 80 at%.

[0014] In the magnetic material target according to the embodiment of the present invention, the total concentration of B, Ti, and Si is 10 at% or more, and the concentration of O is 20 at% or more. With such a configuration, B, Ti, Si, and O tend to form oxide grain boundaries with a granular structure in which magnetic grains are separated by oxide grain boundaries, making it possible to obtain a preferable magnetic thin film. In the magnetic material target according to the embodiment of the present invention, the total concentration of B, Ti, and Si is preferably 10 to 15 at%, and more preferably 10 to 13 at%. In the magnetic material target according to the embodiment of the present invention, the concentration of O is preferably 20 to 35 at%, and more preferably 25 to 30 at%.

[0015] The magnetic material target according to an embodiment of the present invention contains one or more of Gd, Ge, Sn, Te, and Hf. These elements may be contained as a single element, an alloy, or an oxide. Examples of oxides of Gd include Gd2O3. Examples of oxides of Ge include GeO2. Examples of oxides of Sn include SnO2. Examples of oxides of Te include TeO2. Examples of oxides of Hf include HfO2. Hereinafter, how to determine whether Gd is contained in the form of an oxide in the magnetic material target according to an embodiment of the present invention will be described. First, the magnetic material target is cut and the cross section is mirror-polished to obtain a sample for microstructure observation. More specifically, the cross section of the magnetic material target is polished sequentially using abrasive cloths ranging from P80 to P2000, and finally buffed with aluminum oxide abrasive grains having a particle size of 0.3 μm to obtain a sample for microstructure observation having a polished cross section. At this time, aluminum oxide and granular polishing debris adhering to the polished surface are thoroughly removed by washing. Subsequently, element mapping is performed on the sputtered surface of the mirror-polished sample by performing WDX mapping analysis (Wave Length-Dispersive X-ray Mapping Spectroscopy) in a 50 μm × 50 μm field of view using an FE-EPMA (Field Emission-Electron Probe Micro Analysis). The WDX mapping analysis in a 50 μm × 50 μm field of view using the FE-EPMA is performed at an acceleration voltage of 15.0 kV and an irradiation current of 2.0 × 10 -8This can be performed by performing a stage scan under the condition of A. At this time, if the areas where the detected intensities of Gd and O are high coincide with each other, it is considered that the Gd is mostly present in the sintered body as an oxide. Therefore, Gd where the detected intensities are high coincide with O is determined to be contained in the form of Gd oxide. Furthermore, in the magnetic material target according to the embodiment of the present invention, whether Ge, Sn, Te, Hf, Si, or Ti is contained in the form of an oxide can be determined in the same manner as the above-described method for determining Gd oxide. Furthermore, in addition to oxides of Gd, Ge, Sn, and Te, the oxides may further contain one or more oxides of elements selected from Al, Si, Ba, Be, Ca, Ce, Cr, Co, Dy, Er, Eu, Ga, Ho, Li, Mg, Mn, Nb, Nd, Pr, Sc, Sm, Sr, Ta, Tb, Ti, V, Y, Zn, and Zr in order to further improve the magnetic properties.

[0016] In the magnetic material target according to the embodiment of the present invention, the total concentration of Gd, Ge, Sn, Te, and Hf is 1 at% or more. Gd, Ge, Sn, Te, and Hf contribute to the formation of magnetic grains and oxide grain boundaries with a granular structure, and are therefore considered to contribute to the formation of a thin film having magnetic properties. The total concentration of Gd, Ge, Sn, Te, and Hf in the magnetic material target is preferably 1.2 at% or more. The total concentration of Gd, Ge, Sn, Te, and Hf in the magnetic material target may be 1 to 5 at%, 1 to 3 at%, or 1 to 2 at%.

