Fig. 5: Micromagnetic simulation results of reconstructed single giant magnetofossil particles.

A–J Selected modeled saturation isothermal remanent magnetization (SIRM) domain states with the lowest total magnetic energy of giant bullets, kinked giant bullets, needles, spearheads, and the sock-shaped crystal, with corresponding applied field directions provided in Supplementary Table S2 and S3. Arrows represent magnetic moment directions. Arrows are colored by the normalized magnetization in the direction perpendicular to the page. Vortex cores are colored orange. More simulated SIRM domain states are provided in Supplementary Fig. S8. K Stereographic projection of SIRM state directions in twenty external magnetic field directions. L The Néel diagram²⁴ shows coercivity (B_c) versus the ratio of saturation remanence to saturation magnetization (M_rs/M_s) of each reconstructed particle for needles (N), kinked giant bullets (KGB), giant bullets (GB), cone spearheads (CSH), no-stalk spearheads (NSSH), whole spearheads (WSH), and the sock-shaped crystal (sock). Colored circles, diamonds, downward-pointing triangles, and squares represent simulation results of different crystal elongation axes. Solid and hollow symbols denote SIRM directions onto the upper and lower hemispheres, respectively. Dark gray markers represent the hysteresis parameters of whole magnetotactic bacteria (MTB) cells (cuboctahedron and prism magnetite crystals; circles)^{31,32,33,34,35,36,37,38,39,40,41}, isolated magnetosomes (cuboctahedron and prism magnetite crystals; diamonds)^31,36,41, bullet-shaped magnetosomes (upward-pointing triangles)^25,41, conventional magnetofossils (squares)^{8,42,43,44,45}, extracellularly synthesized magnetite (crosses)^32,46,47, and chemically synthesized magnetite (pentagrams)^{48,49,50,51,52}. 95% confidence ellipses for the hysteresis data of typical magnetite categories are provided.