Magnetic and Absorption Characteristics of Mn and Ti Substituted Barium Hexaferrite for Microwave Absorber

Abstract

This paper reports our recent investigation on Mn+2 and Ti+2 and Substituted Barium Hexaferrites. Mterials of nominal compositions BaFe12-2x(MnTi)2O19 (x = 0.0; 1.5 and 2.5) were prepared through a wo-stage process by mechanical alloying and successive sintering. The first stage was the preparation of (Fe,Mn,Ti)2O3 obtained from partial substitution of Mn+2 and Ti+4 ions in a single phase Fe2O3 and (Fe,Mn,Ti)2O3 components were mechanically alloyed. Asuccessive solid state reaction at different sintering temperatures has lead to the formation of Mn and Ti substituted barium hexaferrite. Phase identification by XRD confirmed the single phase material. Microstructure by TEM showed grains are extremely fine about 30 nm in size. The electrons diffraction rings of the area shown uniform intensity around Debye rings indicating that grains are randomly oriented. Evaluation on the magnetic characteristic for the materials indicated tha coercivity decreased progressively as the number of Mn+2 and Ti+2 ions increased although this was also followed by a less significant decrease in the total magnetization. As to the microwave absorber, reflection and transmission coefficients as well as reflection loss in the frequency range 1 6 GHz were derived. In this paper, Absorption performances of nanocrystalline Mn and Ti substituted barium hexaferrite materials are also reported.