MXPA04009307A

MXPA04009307A - Data storage device.

Info

Publication number: MXPA04009307A
Application number: MXPA04009307A
Authority: MX
Inventors: Paul Cowburn Russell
Original assignee: Eastgate Invest Ltd
Priority date: 2002-03-27
Filing date: 2003-03-25
Publication date: 2005-07-05
Also published as: TW200306536A; OA12989A; NO20043958L; JP4463564B2; CN1656568A; NZ535781A; YU91604A; TWI310938B; MY135448A; HK1070982A1; EA006289B1; GB0207160D0; IS7506A; WO2003083874A8; CN100452243C; EA200401263A1; JP2006504210A; PL373815A1; HRP20040884A2; CU23099A3

Abstract

A data storage device for storing digital information in a readable form is described made up of one or more memory elements, each memory element comprising a planar magnetic conduit capable of sustaining and propagating a magnetic domain wall formed into a continuous propagation track. Each continuous track is provided with at least one and preferably a large number of inversion nodes whereat the magnetisation direction of a domain wall propagating along the conduit under action of a suitable applied field, such as a rotating magnetic field, is changed.

Description

DATA STORAGE DEVICE FIELD OF THE INVENTION The present invention relates to a data storage device for storing digital information such as computer files, digital music, digital video, etc. In particular, the invention relates to a data storage device in which data can be written and from which said data can be read an unlimited number of times.

BACKGROUND OF THE INVENTION In recent years, a variety of data storage devices have become available that employ a range of media for a range of digital data storage applications. Data storage devices are designed and adapted to some of a variety of operational characteristics, including capacity, access speed, ability to write / rewrite, ability to retain stable data over time (with or without power ), size, robustness, portability and the like. The known data storage devices include magnetic tape storage, storage on magnetic hard drives and storage on optical discs. All offer advantages of good storage capacity and relatively fast data access, and all can be adapted to write and rewrite available data. All require moving parts in the form of electromechanical or optical readers. This may limit the extent to which devices incorporating said data storage means can be miniaturized, and limit the use of the device in high vibration environments. Although in each case the surface medium is the key to data storage, the mechanisms involved require careful control of the properties as well as any supporting substrates. Therefore, said devices have to be of a carefully controlled construction. In addition, they all require that the reader have access to the surface of the device, which may imply limitations on the design freedom for the device. An object of the present invention is to provide an alternative digital data storage device that offers versatility in alternative situations, in particular for example that can be miniaturized, and / or that can be incorporated into other devices such as smart cards, plates of identification and patches or the like, and / or that can be incorporated in flexible substrates, and / or that can be used in high vibration environments, and / or that is of a simple / low cost manufacture, etc. A particular object of the invention is to provide a data storage device that in a compact and effective way stores digital data and provides that data can be written to the invention and that it can be read an unlimited number of times.

