Thomson-csf

Jean Nicolas

Antoinette Morell

Mieczyslaw Hildebrandt

Roland Sroussi

Jacques Claudon

Alain Lagrange

Dielectrics without any residual magnetization, produced by the technique of ceramics sintered at high temperatures, usable in devices operating at very high frequencies, such as X band. They are obtained by sintering at lower temperatures than for known dielectrics suitable for those applications and correspond to two possible general formulae:

Dielectric and non-magnetic ceramic for high frequency applications

A ferrimagnetic material imparts a very high efficiency and/or sensitivity to recording read-out and erase heads cooperating with magnetic layer devices. The starting point of the manufacturing process of this material is a solution of mineral salts or oxides of zinc, nickel and iron, and, using physicochemical processes employed in the ceramic industry, in particular sintering under pressure, spinelle structure polycrystalline ferrites are produced which satisfy the general formula: Ni.sub.1-x Zn.sub.x Fe.sub.2(1+e) O.sub.4 where x ranges between 0.5 and 0.7 and e ranges between -0.08 and +0.015.

Method of manufacturing ferrimagnetic material for recording, read out

A method of manufacturing a magnetic head, with a relatively large gap for reading, for instance, magnetic cards, and having a good resistance to mechanical wear, is provided. The head comprises two members with flat and parallel faces, made of a spinel ferrite having a high Curie temperature, encompassing a layer of non magnetic ferrite, 10 to 50 micrometers in thickness, deposited by silk-screen printing on one or both of the mutually opposite flat faces. The assembly is then bonded by sintering under pressure.

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Paris, France

Jean Nicolas