GB1142035A - Magnetic thin film device - Google Patents

Abstract

1,142,035. Magnetic storage apparatus. HUGHES AIRCRAFT CO. 6 Sept., 1966 [6 Oct., 1965], No. 39745/66. Heading H3B. [Also in Division H1] A uniaxial or isotropic magnetic thin film storage element has magnetically coupled thereto a plurality of electrical conductors spaced apart in side-by-side arrangement and connected in series, the inner ones passing over the element and the outer ones being outside the bounds of the element. The conductors are arranged so that the current through the inner conductors is in the same direction and produces a cumulative magnetic field whereas the current through the outer conductors is in the opposite direction to the first direction so that the associated magnetic fields reduce the magnetic field strength in the fringe areas of the cumulative magnetic field. In the arrangement of Figs. 3, 4, a plurality of thin film elements 12 are deposited on a glass substrate 54 which is sandwiched between two congruent sets of conductors 16 to 22 and 28 to 36 produced by printed circuit techniques. A current is applied to terminal 40 on conductor 14 and flows in the direction shown by the solid arrows in the upper conductors until it reaches the end of conductor 24 when it is transferred by circuit connection 25 to the lower conductor 26 and travels in the directions shown by the dotted arrows in this conductor to output terminal 42. Thus the current in the conductors situated over the film element 12 produce a cumulative magnetic field whereas the current flowing through the conductors 18, 22, 30 and 34 not situated over the element 12 produce a field opposite to the cumulative field and tend to cancel out this field in the fringe area and hence isolate the element, Fig. 5 (not shown). When a plurality of units are employed to form a memory conductors 14, 26 extend parallel to the axis of anisotropy and function as a word winding. A common bit/sense line is positioned perpendicular to the word line. Instead of single elements, sheets of thin films may be employed with the windings defining discrete areas of the sheets. Read-out is non-destructive.