SUMMARY OF THE INVENTION Therefore, according to the invention a data storage device for storing digital information (such as computer files, digital music, digital video, etc.) in a readable form comprises one or more, and in particular a plurality of memory elements, each memory element comprises a flat magnetic conduit that has the ability to sustain and propagate a magnetic domain wall formed in a continuous propagation channel, wherein each continuous channel is provided with at least one and, opc i nally a plurality, and in particular a large number of inversion nodes in which the direction of magnetization of a domain wall that propagates along the conduit under the action of a suitable applied field is moed and in particular substantially invested. Each conduit is formed in a continuous propagation channel. Conveniently, a conduit is formed in a closed loop to comprise said continuous propagation channel. Said loop is provided with at least one andoptionally a plurality and, in particular, a large number of investment nodes. The data has the ability to pass around the closed loop according to the mechanism mentioned below. In a variant, the magnetic conduit does not form a complete closed loop of inversion nodes, but rather a linear chain of inversion nodes with means for transferring data between the two ends. of the same for the data to continue, having the ability to circulate around a loop-apparently closed, for example comprising a data writing facility at one end of the string and a data reading facility at the other end of the string. chain, and additional circuitry to power the data return electronically from the output of the chain to the input of the chain. Conveniently, the inversion nodes comprise features in the structure and shape of the conduit that are adapted to cause a change in the direction of magnetization, and preferably a substantial reversal in the direction of magnetization, of a. domain that propagates through it under the action of a convenient applied field, such as a directionally varying and in particular rotating magnetic field. However, it is necessary that the direction of the duct and, therefore, the direction of propagation of the domain wall varied without there being strong discontinuities at any point. Therefore, the conduit in the region of and comprising the inversion node must have such configuration characteristics to cause a change in the direction of magnetization, and preferably a substantial reversal in the direction of magnetization, of a domain that is propagates through it but without any specific acute variation in the direction of propagation. In a preferred embodiment, an inversion node comprises a substantial inversion of the magnetization direction in the inversion node. Preferably, the inversion node comprises a portion in the one direction change away from the initial path and a new subsequent change in the direction to the initial path is provided in the conduit so that a direct propagation path through the path is not possible. of the deviation portion. In particular, the deviations comprise deviations of 90 ° from the initial trajectory. For the reasons mentioned, deviations from the initial path of preference occur gradually over a distance along the conduit channel. For example, the inversion node comprises a cylindrical portion within the loop structure of the conduit, in particular internally directed, or a topological equivalent of said structure. Preferably, in each loop a plurality of said cycloidal portions is provided. Therefore, a device according to the invention preferably comprises a number of magnetic conduits formed in closed loops, wherein each comprises a plurality of cycloids which serve to make abrupt direction reversals in a magnetization direction of a wall. domain that passes through it and that therefore serve as inversion points for the domain walls as they propagate along the conduit of the invention by a suitable pulse field. Preferably, each cycloid has a rotating radius that is on the scale of three to ten times the width of the conduit. Preferably, the cycloid is one that can produce a substantial change, for example a substantial 180 ° reversal, of the magnetization direction as a domain wall passes therethrough. According to the present invention, the magnetic conduit needs to have an architecture that has the ability to sustain and propagate a domain wall under the action of a control field. Typically, the magnetic conduit can be formed as a continuous channel of magnetic material. Thus, according to the invention, the loops · in the device preferably comprise magnetic cables, in particular magnetic cables generally flat in a suitable substrate. Therefore, the data storage device uses a number of flat magnetic conduits and, in particular, magnetic cables which are preferably configured in closed cycloid loops. In particular, the invention employs magnetic nanoscale technology, the device comprises a number of flat magnetic nanowires preferably configured in a plurality of closed cycloid loops. Flat magnetic nanowires preferably have less than 1 μp? of width and are formed on any suitable substrate. Width is a balance between the improved storage capacity of devices that employ narrower nanoscale cables and manufacturing costs as well as complexities. However, devices incorporating cables above a mine are unlikely to be effective, and 50 nm is a lower limit that is probably practical in terms of cost-effective practicality for current cable formation techniques. It should be emphasized that it is not a limit of "technical effect, and that improved manufacturing techniques could produce additional miniaturized devices that include the practical part of the invention." The cables are deposited on a substrate in the form of a thin layer of magnetic material. The thickness of the cable is optimized for optimum performance of the device, and by far it is a function of width.In particular, the thickness of the cable is generally about 1 / 40th of the width of the cable.The thickness of the cable is generally It is not less than 2 nm, and preferably not less than 3 nm In practice, cables are unlikely to be more than 25 nm thick.The cables can be manufactured by optical lithography, X-ray lithography, printing micro contact, e-ray lithography, deposition through a shadow mask or by some other suitable method.The cables are made of a magnetic material such as rmalloy (NieoFe2o) or CoFe or some other soft magnetic material. The data storage device incorporating inversion nodes as described above is subject to the application of a suitable directionally variable variant magnetic field and in particular a rotating magnetic field in an operation manner which is described in greater detail below, which provides the investment node with a memory function. The provisioning of a plural arrangement of loops, wherein each incorporates one or more inversion nodes, allows a device according to the invention to store data serially in a ring. The data can be written to a device according to the invention and said data can be read an unlimited number of times. Unlike storage on magnetic tape or magnetic hard disk storage, the invention does not require moving parts. In t consequence, it can be easily miniaturized and can be used in high vibration environments. The principle of the invention is very simple, and manufacturing costs can be kept low. Furthermore, no energy is required to retain the data in the memory of the invention when it is not in use. The invention uses a number of magnetic conduits such as flat magnetic cables. Flat cables are formed in a certain substrate, but unlike microelectronic memory, this substrate plays no role in the electronic or magnetic operation of the device, essentially serving only to provide mechanical support. You can still use conventional silicon substrates, but since no substrate functionality is required, you can also use materials other than silicon, such as glasses or plastics. Examples include polyimide such as Kapton, polyethylene terephthalate or Mylar type materials, acetate, polymethyl methacrylate or others. The advantage of plastic substrates is their low cost and the simplicity of their manufacture, they also offer the potential for mechanical flexibility that makes the invention suitable for integration into plastic cards such as Smart Cards or clothes Because mechanical access to the surface of the invention is not required, as is required with compact disc, magnetic tape and magnetic hard disk storage, a large number of substrates can be stacked one on top of the other to form a cube of three-dimensional memory. The regional storage density of the invention is moderate, being higher than the magnetic tape but smaller than the magnetic hard drives. The speeds for reading and writing data can be very high if required, and even higher than the speeds of the hard drives. However, the invention stores serial data in. a ring, so that the time of access to a given data block with probability could be relatively slow, making the invention be of limited mobility as a direct replacement of the primary hard drive in computers .

