Hydrothermal construction of VS₂/ZnFe₂O₄ composites with composition-regulated electromagnetic wave absorption

VS₂/ZnFe₂O₄ composites with ZnFe₂O₄ addition of 0-15% were prepared by a hydrothermal route to examine composition-dependent regulation of their electromagnetic parameters. For specimens containing 30 wt% absorber in paraffin, Z2, with a ZnFe₂O₄ addition of 5%, showed the strongest calculated absorption, yielding a minimum reflection loss of -45.1 dB at 7.85 GHz and an effective absorption bandwidth of 3.5 GHz (6.9-10.4 GHz) at 2.75 mm. Z2 exhibited the largest dielectric loss and a broader impedance-matched region than the other compositions, whereas the permeability of all samples remained close to unity. Room-temperature M-H curves of Z2-Z4 were weak, quasi-linear and unsaturated over ±10 kOe, with magnetization values of approximately 0.039-0.065 emu g^-1 at +10 kOe. Altogether, the electromagnetic and magnetic data support a predominant dielectric-dissipation and impedance-regulation role for the ZnFe₂O₄-derived component, while any magnetic contribution is secondary under the present measurement conditions. The non-monotonic composition dependence demonstrates that a moderate ZnFe₂O₄ addition is more effective than continuously increasing the nominal ferrite content.