Establishment of Preparation Process of Hexagonal U-type Ferrites Ba₄Me₂Fe₃₆O₆₀ (Me=Co, Ni, Mg) and Their Magnetic Properties

Abstract

We have established the preparation process of hexagonal U-type ferrites Ba₄Me₂Fe₃₆O₆₀ (Me=Co, Ni, Mg) and investigated their crystal structure and magnetic properties. The U-type ferrite single phase was not fabricated by using a conventional ceramic synthesis process which comprises two-steps: calcination and sintering. We have found that the U-type ferrites single phase can be obtained by a one-step sintering method that skips the calcination process. The single phase of the U-type ferrite was formed at a very narrow temperature at about 1250°C. The values of saturation magnetization and the Curie temperature of Co₂U ferrite were higher than those of Co₂Z ferrite. Initial permeability of Co₂U ferrite has a higher value than those of Ni₂U and Mg₂U ferrites. The U-type ferrite has a great potential for high frequency magnetic materials.