The international patent application PCT / GBOl / 05072 applies and develops some of the principles of the Cowburn and Welland paper referred to above to describe how digital logic circuits could be constructed from point chains at nanometric scale of material magnetic, or flat magnetic cables at nanometric scale. In particular, a magnetic access port NOT shown in FIG. 1 of the present invention is described. In Figure 1, the arrows represent the direction of magnetization within the narrow strips of magnetic material that form the access port. The central structure of the access port reverses the direction of the magnetization entering from the left. In practice, the gate will be placed in a magnetic field, whose vector rotates in the plane of the device over time. Although the device of the invention is not limited by any theory of operation, it can be seen that due to the anisotropy of the magnetic form, the magnetization in the cable is generally confined to lie along the long axis of the cable. This means that there are two possible magnetization directions and that therefore there is a natural binary representation. A change in the direction of magnetization is mediated by a magnetic domain wall that extends along the cable through the applied field. The fact that the applied field rotates means that the domain walls can be carried around the corners. According to the invention, a gate NOT similar to the one described above can be manufactured by a suitable method. Ideally, for current purposes, the shape of the gate is slightly modified compared to that shown in Figure 1, to have a cycloidal shape. The output of the gate is again connected to its input using a suitable magnetic conduit, such as a flat magnetic cable to form a closed loop. An arrangement of said loops forms the device of the invention in accordance with this preferred embodiment, which comprises flat magnetic nanowires formed in large closed loops of cycloids connected in series to form chains of magnetic NOT gates. The output of the last NOT gate in each chain is fed back into the input of the first NOT gate by a flat magnetic cable to form a closed loop for the data stream to circulate around. The cycloids serve as investment nodes to propagate the domain walls as they propagate through nanowires under the action of a suitable rotating operating field, in the manner noted above and which will be described in more detail below. The inverted output only appears after a time delay equal to one half of the period of the rotated applied field / which causes each inversion node to appear as a single-bit memory cell or tilting circuit. Therefore, the cycloid loops have the same memory function as a circular serial change recorder, and can serve as a data storage device according to the invention. According to a further aspect of the invention, there is provided a data storage system comprising one or more elements of the device as described above and further comprising a magnetic field impeller to provide a controlled time controlled magnetic field . The magnetic field impeller is preferably configured so that the driven field is applied simultaneously to all the cycloids in a given loop and can be applied simultaneously to all the loops in the system. This provides a distinctive feature of the present system in operation. The magnetic field is applied to the entire loop at one time so that all the data bits advance together, instead of only advancing locally under the writing head as would be the case with the storage of conventional magnetic data. You can contemplate any suitable field. Preferably, the magnetic field impeller provides a controlled magnetic field which · consists of two orthogonal fields operating in a predetermined sequence, preferably alternately, and more preferably forming a synchronization field in one direction in the sense of clock hands or counterclockwise. With the use of said system, data may be stored in the storage device (s) according to the first aspect of the invention. The system can also comprise inputs and / or outputs of data and / or electrical suitable to allow *. That the device of storage of data be used in a storage of memory and in systems of recovery. An example of the operation of a magnetic data storage device in accordance with the principles of the invention will now be described by way of example with reference to Figures 2 to 8.

