Abstract: A semiconductor device includes a substrate; a first nitride semiconductor layer provided over the substrate and having a nitride-polar surface; a gate electrode provided over the first nitride semiconductor layer; and a semiconductor layer provided on the first nitride semiconductor layer and only under the gate electrode, and exhibiting a polarization.

Abstract: A compound semiconductor device includes: a substrate; an electron transit layer formed over the substrate; an electron supply layer formed over the electron transit layer; and a buffer layer formed between the substrate and the electron transit layer and including AlxGa1-xN(0?x?1), wherein the x value represents a plurality of maximums and a plurality of minimums in the direction of the thickness of the buffer layer, and the variation of x in any area having a 1 nm thickness in the buffer layer is 0.5 or less.

Abstract: A compound semiconductor device including: a substrate; an electron transit layer formed on and above the substrate; and an electron supply layer formed on and above the electron transit layer, wherein a first region or regions having a smaller thermal expansion coefficient than the electron transit layer and a second region or regions having a larger thermal expansion coefficient than the electron transit layer are mixedly present on a surface of the substrate.

Abstract: A manufacturing method of a magnetic recording medium, the magnetic recording medium having a structure where plural magnetic recording areas and isolation areas in a magnetic recording layer are formed on a non-magnetic substrate, the isolation areas being configured to magnetically isolate the magnetic recording areas, the manufacturing method includes a step of forming the magnetic layer on the non-magnetic substrate, the magnetic layer being made of a hard magnetic material having a magnetic coercive force whereby magnetic recording is impossible; and a step of performing ion implantation partially at positions corresponding to the plural magnetic recording areas of the magnetic layer so that the magnetic recording areas are formed by reducing the magnetic coercive force in the positions of the ion implantation to a magnetic-recordable magnetic coercive force, and allowing the isolation areas to maintain the magnetic coercive force whereby magnetic recording is impossible.

Abstract: A compound semiconductor device including: a substrate; an electron transit layer formed on and above the substrate; and an electron supply layer formed on and above the electron transit layer, wherein a first region or regions having a smaller thermal expansion coefficient than the electron transit layer and a second region or regions having a larger thermal expansion coefficient than the electron transit layer are mixedly present on a surface of the substrate.

Abstract: A compound semiconductor device includes: a substrate; an electron transit layer formed over the substrate; an electron supply layer formed over the electron transit layer; and a buffer layer formed between the substrate and the electron transit layer and including AlxGa1-xN(0?x?1), wherein the x value represents a plurality of maximums and a plurality of minimums in the direction of the thickness of the buffer layer, and the variation of x in any area having a 1 nm thickness in the buffer layer is 0.5 or less.

Abstract: A manufacturing method of a magnetic recording medium, the magnetic recording medium having a structure where plural magnetic recording areas and isolation areas in a magnetic recording layer are formed on a non-magnetic substrate, the isolation areas being configured to magnetically isolate the magnetic recording areas, the manufacturing method includes a step of forming the magnetic layer on the non-magnetic substrate, the magnetic layer being made of a hard magnetic material having a magnetic coercive force whereby magnetic recording is impossible; and a step of performing ion implantation partially at positions corresponding to the plural magnetic recording areas of the magnetic layer so that the magnetic recording areas are formed by reducing the magnetic coercive force in the positions of the ion implantation to a magnetic-recordable magnetic coercive force, and allowing the isolation areas to maintain the magnetic coercive force whereby magnetic recording is impossible.

Abstract: A disclosed method for manufacturing a magnetic recording medium includes a first step of forming a magnetic recording film on a non-magnetic substrate and a second step of forming, in the magnetic recording film, a magnetic recording region which is magnetically recordable and an isolation region which is magnetically non-recordable and includes a first isolation-region portion and a second isolation-region portion. The second step includes the sub-steps of performing first ion implantation on the magnetic recording film to form the first isolation-region portion along a boundary of the isolation region to be formed with the magnetic recording region to be formed; and performing second ion implantation on the magnetic recording film to form the second isolation-region portion in the surface of the isolation region to be formed.

