Magnetic properties of (Fe, Fe-B)/γ-Fe2O3 core shell nanostructure

► Core/shell structure with (α-Fe, Fe-B) core and γ-Fe2O3 shell is synthesized. ► Diameter of the core is 20 nm and the shell is 7 nm thick. ► The role of the core and the shell in the magnetic properties is determined. ► The observed blocking temperature TB=30 K is associated with the γ-Fe2O3 shell. ► Size dependence is used to explain the observed absence of exchange bias.