BRIEF DESCRIPTION OF THE FIGURES Reference is made to Figures 1 to 8 of the accompanying drawings by way of illustration, wherein: Figure 1 is a schematic representation of a NOT magnetic gate of prior art * (see above); Figure 2 is a NOT magnetic gate modified to be used as a data storage device according to the invention; Figure 3 is a schematic representation of the structure of the NOT gate of Figure 2 (Part A) and its effect on a domain wall that enters a point P under the action of a rotating magnetic field H; Figure 4 shows three NOT magnetic gates connected in a ring to form a 5-bit serial change recorder in Part A, and Part B shows the simple (I trace) and complex (line II) that can be forcing sequences of bits to circulate around the ring by applying a rotating magnetic field (the asterisk in Part A shows the point in the loop where the measurements shown in Part B were taken); Figure 5 shows eleven magnetic NOT gates connected in a ring to form a 13-bit serial memory in Part A, and the »·. Part B shows a simple 13-bit data stream that circulates around the loop under the action of a rotating magnetic field (the asterisk in Part A shows the point in the loop where the measurements shown in Part B were taken ); Figure 6 is a schematic illustration of the mechanism of. writing and reading data of the present invention; Figure 7 is a schematic illustration of a number of magnetic loops on the same substrate, indi-idually directed by a number of electronic loops and demultiplexers; Figure 8 is a schematic illustration of the stacking of a number of substrates, each containing a number of data loops to form a three-dimensional memory cube.

DETAILED DESCRIPTION OF THE INVENTION Figure 2 shows a NOT gate similar to Figure 1, but particularly adapted to be optimized so that the present invention has a cycloidal shape. The gate is made by focused ion beam grinding of a Permalloy film (Ni8oFe2o) 5 nm thick on a silicon substrate. Only the bright white shadow is magnetic material; Another contrast is due to the multi-step grinding process that is used during the manufacture of the gate. Figure 2a shows the gate with its output connected back to its input using a flat magnetic cable to form a closed loop. Figure 2b shows an approach of the gate structure, which has a cycloidal shape. The magneto-optical measurements at points I and II in response to an applied rotating magnetic field are shown in Figure 2c. there is a half-cycle delay between the changing input state (trace I) and the changing output state (trace II) equal to one half of the period of the applied rotating magnetic field, which corresponds to a memory function. Figure 3 provides an explanation of the inversion action of the cycloid and in particular the origin of this delay. Under conditions of low magnetic field, the direction of magnetization within the submicron ferromagnetic flat cables tends to lie along the long axis of the cable due to the strong anisotropy of the magnetic form. When two opposingly directed magnetizations are located within a cable, the realignment of successive atomic magnetic moments is not abrupt but occurs gradually over a certain distance to form a domain wall.

It is known that domain walls can propagate along straight sub-micrometric magnetic cables by applying a magnetic field parallel to the cable. In the use of the present invention, a magnetic field is applied with a vector that rotates with time, in the sample plane can be used to propagate the domain walls along magnetic cables that also change direction and turn at the corners. Rotation in the clockwise or counterclockwise direction defines the chirality of the magnetic field. A domain wall should propagate around a corner of the magnetic cable as long as the field and the corner are of the same chirality. However, the chirality of a corner depends on the direction of the propagation of the domain wall so that, within a rotating magnetic field of determined chirality, a domain wall will only have the ability to pass through a given corner in one direction. This satisfies the important requirement of any logical systems that the definitive signal flow direction must exist. The two stable magnetization directions within the sub-micrometre magnetic cables provide a natural means to represent the two logical states of Bolean and this, together with the application of a rotating magnetic field, is the basis of the operation, of each unit logic of the memo device. The cycloid illustrated in Figure 3 provides an inversion function and demonstrates the functionality of a NOT gate when it is within a suitable rotating magnetic field. Assuming that the magnetic field is rotating in a counterclockwise direction. A domain wall arriving at the terminal P '(FIG. 3B) of the junction will propagate around the first corner of the junction (FIG. 3C) and to the terminal?)' As the applied field rotates from the horizontal direction to the vertical direction. The magnetization between ?? ' and Q 'will not be continuous (3D figure). Then, as the vector of the magnetic field continues to rotate towards the opposite horizontal direction, the domain wall should propagate "| around the second corner of the junction (Figure 3E), which exists in the 'R' terminal and restore the magnetization continuous between XQ 'and R' The magnetization of the cable immediately after joining should now be reversed compared to that immediately before joining, therefore, the union should perform the desired NOT function with a field propagation delay This operation is analogous to a vehicle that reverses its direction by making a three-point turn, so there is a total half-cycle delay between the wall that reaches the entrance and that part of the exit. , we identify that this synchronous delay has an associated memory function that can be exploited by connecting a large number of NOT magnetic gates together in series and then channeling the exit of the chain of 'return to the entrance. Figure 4 shows a reduced version of the invention where three NOT gates have been connected in a chain, and the output of the chain feedback within the beginning, of the chain by a flat magnetic cable. Two different data bit sequences were programmed into the device through a specific application of magnetic fields and then the data was cycled around the loop initiating the rotating magnetic field.