[0017] The remainder of the magnetic material target according to the embodiment of the present invention may or may not contain impurities. Examples of such impurities include metal elements such as Fe, Ni, Cu, Zr, Al, W, V, Zn, and Ta, as well as simple substances or compounds of elements such as C or N from gas components such as carbon dioxide and nitrogen in the atmosphere. The impurity content of the remainder of the magnetic material target according to the embodiment of the present invention may be 0.5 mol% or less, or 0.15 mol% or less. Furthermore, the impurities can be analyzed by collecting an analytical sample from the magnetic material target and using infrared absorption spectroscopy, an ICP optical emission spectrometer, GDMS (glow discharge mass spectrometry), or the like. The amount and shape of the analytical sample vary depending on the analytical method used, and the optimal amount and shape for each method can be selected.

[0018] <Magnetic Material Target Assembly> The magnetic material target according to the embodiment of the present invention may be bonded to a backing plate as needed to form a magnetic material target assembly. The magnetic material target assembly can be mounted in a sputtering apparatus for use. Indium or indium tin can be used as the brazing material. The magnetic material target according to the embodiment of the present invention may be mounted directly in a sputtering apparatus for use without using a backing plate. The material of the backing plate is not particularly limited, and examples thereof include Cu, Ti, Mo, and alloys containing at least one of these (e.g., Cu-Ni-Si alloys (e.g., C18000, etc.), CuZn alloys, and CuCr alloys). The material of the backing plate preferably has high thermal conductivity, and from this perspective, Cu is suitable.

[0019] <Method for manufacturing a magnetic material target> A method for manufacturing a magnetic material target according to an embodiment of the present invention will be described in detail below. The magnetic material target according to an embodiment of the present invention can be manufactured by a powder sintering method. First, powders of the respective metal elements are prepared. Alternatively, alloy powders of these metals (e.g., Co-Pt powder) may be used instead of the powders of the respective metal elements. In particular, it is preferable to use Co powder, Pt powder, BO powder, TiO powder, SiO powder, CoO powder, GdO powder, GeO powder, SnO powder, TeO powder, HfO powder, etc. The 50% cumulative volume particle size D50 (average particle size D50) of each raw material powder can be as follows: Co powder: 1 to 10 μm, Pt powder: 1 to 10 μm, BO powder: 0.1 to 5 μm, TiO powder: 0.5 to 5 μm, SiO powder: 1 to 50 μm, CoO powder: 1 to 50 μm, GdO powder: 1 to 50 μm, GeO powder: 1 to 50 μm, SnO powder: 1 to 50 μm, TeO powder: 1 to 50 μm, and HfO powder: 1 to 50 μm. The purity of these raw material powders is usually 2N (99% by mass) or higher, preferably 3N (99.9% by mass) or higher, and more preferably 4N (99.99% by mass) or higher. If the purity is lower than 2N, the sintered body will contain a large amount of impurities, which can cause problems such as the failure to obtain the desired physical properties (for example, generation of particles due to arcing). These raw material powders can be appropriately prepared based on the composition and purity of the desired sintered body.

[0020] These metal powders are then weighed to obtain the desired composition and mixed using a mixer that also serves as a pulverizer. Non-magnetic particles may also be mixed with the metal powder at this stage. Mixing devices such as a ball mill or mortar can be used, but it is preferable to use a powerful mixing method such as a ball mill. Considering the problem of oxidation during mixing, it is preferable to mix the materials in an inert gas atmosphere or in a vacuum.

[0021] Here, the mixing is carried out by carrying out primary mixing, followed by sieving, and then secondary mixing, and the primary mixing is preferably carried out for 5 to 30 hours, and the secondary mixing is preferably carried out for 5 to 30 hours.

[0022] The mixed powder thus obtained is molded and sintered using a hot press to produce a sintered body. The molding and sintering method is not limited to hot pressing; plasma discharge sintering and hot isostatic sintering can also be used. The sintering conditions can be 650 to 1400°C for 0.5 to 12 hours.

[0023] The sintered body is then removed from the hot press and subjected to HIP (Hot Isostatic Pressing). HIP is an effective method for increasing the density of the sintered body. The holding temperature during HIP is 650-1100°C, the holding time is 0.5-12 hours, and the pressure is 100 MPa or more. The sintered body thus obtained is then machined into the desired shape on a lathe to produce a magnetic material target.

