Tuning the Structure, Magnetic, and High Frequency Properties of ScDoped Sr_0.5Ba_0.5Sc_xFe_12xO₁₉/NiFe₂O₄ Hard/Soft Nanocomposites

The magnetic nanocomposites (NCs) are technologically significant materials in the development of energy devices for a variety of applications such as electromagnetic interference (EMI) shielding and memory.[1,2] Individual hard and soft ferrites as magnetic particles are exceptional properties. M-type hexaferrites with the formula of MFe12O19, including BaFe12O19 and SrFe12O19 are hard ferrites that have large coercivity (Hc, high resistance to demagnetization), large saturation magnetization (Ms), high magnetocrystalline anisotropy, and high ferromagnetic resonance frequency.[3–5] The substitution of Fe3+ ions in hexaferrite can result in a variation in the magnetic properties depending on the dopant.[6–8] On the other hand, spinel ferrites with the formula AB2O4 are soft ferrites that have low coercivity, low saturation magnetization, and low anisotropy. Nickel ferrite (NiFe2O4) The Sr0.5Ba0.5ScxFe12–xO19(SrBaSc)/NiFe2O4(NiFe) hard–soft nanocomposites (NCs) are synthesized by in situ sol–gel route. Impact of Sc3+ doping on their structure, morphology, and magnetic properties are examined. X-ray diffraction confirms the coexistence of SrBaSc and NiFe phases without any impurity. Morphology of NCs reveals a cluster of hexagonal plate decorated by spherical grains. Magnetic characteristics of the NCs are examined by using a vibration sample magnetometer at room temperature and 10 K. The x = 0.000 sample shows some kinks in their M–H loops and the occurrence of two peaks in dM/dH(H). All the NCs with Sc3+ exhibit smooth shapes of M–H curves with single peak, revealing the complete and perfect exchange coupling behavior. The diverse magnetic parameters at both temperatures are determined. The values of saturation and remanent magnetizations are decreasing with the Sc content increase. The intensive electromagnetic absorption is observed in all the samples. Reflection loss (RL) of more than -18 dB is observed above 3 GHz. Strong coupling between Sc concentration and amplitude–frequency characteristics of the RL can be used for developing of the functional media for high-frequency devices and will open broad perspectives for practical application in radar-absorbing technology and electromagnetic compatibility.