Hydrothermal Synthesis and Magnetic Properties of Hexagonal Sr3Co2Fe24O41 Particles

Sr
₃
Co
₂
Fe
₂₄
O
₄₁
(SrZ) ferrites were synthesized by a hydrothermal method. The effects of atomic ratio of Fe/Sr (R
_Sr
/Fe = x/8), hydrothermal reaction temperature (T
_H
) and reaction time (tH), and the sintering temperature (T
_s
) on the phase composition, microstructures, and magnetic properties of SrZ particles were investigated. In order to obtain a single Z-phase, x value in the initiative materials must be equal to 1.25. When x value is less than 1.25, α-Fe
₂
O
₃
, Sr
₃
Fe
₂
(OH)
₁₂
, and unknown phase appear in the precursor powders, ultimately leading to impurity phases in the sintered specimens. When x value is >1.5, synthesis of Z-phase is difficult, since superfluous α-Fe
₂
O
₃
phase exists with M-phase and spinel phase in the precursor powders. Hexagonal SrZ sheets of ~2 μm wide and dozens of nanometers thick were obtained under optimized conditions. The magnetic measurements reveal that the easy magnetization axis of hexagonal Z-phase sheets at room temperature lies in the c plane.