[0024] <Film formation method using a magnetic material target> Using the magnetic material target according to the embodiment of the present invention, it is possible to form a thin film that mainly constitutes a magnetic recording medium. Specifically, a sputtering device is used to sputter the surface of the magnetic material target with accelerated argon ions, causing particles (sputtered particles) to be emitted from the magnetic material target, and the sputtered particles are deposited on the surface of a substrate previously positioned opposite the target, thereby forming a thin film on the surface of the substrate. Sputtering conditions can be set appropriately depending on the desired film thickness, composition, etc.

[0025] Examples of the present invention are given below, but these examples are provided for a better understanding of the present invention and its advantages, and are not intended to limit the invention.

[0026] Example 1 A magnetic material target according to Example 1 was manufactured by the following manufacturing method. As raw material powders, 3N (99.9 mass%) Co powder, Pt powder, BO powder, TiO powder, SiO powder, CoO powder, and GdO powder were prepared and weighed to have a composition of Co-Pt-B-Ti-Si-Gd-O (Pt 10-20 at%, B 5-10 at%, Ti 1-5 at%, Si 1-5 at%, Gd 0.5-7 at%, O 25-30 at%, Co (balance)). The raw material powders were prepared so that the total composition was 100 at%. The 50% cumulative volume particle size D50 (average particle size D50) of the raw material powders was as follows: Co powder: 4 μm, Pt powder: 3 μm, BO powder: 0.1-5 μm, TiO powder: 0.5-5 μm, SiO powder: 1-50 μm, CoO powder: 1-50 μm, GdO powder: 1-50 μm. Next, the weighed Co powder, Pt powder, BO powder, TiO powder, SiO powder, CoO powder, and GdO powder were placed in a ball mill pot together with milling media, and primary mixing was carried out for 10 hours, followed by secondary mixing for 10 hours, in that order.

[0027] Next, the mixed powder removed from the ball mill pot was filled into a carbon mold and hot-pressed. The hot-pressing conditions were a vacuum atmosphere, a heating rate of 300°C / hour, a holding temperature (sintering temperature) of 850°C, and a holding time (sintering time) of 2 hours. A pressure of 30 MPa was applied from the start of heating to the end of holding. After the holding, the sintered body was allowed to cool naturally in the chamber. Thereafter, the sintered body removed from the hot-pressing mold was subjected to HIP processing. The HIP processing conditions were a heating rate of 300°C / hour, a holding temperature of 850°C, and a holding time of 2 hours. The Ar gas pressure was gradually increased from the start of heating, and the sintered body was pressed at 150 MPa during holding. After the holding, the sintered body was allowed to cool naturally in the furnace. In this way, a magnetic material target according to Example 1 was produced.

[0028] Example 2 A magnetic material target according to Example 2 was manufactured by the following manufacturing method. As raw material powders, 3N (99.9 mass%) Co powder, Pt powder, BO powder, TiO powder, SiO powder, CoO powder, and GeO powder were prepared and weighed to have a composition of Co-Pt-B-Ti-Si-Ge-O (Pt 10-20 at%, B 5-10 at%, Ti 1-5 at%, Si 1-5 at%, Ge 0.5-7 at%, O 25-30 at%, Co (balance)). The raw material powders were prepared so that the total composition was 100 at%. The 50% cumulative volume particle size D50 (average particle size D50) of the raw material powders was as follows: Co powder: 4 μm, Pt powder: 3 μm, BO powder: 0.1-5 μm, TiO powder: 0.5-5 μm, SiO powder: 1-50 μm, CoO powder: 1-50 μm, GeO powder: 1-50 μm. Next, the weighed Co powder, Pt powder, BO powder, TiO powder, SiO powder, CoO powder, and GeO powder were placed in a ball mill pot together with milling media, and primary mixing was carried out for 10 hours, followed by secondary mixing for 10 hours, in that order.

