Metastability threshold sizes in single‐domain magnetite particles
Valeriy P. Shcherbakov, B.E. Lamash · Geophysical Research Letters · 1988
A micromagnetic model was developed to calculate the maximum grain size for which an ideal parallelepiped‐shaped particle can have a metastable single‐domain (SD) structure. For mathematical tractability, the micromagnetic equations were described only by one‐dimensional deviations from a uniform SD state. It was found that for cubic‐shaped magnetite particles, the metastability threshold, acr was approximately 0.14 micrometers, well above the equilibrium threshold size for the single‐domain to two‐domain transition. The metastability threshold size also increased rapidly with particle elongation and for a length:width ratio greater then 2.6, magnetite grains of all sizes could theoretically support a metastable single‐domain state.