Highly Oriented SrM Tape Hexaferrite

This paper reports on preparation of a magnetically anisotropic polycrystalline hexaferrite, Sr Ca Fe O , whose orientation degree is as high as 100%. The preparation uses standard ceramic techniques, including wet pressing and flowing-oxygen sintering. In this process, Ca ions are substituted for Sr ions in SrFe O by adding minimum impurities (Bi O and MnCO ). Such a hexaferrite has a dielectric loss lower than at 9.5 GHz, which is important for microwave applications and possibly for millimeter-wave applications. The paper describes the variation of specific saturation magnetization and magnetic crystal anisotropy field ( ) with temperature ( ), and compares the magnetic properties of the sintered hexaferrite with those of the strontium hexaferrite SrFe O .