Circular magnetic domain devices

A cylindrical magnetic domain device includes a layer of uniaxial magnetic material having a unique easy magnetisation direction substantially normal to a major surface thereof;

• generating means for generating cylindrical magnetic domains within the said layer;
• propagation means which define at least three propagation paths in which the generated cylindrical magnetic domains can be caused to propagate;
• and switching means for effecting the transfer of the propagating cylindrical magnetic domains from one of said propagation paths to at least another one of the said propagation paths, the switching means including at least three magnetically permeable elements formed on the said major surface and orientated relative to each other and the propagation paths in a manner such that expansion of the propagating cylindrical magnetic domains can be effected, and magnetic field impulse generating means positioned to encompass at least the central element or elements of the switching means;
• wherein the propagation means define three propagation paths;
• wherein a first one of the said magnetically permeable elements forms part of the said one of the propagation paths and the route between the said one of the propagation paths and another one of the propagation parts;
• and wherein a second one of the said magnetically permeable elements forms part of the other one of the propagation paths and is inclined at an angle relative to the other magnetically permeable elements, the angle of inclination being such that the second one of the magnetically permeable elements becomes more attractive to the propagating domain than the other magnetically permeable elements just after expansion of the domain.

A cylindrical magnetic domain device includes a layer of uniaxial magnetic material having a unique easy magnetisation direction substantially normal to a major surface thereof;

• generating means for generating cylindrical magnetic domains within the said layer;
• propagation means which define at least three propagation paths in which the generated cylindrical magnetic domains can be caused to propagate;
• and switching means for effecting the transfer of the propagating cylindrical magnetic domains from one of the said propagation paths to at least another one of the said propagation paths, the switching means including at least three magnetically permeable elements formed on the said major surface and orientated relative to each other and the propagation paths in a manner such that expansion of the propagating cylindrical magnetic domains can be effected, and magnetic field impulse generating means positioned to encompass at least the central element or elements of the switching means;
• and wherein the propagation means define four propagation paths, wherein the switching means are adapted to effect the switching and replication of two trains of cylindrical magnetic domains and wherein each of the domain trains is propagated along a separate one of first and second one of the propagation paths and is transferable by the switching means to at least one of third and fourth ones of the propagation paths.

A cylindrical magnetic domain device includes a layer of uniaxial magnetic material having a unique easy magnetisation direction substantially normal to a major surface thereof;

• generating means for generating cylindrical magnetic domains within the said layer;
• propagation means which define at least three propagation paths in which the generated cylindrical magnetic domains can be caused to propagate;
• and switching means for effecting the transfer of the propagating cylindrical magnetic domains from one of the said propagation paths to at least another one of the said propagation paths, the switching means including at least three magnetically permeable elements formed on the said major surface and orientated relative to each other and the propagation paths in a manner such that expansion of the propagating cylindrical magnetic domains can be effected, and magnetic field impulse generating means positioned to encompass at least the central element or elements of the switching means;
• wherein the impulse generating means includes a conductor shaped in the form of at least one loop which encompasses the central element or elements of the switching means;
• and wherein the impulse generating means also includes means adapted to cause a current pulse to be applied to the looped conductor when each of the propagating domains is in an expanded state, the polarity, amplitude and width of the current pulse being arranged so that the resulting magnetic field impulse causes that part of the expanded domain ecompassed by the looped conductor to collapse and to thereby produce two domains.

A cylindrical magnetic domain device includes a layer of uniaxial magnetic material having a unique easy magnetisation direction substantially normal to a major surface thereof;

• generating means for generating cylindrical magnetic domains within the said layer;
• propagation means which define at least three propagation paths in which the generated cylindrical magnetic domains can be caused to propagate;
• and switching means for effecting the transfer of the propagating cylindrical magnetic domains from one of the said propagation paths to at least another one of the said propagation paths, the switching means including at least three magnetically permeable elements formed on the said major surface and orientated relative to each other and the propagation paths in a manner such that expansion of the propagating cylindrical magnetic domains can be effected, and magnetic field impulse generating means positioned to encompass at least the central element or elements of the switching means;
• wherein the impulse generating means includes a conductor shaped in the form of at least one loop which encompasses the central element or elements of the switching means;
• and wherein the impulse generating means also includes means adapted to cause a current pulse to be applied to the looped conductor before a propagating domain is expanded, the polarity, amplitude and width of the current pulse being arranged so that the resulting magnetic field impulse prevents expansion of the domain.