[0029] Next, the mixed powder removed from the ball mill pot was filled into a carbon mold and hot-pressed. The hot-pressing conditions were a vacuum atmosphere, a heating rate of 300°C / hour, a holding temperature (sintering temperature) of 850°C, and a holding time (sintering time) of 2 hours. A pressure of 30 MPa was applied from the start of heating to the end of holding. After the holding, the sintered body was allowed to cool naturally in the chamber. Thereafter, the sintered body removed from the hot-pressing mold was subjected to HIP processing. The HIP processing conditions were a heating rate of 300°C / hour, a holding temperature of 850°C, and a holding time of 2 hours. The Ar gas pressure was gradually increased from the start of heating, and the sintered body was pressed at 150 MPa during holding. After the holding, the sintered body was allowed to cool naturally in the furnace. In this way, a magnetic material target according to Example 2 was produced.

[0030] Example 3 A magnetic material target according to Example 3 was manufactured by the following manufacturing method. As raw material powders, 3N (99.9 mass%) Co powder, Pt powder, BO powder, TiO powder, SiO powder, CoO powder, and SnO powder were prepared and weighed to have a composition of Co-Pt-B-Ti-Si-Sn-O (Pt 10-20 at%, B 5-10 at%, Ti 1-5 at%, Si 1-5 at%, Sn 0.5-7 at%, O 25-30 at%, Co (balance)). The raw material powders were prepared so that the total composition was 100 at%. The 50% cumulative volume particle size D50 (average particle size D50) of the raw material powders was as follows: Co powder: 4 μm, Pt powder: 3 μm, BO powder: 0.1-5 μm, TiO powder: 0.5-5 μm, SiO powder: 1-50 μm, CoO powder: 1-50 μm, SnO powder: 1-50 μm Next, the weighed Co powder, Pt powder, BO powder, TiO powder, SiO powder, CoO powder, and SnO powder were placed in a ball mill pot together with milling media, and primary mixing was carried out for 10 hours, followed by secondary mixing for 10 hours, in that order.

[0031] Next, the mixed powder removed from the ball mill pot was filled into a carbon mold and hot-pressed. The hot-pressing conditions were a vacuum atmosphere, a heating rate of 300°C / hour, a holding temperature (sintering temperature) of 850°C, and a holding time (sintering time) of 2 hours. A pressure of 30 MPa was applied from the start of heating to the end of holding. After the holding, the sintered body was allowed to cool naturally in the chamber. Thereafter, the sintered body removed from the hot-pressing mold was subjected to HIP processing. The HIP processing conditions were a heating rate of 300°C / hour, a holding temperature of 850°C, and a holding time of 2 hours. The Ar gas pressure was gradually increased from the start of heating, and the sintered body was pressurized at 150 MPa during holding. After the holding, the sintered body was allowed to cool naturally in the furnace. In this way, a magnetic material target according to Example 3 was produced.

[0032] Example 4 A magnetic material target according to Example 4 was manufactured by the following manufacturing method. As raw material powders, 3N (99.9 mass%) Co powder, Pt powder, BO powder, TiO powder, SiO powder, CoO powder, and TeO powder were prepared and weighed to have a composition of Co-Pt-B-Ti-Si-Te-O (Pt 10-20 at%, B 5-10 at%, Ti 1-5 at%, Si 1-5 at%, Te 0.5-7 at%, O 25-30 at%, Co (balance)). The raw material powders were prepared so that the total composition was 100 at%. The 50% cumulative volume particle size D50 (average particle size D50) of the raw material powders was as follows: Co powder: 4 μm, Pt powder: 3 μm, BO powder: 0.1 to 5 μm, TiO powder: 0.5 to 5 μm, SiO powder: 1 to 50 μm, CoO powder: 1 to 50 μm, TeO powder: 1 to 50 μm. Next, the weighed Co powder, Pt powder, BO powder, TiO powder, SiO powder, CoO powder, and TeO powder were placed in a ball mill pot together with milling media, and primary mixing was carried out for 10 hours, followed by secondary mixing for 10 hours, in that order.

