Methods of preparing ferrite powders for use in microwave elements such as isolators, circulators, phase shifters and transmission line elements. In one method separate precipitations of metal dicarboxylate salts such as oxalates or malonates are mixed with a ferrous dicarboxylate. This is followed by mixing and calcining of the precipitated dicarboxylates to form the ferrite powder. In another method metal acetates in a solution of concentrated acetic acidare mixed with iron powder to form a solution which is mixed with malonic acid. The resulting mixed metal malonates are processed into a powder which is calcined to obtain the ferrite. To form a lithium ferrite, lithium carbonate is added to prepared powders prior to the calcining step.
RELATED APPLICATION
This application is related to application Ser. No. 08/685,885, entitled Process for Fabricating a Microwave Power Device filed Jul. 25, 1996, now U.S. Pat. No. 5,772,820 which is a continuation-in-part of application Ser. No. 08/511,927, entitled Planar Phase Shifters Using Low Coercive Force and Fast Switching, Multilayerable Ferrite, filed Aug. 7, 1995, now U.S. Pat. No. 5,744,025. These applications are herein incorporated by reference.
A substrate and a target are disposed within a vacuum chamber, and an oxygen partial pressure within the vacuum chamber is set to 1.times.10.sup.-5 or less. Under this condition, a spinel ferrite thin film selected from the group consisting of compounds represented by the formula AE.sub.1+t Fe.sub.2-2t TM.sub.t O.sub.4, where AE represents an alkaline earth metal or an alkali metal, TM represents a transition metal and t falls within a range of between 0.2 and 0.6, and compounds represented by the formula Zn.sub.1-x Co.sub.x Fe.sub.2 O.sub.4, where x falls within a range of between 0.2 and 0.7, is deposited on the substrate by laser beam deposition. The particular method makes it possible to provide a spinel ferrite thin film realizing a spin glass state under temperatures around or higher than room temperature and capable of controlling the spin state by light.
Magnetoelectric multilayer composites comprising alternate layers of a bimetal ferrite wherein one of the metals is zinc and a piezoelectric material for facilitating conversion of an electric field into a magnetic field or vice versa. The preferred composites include cobalt, nickel, or lithium zinc ferrite and PZT films which are arranged in a bilayer or in alternating layers, laminated, and sintered at high temperature. The composites are useful in sensors for detection of magnetic fields; sensors for measuring rotation speed, linear speed, or acceleration; read-heads in storage devices by converting bits in magnetic storage devices to electrical signals; magnetoelectric media for storing information; and high frequency devices for electric field control of magnetic devices or magnetic field control of electric devices.
