Magnetic permeability stability of composite material with nominal composition Ni0.6Fe2.4O4

A composite material with a nominal composition of Ni _0.6Fe _2.4O ₄ was prepared by the solid-phase reaction method. X-ray diffraction analysis shows that the product is composed of α-Fe ₂O ₃ and a solid solution of Fe ₃O ₄ and NiFe ₂O ₄. Although α-Fe ₂O ₃ non-magnetic phase reduces the saturation magnetization, it greatly improves the temperature and frequency stability of magnetic permeability. Based on the measurement results of the amplitude permeability in the range of −60 °C to 100 °C, the temperature coefficient α _μ and specific temperature coefficient β were calculated. α _μ and β of the composite material are 7.15 × 10 - 5 / ° C and 8.6 × 10 - 6 / ° C , respectively, which are much smaller than α _μ (1.26 × 10 - 3 / ° C ) and β (9.5 × 10 - 5 / ° C ) of NiFe ₂O ₄. At the same time, the magnetic spectrum curves show that the real part of the complex permeability μ` basically remains unchanged within the measurement frequency range ( f < 10 ⁶ Hz). This improvement in temperature and frequency stability is attributed to the effect of the α-Fe ₂O ₃ phase.