[0033] Next, the mixed powder removed from the ball mill pot was filled into a carbon mold and hot-pressed. The hot-pressing conditions were a vacuum atmosphere, a heating rate of 300°C / hour, a holding temperature (sintering temperature) of 700°C, and a holding time (sintering time) of 2 hours. A pressure of 30 MPa was applied from the start of heating to the end of holding. After the holding, the sintered body was allowed to cool naturally in the chamber. Thereafter, the sintered body removed from the hot-pressing mold was subjected to HIP processing. The HIP processing conditions were a heating rate of 300°C / hour, a holding temperature of 750°C, and a holding time of 2 hours. The Ar gas pressure was gradually increased from the start of heating, and the sintered body was pressed at 150 MPa during holding. After the holding, the sintered body was allowed to cool naturally in the furnace. In this way, a magnetic material target according to Example 4 was produced.

[0034] Example 5 A magnetic material target according to Example 5 was manufactured by the following manufacturing method. As raw material powders, 3N (99.9 mass%) Co powder, Pt powder, BO powder, TiO powder, SiO powder, CoO powder, and HfO powder were prepared and weighed to have a composition of Co-Pt-B-Ti-Si-Hf-O (Pt 10-20 at%, B 5-10 at%, Ti 1-5 at%, Si 1-5 at%, Hf 0.5-7 at%, O 25-30 at%, Co (balance)). The raw material powders were prepared so that the total composition was 100 at%. The 50% cumulative volume particle size D50 (average particle size D50) of the raw material powders was as follows: Co powder: 4 μm, Pt powder: 3 μm, BO powder: 0.1-5 μm, TiO powder: 0.5-5 μm, SiO powder: 1-50 μm, CoO powder: 1-50 μm, HfO powder: 1-50 μm. Next, the weighed Co powder, Pt powder, BO powder, TiO powder, SiO powder, CoO powder, and HfO powder were placed in a ball mill pot together with milling media, and primary mixing was carried out for 10 hours, followed by secondary mixing for 10 hours, in that order.

[0035] Next, the mixed powder removed from the ball mill pot was filled into a carbon mold and hot-pressed. The hot-pressing conditions were a vacuum atmosphere, a heating rate of 300°C / hour, a holding temperature (sintering temperature) of 850°C, and a holding time (sintering time) of 2 hours. A pressure of 30 MPa was applied from the start of heating to the end of holding. After the holding, the sintered body was allowed to cool naturally in the chamber. Thereafter, the sintered body removed from the hot-pressing mold was subjected to HIP processing. The HIP processing conditions were a heating rate of 300°C / hour, a holding temperature of 850°C, and a holding time of 2 hours. The Ar gas pressure was gradually increased from the start of heating, and the sintered body was pressurized at 150 MPa during holding. After the holding, the sintered body was allowed to cool naturally in the furnace. In this way, a magnetic material target according to Example 5 was produced.

[0036] <Composition Analysis> Chips were collected from the magnetic material targets according to Examples 1 to 5, and the compositions of Co, Pt, B, Ti, Si, Gd, Ge, Sn, Te, and Hf were analyzed by ICP optical emission spectroscopy (Model SPS5520, manufactured by Hitachi High-Tech Corporation). Quantitative analysis of O was performed using non-dispersive infrared absorption spectroscopy (CS-444, manufactured by LECO Corporation). Table 1 shows the analyzed compositions of the magnetic material targets according to Examples 1 to 5.

