Magnetic model for a horse-spleen ferritin with a three-phase core structure

► We present a new model (Σ3L) of the initial magnetization of ferritin, considering its different phases. ► New model includes three Langevin-function terms, which represent three different magnetic moments provided by ferritin phases. ► Compared to previous models, our simple model fits the experimental data 12 times better in terms of the sum of least square. ► The magnetic independence of each component supports that ferritin and ferrihydrite are composed of different phases.