摘要:
A process for producing aromatic polyester which comprises mixing5 to 70 mol % (as calculated by converting the repeating unit mentioned below into one molecule) of polyester (A) with the repeating unit represented by general formula (I), ##STR1## and 95 to 30 mol % of an acyloxyl aromatic carboxylic acid (B), with 0.1 to 20 mol % based on the total amount of (A) and (B), of a diacyloxy aromatic compound (C) represented by general formula (II), ##STR2## and reacting the resulting mixture. The aromatic polyester is excellent in elasticity and mechanical strength, as well as toughness.
摘要:
A magnetic recording medium having a substrate, an under-layer formed on the substrate, a magnetic layer formed on the substrate and a protective layer formed on the magnetic layer. The magnetic layer comprises Co, Cr and Pt with a thickness being from 10 nm to 22 nm. Further, a coercivity of the magnetic layer is not less than 2000 Oe, and a fluctuation field of magnetic viscosity at a field strength equal to remanence coercivity or coercivity is not less than 30 Oe.
摘要:
A magnetic recording medium comprises an information-recording film and a ferromagnetic film on a substrate. The information-recording film is composed of, for example, an amorphous ferrimagnetic material having perpendicular magnetization. Further, the ferromagnetic film is composed of a magnetic material which has saturation magnetization larger than that of the information-recording film. Accordingly, the leak magnetic flux from the ferromagnetic film is larger than that from the information-recording film. The magnetic recording medium and a magnetic recording apparatus are obtained, which are excellent in thermal stability and which are preferred to perform super high density recording.
摘要:
A magnetic recording medium 100 comprises, on a substrate 1, a first orientation control layer 2, a second orientation control layer 4, a soft magnetic layer 6, a non-magnetic layer 8, a recording layer 12, and a carbon protective layer 14. The recording layer 12 is formed of an FePt ordered alloy phase which exhibits ferromagnetism and an FePt3 ordered alloy phase which exhibits paramagnetism. Accordingly, the magnetic coupling force, which acts between those of the FePt ordered alloy phase, is broken by the paramagnetic FePt3 ordered alloy phase. The magnetic interaction between those of the FePt ordered alloy phase is reduced, and thus the noise is reduced. Further, the high density recording can be performed, and the medium is excellent in thermal stability, because the FePt ordered alloy having high crystalline magnetic anisotropy is used for the recording layer 12.
摘要:
A magnetic recording medium comprises a magnetic recording layer 63 which is formed by using an ordered alloy containing B on a substrate 1 containing an amorphous component. A part of B in the ordered alloy is segregated in a grain boundary, and thus the magnetic interaction, which acts between magnetic grains, can be reduced. Accordingly, it is possible to form fine and minute magnetic domains in the magnetic recording layer 63, and it is possible to reduce the medium noise as well. The temperature, at which the substrate is heated during the film formation of the magnetic recording layer 63, can be suppressed to be low, because the ordering temperature for the ordered alloy containing B is lower than those of ordered alloys not containing B. Therefore, it is possible to use a substrate made of glass which is suitable for the mass production. The magnetic recording layer 63 is also excellent in thermal stability because of the use of the ordered alloy having high magnetic anisotropy. According to the present invention, it is possible to provide the magnetic recording medium for high density recording which is excellent in thermal stability and which involves low medium noise.
摘要:
A magnetic recording apparatus includes a laser light source (132), a recording magnetic head (131) and a magnetoresistive element. The recording magnetic head includes a pair of magnetic poles (100 and 101), between which the magnetoresistive element is interposed. A rotary actuator (Sa) positions the recording magnetic head at a desired track of a magnetic recording medium. A laser beam can be radiated onto the magnetic recording medium to raise the temperature of a region (302) of the medium. This region has a width of the order of the track width. The raised temperature lowers the coercive force of this region, where a recording magnetic field can be applied for high density recording. The rotary actuator may form a yaw angle (&thgr;) with a track of the magnetic recording medium. Even in this case, the recording magnetic head (131) and the reproducing element have no tracking offset from the code track. In addition, if the size of the magnetic poles (100 and 101) of the recording magnetic head are set within a predetermined range, the region (302) heated by the laser beam does not deviate from a recording magnetic field application region (303).
摘要:
A magnetic recording medium includes a non-magnetic substrate, an inorganic compound layer that is formed on the substrate and which contains a crystalline first oxide and a second oxide, and a magnetic layer that is formed on the inorganic compound layer. The crystalline first oxide comprises at least one oxide selected from cobalt oxide, chromium oxide, iron oxide and nickel oxide. The second oxide comprises at least one oxide selected from silicon oxide, aluminum oxide, titanium oxide, tantalum oxide and zinc oxide. The second oxide is present at a grain boundary of crystal grains of said first oxide. According to the present invention, magnetic recording media low in noise and diminished in thermal fluctuation and thermal decay can be obtained by making fine the crystal grains of a magnetic layer and controlling the dispersion of the grain size. Thus, magnetic recording apparatuses can be realized which can perform an ultrahigh density magnetic recording of higher than 20 Gb/in2.
摘要:
A magnetic sensor is constructed to be capable of detecting the change of tunnel current due to co-tunneling effect at a high S/N ratio by using a tunneling magneto-resistive element having a first magnetic layer of a soft magnetic material formed on a flat substrate, first and second tunnel barrier layers formed on the first magnetic layer, magnetic particles of a ferromagnetic material provided between the first and second tunnel barrier layers, and a second magnetic layer of a soft magnetic material formed on the second tunnel barrier layer so as to create tunneling junctions.
摘要:
Magnetic recording medium includes at least two layers having different magnetic anisotropy constants formed on a substrate and the perpendicular magnetic anisotropy of the second magnetic film of those magnetic films, far from the substrate surface, made equal to or larger than that of the first magnetic film near to the substrate surface, thus improving the magnetic isolation.
摘要:
Magnetic recording medium includes at least two layers having different magnetic anisotropy constants formed on a substrate and the perpendicular magnetic anisotropy of the second magnetic film of those magnetic films, far from the substrate surface, made equal to or larger than that of the first magnetic film near to the substrate surface, thus improving the magnetic isolation.