Accession Number : AD0287613

Title :   FINE-GRAINED FERRITES. II. NI1-XZNXFE204

Corporate Author : ARMY ELECTRONICS LABS FORT MONMOUTH N J

Personal Author(s) : MALINOFSKY,W.W. ; BABBITT,R.W. ; SANDS,G.C.

Report Date : MAR 1962

Pagination or Media Count : 1

Abstract : A series of fine-grained single-phase fertes was prepared according to the formula Ni1-xZnxFe2O4, where x took the vaues 0.10, 0.33, 0.50, and 0.67. A process combining the socalled flame-spraying and hot-pressing techniques was sed to obtain grain sizes of approximately 0.1 micron in the densified bodies. Measurements were made to 3.8 Gc on a ferrite annealed through the critical size for multidomains, confirming the previosly reported theory that magnetic poles on the domain walls are the source of the microwave peak at about 2 Gc. In addition, the temperatre dependence of initial permeability was studied. The temperature coefficient was found to increase with grain size. Microwave properties were also studied. Because zero-fied (Hdc = O) measurements showed that fine grains (i.e., below the ritical size for multidomains) eliminated the so-called microwave loss pek in the rf dispersion, a decrease in the low-field loss follows. Microwave measurements of the main resonance loss susceptibility vs. rf power were made at X band using a cavity technique. Although noral critical fields were generally found, one ample with x = 0.67 and deta H = 655 oersteds showed an anomalous rise at high powers, significantly expanding its power-handling capability. (Author)A-287 6139N3 +++Preparation of a series of fine-grained ferrites with the formula NI!-XZnxFe2O4 where x is 0.10 to 0.67; microwave properties and temperature dependence of permeability.

Descriptors :   *FERRITES, *FERROMAGNETIC MATERIALS, CRYSTALS, HIGH FREQUENCY, IRON COMPOUNDS, MAGNETIC PROPERTIES, MICROWAVES, NICKEL COMPOUNDS, OXIDES, RADIOFREQUENCY, STABILITY, TEMPERATURE, ZINC COMPOUNDS

Distribution Statement : APPROVED FOR PUBLIC RELEASE