The trace I of figure 4b shows a simple bit sequence cycling around the chain1: the pattern repeats every 5 cycles of the rotating field. The trace II of figure 4b shows a more complex sequence cycling around the loop, with a period of 5 cycles of the rotating field. The device effectively behaves like a 5-bit serial change recorder. The sequence of data bits takes one step to the right in each complete cycle of the rotating field. These data were obtained using a rotating field in the counterclockwise direction and therefore, the data was cycled around the magnetic ring in a counter-clockwise direction. It was found that reversing the clockwise direction of the field causes the data to reverse its direction and begin to cycle around the magnetic ring clockwise. Figure 5 shows a test of the invention using 11 NOT gates. Figure 5b shows a simple sequence of bits that is cycling around the loop with a repeating period of 13 cycles of the rotating field.

The data is written in each loop by a lithographic cable carrying current and passing over the top or bottom of the flat magnetic cable. The data is read from each | ·. loop using a fixed magnetic tunnel junction to a part of the loop or by measuring the electrical resistance of a domain wall present in one of the corners of the cable or by measuring the electrical resistance of a domain wall present in one of the NOT gates. Figure 6 shows the uses of these data input / output methods. The data is written into the loop by means of an electric lithographic cable carrying current (61) that passes over or under the ring. The data circulates around the loop in the direction of the arrow A. The data is read from the loop either by forming a magnetic tunnel junction between two electrical contacts (62) at one point of the loop (upper panel) or by applying two electrical contacts ( 63) to measure the strength of any domain wall contained within a small part of the ring (lower panel). In a variant of the present invention (which is not shown in the figure), the magnetic conduit itself does not form a closed loop of inversion nodes, but rather a linear chain of inversion nodes with an installation for writing data at one end. of the chain and an installation to read "data at the other end of the chain." In this case, external control circuitry is required to feed the data return electronically from the chain output to the chain input so that the data can continue to circulate around a seemingly closed loop.The data loops are seated in a magnetic field, whose vector rotates in the plane of the loops over time at a frequency on the scale of lHz-200 MHz. field can be constant as the field rotates, thus forming a circular geometric shape for the magnetic field vector, or it can vary, thus forming an elliptical geometric shape for the vector of the "magnetic" field. This can be achieved in small area devices by placing an electromagnetic strip line under the loops and then passing an alternating current through the strip line. In a device with a larger area, the substrate carrying the loops is placed inside a four-pole electromagnet. The magnitude of the field should be strong enough to ensure that a domain wall can be pushed all the way Ta through each NOT gate, but not strong enough that new domain walls can form a core independently of the data entry mechanism . The field that is required to push a domain wall through each NOT gate can be tuned by varying the thickness of the loops, the width of the loops and the magnetic material used to make the loops. This field should be large enough so that the device does not suffer deletions of the magnetic fields in the dispersion environment. The invention could be protected using MuMetal if the deletion of the scattering field would result in a problem. An optimized device will use 'field resistances applied in the 50-200 Oe scale. The invention may comprise a large number of data loops on a single substrate with multiplexers and smul t ip lexore s electronic which are used to direct the correct loop, as illustrated in Figure 7. A number of loops is shown between the data writing units and the multiplexers (71) and the data reading demultiplexers and the amplifiers (72). For a given application ~ an optimal balance will be found between the number of loops and the number of NOT gates in each loop. A small number of loops, each comprising a large number of NOT gates, will be very easy and inexpensive to integrate into one package but will have a tendency for the entire device to fail if a single NOT gates fail due to manufacturing defects. . Said combination will also have a prolonged data access time, since a large number of clock cycles should be expected on average so that a given data block can be cycled to the reading position. A large number of loops, where each comprises a small number of NOT gates will be very resistant to the failure of individual NOT gates (the loop containing the defective gates can be removed from the circuit without significantly reducing the overall storage capacity) and it will have a quick access time, but it will involve more read and write points (and therefore a higher cost) and it will be more complicated to integrate a large number of loops into a single 'integrated circuit package. All the figures in this document show the loops of 8 gates. This is merely figurative; In practice, each loop will contain many thousands of gates. A particular feature of the invention is that it is not limited to a two-dimensional plane when placing data loops. Unlike storage on compact disc, magnetic tape and magnetic hard disk, mechanical access to the surface of the invention is not required. The substrates can be placed on top of them to form a three-dimensional data cube, as shown in Figure 8. This has the advantage that it allows to achieve higher data storage densities. If desired, all substrates in a cube can share the same applied rotating magnetic field, thus maintaining the layers in mutual synchronization and reducing the complexity of the device. The invention can be configured for a single stream in data series, or if desired, data word streams with a multi-bit width can be stored using several rings or layers in parallel. Due to the low access time, the invention is not convenient as a replacement for the primary hard disk in computers. However, you may find application in some of the following situations, as well as in others. - Temporary storage of digital music for digital pocket audio players such as MP3 players. This application requires a low cost, -not volatile and has a storage in which you can rewrite digital information that is usually reproduced in series. Using flat 200 nm wide cables, a NOT gate would occupy an area of 1 μp? 2. Therefore, a single lcm2 layer covered with data strings would provide 12 Mbytes of serial data storage, which is enough for 12 hours of CD-quality music. The "layer stacking will provide several hours of CD-quality audio at a very low cost - The temporary storage of digital photographs on digital cameras This function is currently achieved by FLASH electronic memory which is expensive and has a limited number of overwriting cycles - Non-volatile off-line storage for mobile phones, personal organizers, personal palm-top computers and S-ART (smart) cards.

