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    A thin magnetic film store and a method of operating such a store
    11.
    发明专利
    A thin magnetic film store and a method of operating such a store 未知

    公开(公告)号：GB1089817A

    公开(公告)日：1967-11-08

    申请号：GB4480966

    申请日：1966-10-07

    Applicant: IBM

    Inventor： MIDDELHOEK SIMON

    IPC: G11C11/14 ,  G11C11/15 ,  G11C17/02

    Abstract: 1,089,817. Magnetic storage devices. INTERNATIONAL BUSINESS MACHINES CORPORATION. Oct. 7, 1966 [Nov. 2, 1965], No. 44809/66. Heading H1T. [Also in Division H3] A data storage device consists of two thin magnetic films having parallel easy axes and different critical switching fields, and means for applying a biasing magnetic field to rotate the magnetization of one film towards the hard axis without substantially rotating the magnetization of the other film. In Fig. 1 the storage film 12 has a critical field H KS of 5À0 oersted and the switching film 14 has a critical field H KL of 0À5 oersted. The films are evaporated on to a non-magnetic substrate and are separated by a layer 13 of SiO 2 . The biasing field, which may be supplied by a conductor parallel to the easy axis, by a coil or by a permanent magnet, may be applied continuously or only prior to and during a read operation. For read-out if the biasing field is equal to H KL , an equal and opposite field of 0À5 oersted is applied by passing current through a word line, allowing the magnetization of the switching film to fall back to the easy axis in a direction determined by the direction of magnetization of the storage film. The polarity of the output voltage induced in a sense line parallel to the hard axis indicates the data stored. For writing, a word field equal to or greater than the sum of H KS and the biasing field is applied simultaneously with a bit field parallel to the easy axis, so that the magnetization of the storage film is switched. The bit field preferably terminates, and may start, later than the word field. A matrix is described (Fig. 5, not shown) having either separate or common bitsense lines.

    14.
    发明专利
    未知

    公开(公告)号：DE1270110B

    公开(公告)日：1968-06-12

    申请号：DE1270110

    申请日：1964-12-31

    Applicant: IBM

    Inventor： KEEFE GEORGE EDWIN ,  MIDDELHOEK SIMON

    IPC: G11C7/02 ,  G11C11/14 ,  G11B5/78

    Abstract: 1,069,529. Magnetic storage devices. INTERNATIONAL BUSINESS MACHINES CORPORATION. Dec. 21, 1964 [Jan. 7, 1964], No. 51757/64. Heading H1T. [Also in Division H3] Information is written into an anisotropic magnetic film structure (which may be a single film or multiple single domain films side-by-side with or without air gap) by applying a hard direction field or fields and an over-lapping easy direction field to the film structure, the hard direction field or fields being varied or terminated in such a way that a portion (domain) only of the film structure becomes magnetized in a given direction, an adjacent portion or portions being magnetized in the opposite direction. Fig. 6 shows a matrix in which, e.g., the single magnetic film 10.7 is subjected to hard direction fields by a pulse in line 20.1 and an overlapping longer lasting pulse in line 22.1, a coincident easy direction bit pulse in line 16.1 terminating after the termination of the hard direction pulse in line 20.1 so that the magnetic vector in the part of the film under line 20.1 is swung into a direction along the easy axis determined by the bit pulse in 16.1. The hard direction pulse in line 22.1 terminates after cessation of the bit pulse and the magnetic vector in the portion of the film under line 22.1 is said to assume a direction along the easy axis opposite to that of the magnetic vector in the part of the film under 20.1 (Fig. 2, not shown). Magnetic films which demagnetize, after application of hard direction field, into four or more domains may be used, the word conductors over alternate domains being connected serially. Non-destructive readout is obtained by passing an interrogating pulse through one of the word conductors 20.1 or 22.1. In another arrangement (Figs. 7 and 8, not shown) a single word conductor (18a) passing over the centre part of the part of the film applies a large hard direction field which saturates the whole film in the hard direction. This field is reduced while an easy direction field is applied by a bit conductor (16) so that in the areas of the film on each side of conductor (18a) the magnetization vectors turn towards a first easy axis direction determined by the direction of the bit field. With further reduction and removal of the hard direction field the magnetization vector in the part of the film below conductor (18a) is said to assume a direction along the easy axis opposite to the first direction. The word line may be slotted.

