Авторы: Yu Y., Tauxe L.

2008 г.

Phys.Earth Planet.Int.

     Direct calibration of magnetic hysteresis with grain size is of particular interest for sub-micron particles. In the present study, we numerically tested the effect of particle shape (grain morphology and aspect ratio) on magnetic hysteresis of stress-free Fe₃O₄. We found that the particle shape has a profound effect on hysteresis behavior. In particular, for particles with grain width > 120 nm, octahedra (and tetragonally terminated prisms) showed higher coercivity and squareness than cubes (and rectangular parallelepipeds) due to an inherent geometric advantage. Results from micromagnetic calculations and experimental observations are somewhat mismatching. It is likely that stress-free Fe₃O₄ used in hysteresis experiments were not entirely stress-free or the grain size of stress-free Fe₃O₄ was overestimated on using two-dimensional images of three-dimensional objects

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