Claims

NOVELTY OF THE INVENTION Having described the present invention, it is considered as a novelty and, therefore, the content of the following is claimed as a priority: CLAIMS

1. - A data storage device for storing digital information in a readable form comprises one or more memory elements, each memory element comprising a flat magnetic conduit having the ability to sustain and propagate a magnetic domain wall formed in a channel of continuous propagation, wherein each continuous channel is provided by ib minus with an inversion node in which the magnetization direction of a domain wall that propagates along the conduit is modified under the action of a convenient applied field, each inversion node comprises a portion wherein a change, of direction away from the initial path and a change of direction back to the initial path are provided in the conduit so that a direct propagation path through the portion is not possible of deviation. |

2. The data storage device according to claim 1, characterized in that each continuous channel is provided with at least one inversion node in which the magnetization direction of a domain wall propagating along of the conduit under the action of a suitable applied field is substantially inverted.

3. -. The data storage device according to claim 1 or 2, characterized in that each continuous channel is provided with a large plurality of inversion nodes.

4. - The data storage device according to any of the preceding claims, characterized in that a conduit is formed in a closed loop to comprise a continuous propagation channel.

5. - The data storage device, according to any of the preceding claims, characterized in that a conduit does not form a complete closed loop but rather a chain of inversion nodes, and means are provided for transferring data between the two ends of the same so that the data can continue to circulate around a seemingly closed loop, the means comprises a writing facility for damage at one end of the chain and a data reading facility at the other end of the chain, and circuitry additional to feed the data back electronically from the exit of the chain to the entrance of the chain.

6. - The data storage device according to any of the preceding claims, characterized in that the deviations comprise deviations of 90 ° from the initial path of the conduit.

7. - The data storage device according to any of the preceding claims, characterized in that the deviations of the initial path occur gradually over a distance along the channel of the conduit.

8. The data storage device according to any of the preceding claims, characterized in that the inversion node comprises a cycloidal portion within the structure of the conduit loop or a topological equivalent of said structure. 9.- The data storage device of. according to the rei indication 8, which also comprises a plurality of said cycloidal portions provided in each loop. 10. - The data storage device according to claim 9, further comprising a number of magnetic conduits formed in closed loops, each comprising a plurality of cycloids that. they serve to effect abrupt reversal inversions in a magnetization direction of a domain wall passing through them. 11. - The data storage device according to one of claims 8 to 10, characterized in that each cycloid has a rotating radius that is in the range of three to ten times the width of the conduit. 12. The data storage device according to any of the preceding claims, characterized in that the magnetic conduit comprises a particular generally flat magnetic cable on a suitable substrate. 13. The data storage device according to claim 12, characterized in that the magnetic cable comprises a magnetic nanowire with a thickness between 2 nm and 25 nm and a width between 50 nm and 1 μp?