Nanoparticle Size Distribution and Surface Effects on the Thermal Dependence of Magnetic Anisotropy

Standard approaches to investigate the anisotropy of nanoparticle assemblies are either by means zero-field-cooled–field-cooled DC magnetization curves or analyzing coercivity at low temperatures. However, these methodologies restricted average values an constant, without probing its temperature dependence symmetry. In this context, thermal arises as a more comprehensive approach assess anisotropic properties. Here, we experimentally for cobalt ferrite samples synthesized different methods, in large range diameters, resulting with internal structure, surface roughness, and size distribution. Our analysis consists accounting distribution relevant variables, allowing us access constant function temperature. The results indicate that plays important role low-field determined constants, pointing combination types/sources affecting coercivity. While cubic magnetocrystalline dominates nanoparticles higher diameter, influence contribution increases substantially smaller sizes. state is shown be key determining main source anisotropy.