Synthesis and Magnetic Properties of BaFe$_{12- {\rm x}}$ Al$_{\rm x}$ O$_{19}$ Nanopowders

The effect of Al contents on the magnetic properties of Ba hexaferrite powders has been investigated in order to increase the coercivity. In this study, a self-propagating combustion method has been developed to form Ba hexaferrite nanopowders. X-ray diffraction (XRD) and transmission electron microscopy (TEM) analysis showed that nanopowders with a size of 40-60 nm were successfully produced. With increasing Al contents, the coercivity of the nanopowders increased until the powders had a magnetoplumbite structure. We obtained a coercivity of 7559 Oe in BaFe
₁₀
Al
₂
O
₁₉
powders calcined at 850deg for 1 h.