New Synthetic Route of Z-Type (Ba$_{3}$Co$_{2}$Fe$_{24}$O$_{41}$) Hexaferrite Particles

Abstract

Z-type barium hexaferrite particles were synthesized by a one-step mixing-calcination process (MCP) and its magnetic properties were characterized and compared to the sol-gel (SGP) and the conventional ceramic (CCP) processed Z-type Ba hexaferrite with two-step calcination. We have used 71.2% pure M-type (BaFe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">12</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">19</sub> ) and 83.8% pure Y-type (Ba <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Co <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">12</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">22</sub> ) precursors to synthesize Z-type by the MCP. As a result, 77.8% pure Co <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Z hexaferrite particles were obtained. The purities of Co <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Z hexaferrite particles processed by SGP and CCP were 75.1% and 70.7%, respectively. It was found that purity of Z-phase was controllable by purity of M- and Y-type precursor particles in the MCP. Loss tan delta of sintered MCP Co <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Z decreased from 0.17 at 50 MHz to 0.068 at 300 MHz, while loss tan delta of sintered SGP and CCP Co <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Z were 0.12 and 0.09 at 300 MHz. It is found that this loss tan delta is controllable by the purity of Z-phase and sintering process. These results imply that our new process is potentially applicable to synthesis of any other hexaferrites and also cost-effective.