Effects of Sr-substitution on the structural and magnetic behavior of Ba-based Y-type hexagonal ferrites

• Sr-substituted Y-type hexaferrites synthesized by sol–gel method have been investigated.
• Platelet grains with well defined hexagonal shape are suitable for microwave absorbers.
• Saturation magnetization values were calculated by the law of approach to saturation.
• Coercivity of a few hundred oersteds found for all samples is suitable for EM materials.

Sr-substituted samples of Y-type hexagonal ferrites with chemical formula Ba2−xSrxNi2Fe12O22 (x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0) were synthesized using the sol–gel autocombustion method and were sintered at 1150 °C for 3 h. The samples were investigated by differential thermal and thermogravimetry analysis, X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy and vibrating sample magnetometry. X-ray diffraction analysis reveals that single phase samples can be achieved by substituting Sr2+ ions at Ba2+ sites in Y-type hexagonal ferrites. X-ray density and bulk density were observed to decrease whereas porosity increased with increasing Sr-concentration. All the samples show well defined hexagonal shape which is favorable for microwave absorbing purposes. The saturation magnetization values were calculated from M–H loops by the law of approach to saturation. The loops show low values of coercivity of a few hundred oersteds which is one of the necessary conditions for electromagnetic (EM) materials and is suitable for security, switching, sensing and high frequency applications.

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