How do ferrite and powdered iron compare for use in an inductor core?
Ferrite cores generally have lower initial permeability
Ferrite cores generally have better temperature stability
Ferrite cores generally require fewer turns to produce a given inductance value✓Bonne réponse
Ferrite cores are easier to use with surface-mount technology
Explication
Inductance rises with the core’s ability to concentrate magnetic flux and with the square of the turns count, so a ferrite core — with a magnetic response typically in the hundreds or thousands against tens for an iron-powder composite — reaches a given inductance with far fewer turns. That also means ferrite has a stronger initial magnetic response, not lower, while the iron-powder composite is the more temperature-stable of the two.