Nanocrystalline M-type Hexaferrite Powders: Preparation, Geometric and Magnetic Properties
Co-Ti-Sn-Ge substituted M-type bariumhexaferrite powders with mean grain sizes between about 10 nm and about 1 μm and a narrow size distribution were prepared reproducibly by means of a modified glass crystallization method. At annealing temperatures between 560 and 580 °C of the amorphous flakes nanocrystalline particles grow. They behave superparamagnetically at room temperature and change into stable magnetic single domains at lower temperatures. The magnetic volume of the powders is considerably less than the geometric one. However, the effective anisotropy fields are larger by a factor of two to three.
P. Görnert and H. P. Pfeiffer and E. Sinn and R. N. Müller and W. Schüppel and M. A. Rösler and X. Batlle and M. García del Muro and J. Tejada and S. Gali, "Nanocrystalline M-type Hexaferrite Powders: Preparation, Geometric and Magnetic Properties," IEEE Transactions on Magnetics, Institute of Electrical and Electronics Engineers (IEEE), Jan 1994.
The definitive version is available at http://dx.doi.org/10.1109/20.312385
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