| 摘要 |
1,257,857. Magnetic storage devices. WESTERN ELECTRIC CO. Inc. 27 Aug., 1969 [29 Aug., 1968], No. 42605/69. Heading H3B. In a magnetic device comprising a layer of magnetic material having associated therewith an overlay of magnetic material to define a single wall domain producing region and a domain propagation channel the arrangement is such that when an appropriate magnetic field rotating in the plane of the layer is applied a single wall domain is produced at the input of the channel and propagated therealong. In the arrangement of Fig. 1 the single wall domain producing region and propagation channel of sheet 11 are defined by a disc 15 and bar and T-shaped overlays 13, 14 of permalloy. When a rotating magnetic field H produced by orthogonal sets of coils B, B<SP>1</SP> is applied a permanent domain D provided in the layer 11 moves about the periphery of the disc as shown in Figs. 2-8, positive poles induced in the overlay by the magnetic field attracting the domain. The domain is stretched until as shown at Fig. 7 it is about to divide into two, then Fig. 8 the domain divides one following the bar and T and the other D<SP>1</SP> moving about the disc again. The rotating field also results in propagation of the domains along the channel to the output position coupled by conductors 19, 21, a pulse on conductor 19 resulting in a domain coupled thereto collapsing the domain and inducing a signal in conductor 21, the presence or absence of a domain indicating a "1" or "0". Since the field required for propagation is less than that required to divide the domain D the rotating magnetic field has its strength varied so that it is only increased when a domain is to be introduced and then only for the last quarter of the cycle. The overlays for a plurality of propagation channels may be provided on one side of the magnetic layer 11 and the respective input overlays each of different geometry e.g. rectangular, disc or cross-shaped on the other side, Fig. 9 (not shown). The amplitude of the rotating field thus determines the channel into which a domain is introduced. By providing a generalized pattern of overlays domains may be introduced and propagated in X and Y directions. Domains may be introduced into more than one channel from a given input overlay by increasing the amplitude of the rotating field during different quarter cycles, Figs. 10 to 13 (not shown). In a further arrangement three parallel bars of permalloy are used, Figs. 14, 15 (not shown) two of the bars being of low coercive force and the middle one of high coercive force. |
