摘要:
Magnetic materials which essentially consist of a phase A with a ferromagnetic spin system and a phase B with an anti-ferromagnetic spin system, phases A and B interacting by exchange coupling, and the manufacture of such materials. The materials consist essentially of two-phase magnetic single-domain particles, with the alloy [Co.sub.x Ni.sub.1.sub.-x ] as the ferromagnetic phase A and its oxidized form [(CoO).sub.x (NiO).sub.1.sub.-x ] as the anti-ferromagnetic phase B, with values of x of 0.04 to 0.96. They are manufactured by surface oxidation of a pigment layer, which at least covers the surface but may extend deeper, having the composition of phase A, to form an oxide layer, at least 40 A thick, of the phase B, followed by heating in an inert gas atmosphere, or by reduction of a corresponding layer of phase B to a layer of phase A. Magnetic single-domain particles of this composition have a Neel temperature which varies with X. As a result, materials are obtained which have an asymmetrical hysteresis loop, attributable to exchange anisotropy, at temperatures which can be varied within wide limits in accordance with the intended use of the material.
摘要:
A process for the manufacture of magnetic materials containing a phase A with a ferromagnetic spin system, of composition Co.sub.x Ni.sub.1.sub.-x and a phase B with an antiferromagnetic spin system of composition (CoO).sub.x (NiO).sub.1.sub.-x , with values of x from 0.05 to 0.96, the phases A and B showing exchange interaction. The materials are manufactured by surface oxidation of starting materials having a ferromagnetic layer, at least on the surface but optionally extending deeper, of composition A, to produce the antiferromagnetic phase B, nitrous oxide being used as the oxidant. Magnetic materials thus obtained have an asymmetrical hysteresis loop, which manifests itself at different temperatures, namely the particular Neel temperature of the phase B, which depends on the composition of the phases which varies in accordance with the values of x.
摘要:
The invention relates to an improved apparatus for the manufacture of magnetic discs carrying very thin magnetic layers, by applying a fluid dispersion of magnetic materials in a binder mixture to rigid base discs by the spin-coating process. Above the side of the base disc which is to be provided with the magnetic layer, there are arranged means which produce an aerodynamic boundary layer above the discs during rotation of the latter. This avoids the formation of surface irregularities and of coating streaks during production of the layer by spin-coating.
摘要:
A device for magnetically orienting the magnetizable particles of magnetic recording media in a preferred direction, which media are obtained by applying a coating of anisotropically magnetic particles finely dispersed in a solution of an organic binder system and conventional additives to a non-magnetic base, and subsequently solidifying the coating, by the action, on the still fluid coating, of the magnetic fields produced by two E-shaped electromagnets arranged symmetrically with respect to, and in mirror-image relationship to, the plane of the said coating.
摘要:
The invention concerns a device for the non-destructive measurement of the remanent flux density of magnetic recording media, by recording a specific signal and reproducing the recorded signal by means of two pairs of magnetic recording and playback heads arranged opposite one another and perpendicular to the plane of the recording medium, the ratio of the distance between the individual magnetic heads of each pair of heads to the wavelength of the recorded signal being within a specific range, and the said distance being such that a magnetic recording medium is movable symmetrically between the pair of heads, a common measuring unit being associated with the playback pair. Further features of the device relate to the design of the magnetic recording and playback heads, the measuring unit and the rate at which the particular magnetic recording medium being tested moves between the pairs of heads.
摘要:
The invention relates to an improved process for the manufacture of magnetic discs carrying very thin magnetic layers, by applying a fluid dispersion of magnetic materials in a binder mixture to rigid base discs by the spin-coating process. Above the side of the base disc which is to be provided with the magnetic layer, there are arranged means which produce an aerodynamic boundary layer above the discs during rotation of the latter. This avoids the formation of surface irregularities and of coating streaks during production of the layer by spin-coating.
摘要:
A device for manufacturing magnetic recording media in which the magnetic particles in the recording layer are oriented in a preferred direction, the fluid coating applied to the base being subjected to the action of a magnetic field produced in the air gaps between the spaced apart poles of two magnetic circuits, one on each side of the coated face, arranged symmetrically with respect to the plane of the coated base, the edges of the poles adjacent to the coated base terminating in screening elements shaped in such a way that the distance between the surfaces of the screening elements facing the coated base and the coated base itself increases as the screening elements extend away from the edges of the poles. A high degree of magnetic anisotropy in the recording layer can also be obtained when the magnetic circuits are at a relatively large distance from the still fluid magnetic coating.
摘要:
The invention is directed to a tape transport mechanism for recording and playing back video signals comprising a contact winding mechanism with tape-guiding means at the capstan and a magnetic tape in which the substrate is a polyethylene terephthalate film. The coated side of the tape, during transport, is in contact with the guide surface of the guide means, and no part of the transport mechanism at which slip could occur during the tape transport is allowed to be in contact with the tape substrate. The tape is wound with its substrate on the inside and its coated side is preferably abrasive with respect to the guide surface, which latter may advantageously consist either of steel or a ceramic material. The bonding agent of the magnetic dispersion -- preferably a chromium dioxide dispersion -- may be prepared from a polyurethane/polyvinyl chloride mixture which imparts the desired hardness to the tape. The arrangement can be advantageously employed with any kind of record/playback apparatus for video signals which includes a stationary head and develops high tape advance speeds.
摘要:
A device for positioning magnetic heads over preselected tracks on magnetic disks in memory processing units, the device consisting essentially of a linear electric motor, including a stationary, partially hollow magnetic device, and of a support member and a guide member which is mounted on the latter in an axially movable manner and is provided with at least one head mount for at least one head support, wherein the support member is mounted at one end of the magnetic device and is otherwise unsupported by the chassis of the memory processing unit.
摘要:
The invention relates to a cartridge for a recording medium in tape or strip form and a transport apparatus for use with such a cartridge, both being favorably matched to one another according to the invention. The cartridge consists essentially of a housing which is composed of parts pivotally connected to one another and, in the closed position, completely encloses a roll of tape wound on a hub. In the open position of the cartridge, at least part of the roll of tape is so exposed that the roll can be rotated and the tape or strip scanned on the apparatus. The transport apparatus is provided with appropriately designed means for receiving the cartridge which, when some of its components are pivoted, swings apart the parts of the cartridge, which is placed upon the apparatus in the closed position, and thus opens the cartridge.