Selected properties of surface modified GaxFe3-xO4 with 0≤x≤1.5.

The influence of the surface modification on the magnetism of 4–14 nm sized core and core/shell gallium ferrites obtained by different preparation methods (Massart's and thermal decomposition from acetylacetonates) was studied. The physical properties of Ga_xFe_3-xO₄ were investigated in a wide range of Ga admixtures 0 ≤ x ≤ 1.5. Ga ions location at 8a or/and 16d positions of a spinel structure depends on the synthesis method and has a pronounced effect on the superparamagnetic properties of nanoparticles. Magnetization and Mössbauer experiments show the dominant superparamagnetic contribution for the nanoparticles with x > 0.8 with the blocking temperature TB significantly below 200 K. Surface-modified nanoferrites disclosed spontaneous magnetization that does not exceed 60 emu/g. [ABSTRACT FROM AUTHOR]