Highly Oriented SrM Tape Hexaferrite

摘要

This paper reports on preparation of a magnetically anisotropic polycrystalline hexaferrite, Sr{sub}0.95Ca{sub}0.05Fe{sub}12O{sub}19, 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{sup}(+2) ions are substituted for Sr{sup}(+2) ions in SrFe{sub}12O{sub}19 by adding minimum impurities (Bi{sub}2O{sub}3 and MnCO{sub}3). Such a hexaferrite has a dielectric loss lower than 2.3 × 10{sup}(-3) 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 σ{sub}s and magnetic crystal anisotropy field (H{sub}a) with temperature (T), and compares the magnetic properties of the sintered hexaferrite with those of the strontium hexaferrite SrFe{sub}12O{sub}19.