Structural and magnetic properties of Ni-substituted Y-type Ba_0.5Sr_1.5Zn_2−xNi _xFe₁₂O₂₂ (x = 0, 0.5, 1.0, and 1.5) hexaferrite

Y-type hexaferrite falls under the spin-induced multiferroic materials category showing significant magnetoelectric coupling. The operating temperatures are reported to be tuned through proper substitution. Here in this study, Y-type hexaferrite Ba_0.5Sr_1.5Zn_2−xNi_xFe₁₂O₂₂ (x = 0, 0.5, 1.0, and 1.5) is synthesized by a solid-state reaction technique, and the effect of substitution of Zn²⁺ ions with Ni²⁺ ions on the magnetic spin transition temperature is studied. X-ray diffraction analysis confirms the formation of the Y-type hexaferrite phase. The lattice contracts with an increase in the Ni-ion content. Hexagonal-shaped grains with particle size in the range of 2–8 μm are analyzed using scanning electron microscopy. Temperature-induced magnetic transitions are visible in all the compositions. The M–T measurements show that the ferrimagnetic to paramagnetic transition temperature can be tuned from 510 to 750 K via Ni²⁺ ion substitution. Furthermore, magnetic field-induced spin phases are evident through the multistage hysteresis from the M–H loops of the sample for x = 0.5 and 1.5.