Abstract: A Bloch line magnetic memory has a magnetic film of thickness h located on a substrate and includes Bloch lines of width .LAMBDA.o. The magnetic film satisfies the condition (1) h/.LAMBDA.o<14 with .LAMBDA.o=.sqroot.A/2.pi.Ms.sup.2, in which A represents the magnetic exchange constant and 4.pi.Ms represents the saturation magnetization of the film.

Abstract: Method for preparing a magneto optic memory comprising on a support (22), such as one made of glass, metal or a plastic material, a planar sensitive film (21) of magneto optic material for receiving at each point the recording of one of the two binary digits 0 and 1 in the form of small domains juxtaposed and magnetized perpendicular to the plane of the film in one of the two possible directions with respect to the latter, the sensitive film (21) being deposited by a cathodic or other evporation process of a magentic oxide selected from the group including spinel ferrites, hexaferrites and ferrimagnetic garnets, the preceding deposition being followed by a crystallization of the amorphous regions of said film with the aid of an annealing, wherein at least one reflective film (28) and/or one film constituting a thermal screen is inserted between the support (22) and the sensitive film (21) and wherein the annealing is a fast annealing, namely of a few seconds at a temperature of between 600.degree. C. and 650.

Abstract: Process for regulating to desired values the size of the bubbles of magnetic bubble elements during the manufacture of such elements by liquid phase deposition into a non-magnetic substrate of a ferrimagnetic garnet film of formula:(T.sub.a.sup.1 T.sub.b.sup.2 T.sub.c.sup.3 Ca.sub.d) (Fe.sub.e Ge.sub.g) O.sub.12in which T.sup.1, T.sup.2 and T.sup.3, which differ from one another, represent an element in the series of rare earths, including yttrium, a,b,c and d are numbers such that their sum is substantially equal to 3 and e and f are numbers such that their sum is substantially equal to 5, wherein such elements are produced by using epitaxy baths comprising calcium oxide or carbonate and predetermined quantities of ferric oxide, oxides of elements T.sup.1, T.sup.2 and T.sup.

Abstract: The wave guide is constituted by a film layer C.sub.1 of magnetizable material having a constant refractive index n.sub.1 and placed between two media having refractive indices of lower value than the index n.sub.1. The layer C.sub.1 has two flat parallel surfaces which separate the layer C.sub.1 from the two media which have lower refractive indices and is constituted by a plurality of adjacent regions forming parallel layers, the gyrotropy of at least two of these regions being different.