[0037] <Oxides> The oxides contained in the magnetic material targets according to Examples 1 and 5 were analyzed as follows. First, the magnetic material target was cut and its cross section was mirror-polished to obtain a sample for structure observation. More specifically, the cross section of the magnetic material target was polished using abrasive cloths with grit sizes ranging from P80 to P2000 in order by the mirror polishing, and finally buffed using aluminum oxide abrasive grains with a particle size of 0.3 μm to obtain a sample for structure observation having a polished surface on its cross section. Furthermore, at this time, aluminum oxide and granular polishing debris adhering to the polished surface were thoroughly removed by washing. Subsequently, element mapping was performed on the sputtered surface of the mirror-polished sample by performing WDX mapping analysis (Wave Length-Dispersive X-ray Mapping Spectroscopy) in a 50 μm × 50 μm field of view using a FE-EPMA (Field Emission-Electron Probe Microanalysis). The WDX mapping analysis in a 50 μm × 50 μm field of view using the FE-EPMA was performed at an acceleration voltage of 15.0 kV and an irradiation current of 2.0 × 10 -8This could be carried out by performing a stage scan under the condition of A. At this time, if the areas with high detection intensities of Gd and O coincide, it is considered that most of the Gd is present in the sintered body as an oxide. Therefore, Gd whose area with high detection intensity coincides with O was determined to be contained in the form of Gd oxide. In addition, determination of whether Hf is contained in the form of Hf oxide was also carried out in the same manner as the above-mentioned method for determining Gd oxide. As a result, Gd oxide was confirmed in the magnetic material target of Example 1, and Hf oxide was confirmed in the magnetic material target of Example 5. In addition, Ti oxide and Si oxide were confirmed in the magnetic material targets of Examples 1 to 5 by the same measurement method as above.

[0038]

[0039] <Gas Pressure Dependence of Saturation Magnetization (Ms)> The gas pressure dependence of saturation magnetization (Ms) for the magnetic material targets of Examples 1 to 5 was measured using the following method. First, a Cr-Ti (6 nm), Ni-W (5 nm), and Ru (20 nm) film was formed in this order on a glass substrate using a magnetron sputtering device (C-3010 manufactured by Canon Anelva Corporation). Each of the sputtering targets described above was then sputtered at 300 W under an Ar atmosphere of 3.0 Pa to form a magnetic film with a thickness of 11 nm. A protective film of Ru (3 nm) was then formed to prevent oxidation of the magnetic film, forming each layer. The saturation magnetization (Ms) of the magnetic film obtained by the above film formation procedure was measured using a vibrating sample magnetometer manufactured by Tamagawa Seisakusho. The measurement conditions were a maximum applied magnetic field of 22 kOe in all cases. The test results are shown in FIG. 1. It can be seen from FIG. 1 that magnetic material targets having the magnetic properties were obtained for all of Examples 1 to 5.

[0040] According to one embodiment of the present invention, a novel magnetic material target having magnetic properties can be obtained, which may contribute to the advancement of thin film formation technology by sputtering used in the manufacture of magnetic recording hard disk media, etc. Therefore, one embodiment of the present invention may contribute to Goal 9 of the Sustainable Development Goals (SDGs) led by the United Nations, which is to "Build resilient infrastructure, promote inclusive and sustainable industrialization, and foster innovation."

Claims

1. A magnetic material target comprising one or more of Pt, B, Ti, and Si, one or more of Gd, Ge, Sn, Te, and Hf, and an oxide, with the remainder being Co and selectively contained impurities, wherein the total concentration of Co and Pt is 50 at% or more, the total concentration of B, Ti, and Si is 10 at% or more, the concentration of O is 20 at% or more, and the total concentration of Gd, Ge, Sn, Te, and Hf is 1 at% or more.

2. The magnetic material target according to claim 1, wherein the total concentration of Gd, Ge, Sn, Te, and Hf is 1 to 5 at %.

3. The magnetic material target according to claim 1, wherein the total concentration of Gd, Ge, Sn, Te, and Hf is 1 to 3 at %.

4. The magnetic material target according to claim 1, wherein the oxide further contains one or more oxides of elements selected from Al, Si, Ba, Be, Ca, Ce, Cr, Co, Dy, Er, Eu, Ga, Ho, Li, Mg, Mn, Nb, Nd, Pr, Sc, Sm, Sr, Ta, Tb, Ti, V, Y, Zn, and Zr.

5. A magnetic material target assembly comprising: a magnetic material target according to any one of claims 1 to 4; and a backing plate joined to the magnetic material target.

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