Abstract: A soft magnetic thin film in which the recording magnetic field in the perpendicular direction can be preferentially intensified and sharply controlled when the thin film is applied to a perpendicular magnetic recording medium is provided. This soft magnetic thin film can be obtained by immersing a substrate into an electroless plating bath that contains a Co ion, Fe ion, and Ni ion as metal ions, as well as a completing agent and a boron-type reducing agent, wherein the content ratios of the metal ions on the mole basis are 0.15? (Ni ion amount/the amount of total metal ions) ?0.40, 0.50? (Co ion amount/the amount of total metal ions) ?0.80, and 0.05? (Fe ion amount/the amount of total metal ions) ?0.15; and carrying out electroless plating in a magnetic field in a range of 5-2,000 Oe given in a direction parallel to the surface of said substrate.

Abstract: The magnetic recording medium comprises a first recording layer 16, a second recording layer 20 forming ferromagnetic coupling with the first recording layer, and an intermediate layer 18 formed between the first recording layer 16 and the second recording layer 20 and including non-magnetic layers 18a, 18b formed between the first recording layer 16 and the non-magnetic layer 18b and between the non-magnetic layer 18b and the second recording layer 20. Thus, the reproduction output of the vertical magnetic recording medium can be improved. The constitutions of the ferromagnetic layer and the non-magnetic layer of the intermediate layer are suitably controlled, whereby the S/N ratio of the vertical magnetic recording medium can be also improved.

Abstract: A soft magnetic thin film in which the recording magnetic field in the perpendicular direction can be preferentially intensified and sharply controlled when the thin film is applied to a perpendicular magnetic recording medium is provided. This soft magnetic thin film can be obtained by immersing a substrate into an electroless plating bath that contains a Co ion, Fe ion, and Ni ion as metal ions, as well as a complexing agent and a boron-type reducing agent, wherein the content ratios of the metal ions on the mole basis are 0.15?(Ni ion amount/the amount of total metal ions) ?0.40, 0.50?(Co ion amount/the amount of total metal ions) ?0.80, and 0.05?(Fe ion amount/the amount of total metal ions) ?0.15; and carrying out electroless plating in a magnetic field in a range of 5-2,000 Oe given in a direction parallel to the surface of said substrate.

Abstract: A perpendicular magnetic recording medium including a substrate, a metal base layer formed on the substrate, a soft magnetic layer formed on the metal base layer by electroless plating and having an axis of easy magnetization in the in-plane direction of the substrate, and a magnetic recording layer formed on the soft magnetic layer and having an axis of easy magnetization in a direction perpendicular to the surface of the substrate. The metal base layer is formed of an alloy containing at least one element selected from the group consisting of Co, Ni, and Fe, and has a coercivity of 3 oersteds (Oe) or less. The soft magnetic layer has a thickness of 100 to 600 nm.

Abstract: A thin film magnetic head comprising a substrate, a lower magnetic pole provided on the substrate, a write gap layer located on the lower magnetic pole, and an upper magnetic pole located on the gap layer, the upper magnetic pole including a plating base layer in contact with the gap layer, wherein the plating base layer of the upper magnetic pole is made of a magnetic film having a saturation magnetic flux density of 1.2 T or larger. The thin film magnetic head has an increased recording density, and is adapted to recording at an increased frequency.

Abstract: A thin film magnetic head comprising a substrate, a lower magnetic pole provided on the substrate, a write gap layer located on the lower magnetic pole, and an upper magnetic pole located on the gap layer, the upper magnetic pole including a plating base layer in contact with the gap layer, wherein the plating base layer of the upper magnetic pole is made of a magnetic film having a saturation magnetic flux density of 1.2 T or larger. The thin film magnetic head has an increased recording density, and is adapted to recording at an increased frequency.

Abstract: A magnetic thin film forming method forms a magnetic thin film on a conductive film by electroplating using a plating bath containing Ni ions, Fe ions, Mo ions and an organic acid. A concentration of the organic acid in the plating bath is 3-20 times a concentration of the Mo ions in the plating bath. An organic acid concentration in the plating bath versus an Mo ion concentration of the plating bath is set to be a suitable value, whereby an Mo mixed amount in the magnetic thin film can be set to be a suitable value. Accordingly, a magnetic thin film having a large specific resistance value and good magnetic characteristics can be formed.