Structural and Magnetic Properties of Ba1-xRexCo2ZnxFe16-xO27 W-type Hexaferrite prepared by Ball Milling Method

Abstract

Rare earth substituted W-type hexaferrites were prepared by mixing and ball milling starting powders with molar ratios consistent with the stoichiometry of Ba1-xRexCo2ZnxFe16-xO27 (Re is a rare-earth element; x = 0.1 and 0.2), pelletizing, and sintering 1300° C. X-ray diffraction patterns showed a pure W-type phase in all samples, except in the Nd-Zn (x = 0.1) substituted sample which revealed the presence of an impurity α-Fe2O3 nonmagnetic phase. The crystallization of the W-type phase in all samples was further confirmed by the characteristic Curie temperature ranging between 476° C and 484° C as revealed by the thermomagnetic measurements. Scanning electron microscopy imaging revealed the variations of the particle size and morphology, and porosity of the prepared samples. The magnetic measurements indicated that the RE–Zn substitution improved the saturation magnetization slightly relative to the un-substituted Co2W hexaferrite, and resulted in a decrease of the coercivity and magnetocrystalline anisotropy field. In addition, the peaks below 300° C in the thermomagnetic curves is an indication of the occurrence of spin reorientation transitions in the prepared hexaferrites.