Abstract: A mixture of oxides or salts of barium, titanium and tin (principal materials) are initially ground with two different classes of dopants. The first class consists of oxides or salts of rare earths or of elements such as antimony. The second class consists of oxides or salts of elements such as manganese or copper. After calcining and sintering, cooling of the ceramic body is obtained by adjusting to a very low rate (negative gradient of 10 to 30.degree. C. per hour) in a pure oxygen atmosphere.The material is primarily suited for use in capacitors having one or a number of layers which may be separated by electrodes inserted prior to sintering. The material has high apparent permittivity and can be employed at much higher voltages than in barrier-layer capacitors.

Abstract: 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.