Accession Number : AD0464540


Title :   FINE GRAIN DENSE FERRITES


Descriptive Note : Quarterly rept. no. 3, 1 Jan-31 Mar 1965,


Corporate Author : RAYTHEON CO WALTHAM MA


Personal Author(s) : Paladino, A E ; Waugh, J S ; Green, J J ; Owen, J Q ; Booth, A E


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/464540.pdf


Report Date : 31 Mar 1965


Pagination or Media Count : 44


Abstract : A number of new compositions were prepared in the vicinity of the compensation point in the series Ni sub 1-xCoxFe2O4. No systematic variation in the threshold field or magnetic loss was observed with cobalt concentration, although threshold fields were as high as 108 Oe at KU-band. Lowering the hot- pressing temperature from 1200 to 1150 C had no consistent effect on microwave properties. Annealing studies at 1200 and 1250 C indicate that the threshold field decreases significantly with time for nickel and nickelmanganese ferrites, whereas it remains high in nickel-cobalt ferrites. The magnetic loss in general decreases with increasing time; it decreases most for nickel and nickel- manganese ferrites, and least for nickel-cobalt ferrites. A satisfactory device geometry has been established for a differential phase-shift circulator. Low power phase shift and insertion loss measurements have been made on a conventional and finegrain, nickel-cobalt ferrite. Although the insertion loss of the fine-grain ferrite is about double that of the conventional material due to a magnetic loss of approximately twice that of the conventional material, a circulator with less than or equal to 0.5 dB loss can be constructed.


Descriptors :   *FERRITES , MAGNETIC PROPERTIES , MICROWAVE EQUIPMENT , NICKEL COMPOUNDS , GRAIN STRUCTURES(METALLURGY) , COBALT COMPOUNDS , TEMPERATURE , HEAT TREATMENT


Subject Categories : Inorganic Chemistry


Distribution Statement : APPROVED FOR PUBLIC RELEASE