The mechanically induced structural disorder in barium hexaferrite, BaFe₁₂O₁₉, and its impact on magnetism

Abstract

The response of the structure of the M-type barium hexaferrite (BaFe 12 O 19 ) to mechanical action through high-energy milling and its impact on the magnetic behaviour of the ferrite are investigated. Due to the ability of the 57 Fe Mössbauer spectroscopic technique to probe the environment of the Fe nuclei, a valuable insight on a local atomic scale into the mechanically induced changes in the hexagonal structure of the material is View Article OnlineView Journal | View Issue nm. The information on the mechanically induced short-range structural disorder in BaFe 12 O 19 is complemented by an investigation of its magnetic behaviour on a macroscopic scale. It is demonstrated that the milled ferrite nanoparticles exhibit a pure superparamagnetism at room temperature. As a consequence of the far-fromequilibrium structural disorder in the surface shell of the nanoparticles, the mechanically treated BaFe 12 O 19 exhibits a reduced magnetization and an enhanced coercivity.

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