Outstanding heat loss via nano-octahedra above 20 nm in size: from wustite-rich nanoparticles to magnetite single-crystals

at 40 mT and 300 kHz). Most importantly, the magnetic response and the hyperthermia performance of properly coated F-MNPs are kept basically unaltered in media with very different viscosities and ionic strength. Finally, using a physical model based on single magnetic domain approaches, we derive a novel connection between the octahedral shape and the high hyperthermia performance.