    15.
    发明专利
    未知

    公开(公告)号：DE1258893B

    公开(公告)日：1968-01-18

    申请号：DEJ0020454

    申请日：1961-08-25

    Applicant: IBM

    Inventor： MIDDELHOEK SIMON

    IPC: G11C19/08

    Abstract: 975,575. Circuits employing bi-stable magnetic elements. INTERNATIONAL BUSINESS MACHINES CORPORATION. Aug. 31, 1961 [Aug. 31, 1960], No. 31377/61. Heading H3B. In a binary information transfer device which comprises a series of magnetic film elements having aligned easy axes of magnetization, and in which propagation of information is determined by the stray switching field of each element in association with selective conductor energization, the stray switching field is arranged to predominate at that end of each element which lies in the direction of propagation so that information transfer can take place only in one direction. The arrangement utilizes either wedge-shaped film elements, or shaped conductors which concentrate the switching field towards one end of elements of uniform thickness. The shaped conductors may either be parallel to the film elements and have a varying cross section, or their spacing from the elements may vary. The elements may also have non-uniform density. Two-clock systems. As shown in Fig. 1, separate wedge-shaped film elements 13-17 are deposited on a substrate 11 with their easy axes aligned in the direction 12. Two circuits A and B are provided which when energized by respective half-waves of alternating current switch the associated element groups 13, 15, 17 or 14, 16 to the hard direction. The halfwave clock pulses act alternately, and when a switched element relaxes from the hard to the easy direction of magnetization it takes up the magnetic state of the adjacent element having the larger adjacent edge dimension. In a modification, Fig. 5, two strip conductors provide the circuits A and B, the conductors being notched alternately so that the conductor portions effectively associated with the wedge film elements have different current densities. Thus the current density of conductor A is high for film element 57 and switches that element to the hard direction, and is low for element 58. The converse applies to conductor B which switches elements 56 and 58, for example. An alternative arrangement is shown in Fig. 6, in which the conductors A and B have alternate portions such as 65A, 64B adjacent the films which are linked together by non-effective webs 66A, 65B. Elements 71- 77 of uniform thickness are used in the Fig. 7 arrangement in which the conductors A and B are shaped so that their spacing over the length of each film element decreases. This has the effect of concentrating the field at one end of an element when switching to the hard direction of magnetization. Consequently, when the clock pulse in a conductor A or B decreases; each associated film element switches back to the easy direction along its length in the direction of information transfer, and therefore progressively acquires the magnetization of the preceding element. The same effect is obtained by the use of flat conductors A and B with tapered regions each corresponding to an element, Fig. 8. Logical circuits. A series of film elements may be used for logical operations. In Fig. 9, a reversal of 180 degrees causes a reversal of each magnetization vector and hence inversion of the information transferred from the upper to the lower limb. Reversal of direction without inversion is obtained in Fig. 10 in which a junction film element 99 is used. A junction element 107 is also used in Fig. 11 which is biased in the easy direction of magnetization by energizing a coil 108. With the bias flux directed to the left (as shown), the arrangement performs the logical operation AND on information advanced along the parallel branches 105, 106. With the bias flux directed to the right the logical operation is changed to OR. One-clock systems. In Fig. 13 wedge-shaped magnetic elements 113-118 are switched to the hard direction of magnetization by alternating current applied to a conductor 119. Alternate elements are partially biased in opposite hard directions by permanent magnets 120. During each half-cycle of the alternating switching current the hard direction bias fields of alternate elements such as 113, 115, 117 are neutralized, and the bias fields of the remaining elements are increased to cause complete hard direction switching. As the end of each halfcycle approaches, those elements which were completely switched to the hard direction take up the magnetic state, inclined to the easy direction as shown by vectors 122, of the elements immediately preceding. In a modification, Fig. 16, a notched conductor 140 may be used in association with film elements of uniform thickness. The permanent magnets may also be replaced by suitable conductors carrying constant currents. An alternative transfer device is shown in Fig. 17 in which wedge-shaped elements 151-155 are formed as a continuous magnetic film on a substrate 150. Otherwise a continuous magnetic film 161 of uniform thickness, Figs. 18 and 19, may be used in association with a non-parallel conductor 162. In both devices full-wave alternating current in a meander-shaped conductor 157 or 162 respectively applies a switching field which acts along the easy axis of the film. Due to the conductor arrangement the switching field acts in opposite directions in alternate elements. As the alternating switching field is not uniform along each element, it loses its effect progressively along each element in the direction of information transfer as the end of each half-cycle of current is approached. Each element is therefore able to progressively take up the magnetic state existing at the end of the preceding element by the process of domain wall movement. The pattern of information movement over a complete cycle of current is shown diagrammatically in Fig. 20, the arrows above the diagrams at times t 1 and t 3 representing the instantaneous directions of the switching field. Shifting register and ring counter. Construction as a shifting register is completed by the provision of input and output conductors adjacent the first and last elements respectively. As a ring counter the elements 181 are arranged in a ring as shown in Fig. 21, and for a oneclock system as in Figs. 17-19 have an associated switching conductor 180.

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