Effect of 200 MeV Ag¹⁶⁺ swift heavy ion irradiation on structural and magnetic properties of M-type barium hexaferrite

M-type barium hexagonal ferrite (BaFe₁₂O₁₉) has been synthesized by sol-gel auto combustion method. The synthesized material was irradiated with 200 MeV Ag¹⁶⁺ ions using the 15UD Pelletron tandem accelerator and the changes in structural and surface morphology of material were investigated. The pristine (as-synthesised) and irradiated samples were characterized using different experimental techniques like x-ray diffraction (XRD), Fourier-transform infrared spectroscopy, transmission electron microscope (TEM) and vibrating sample magnetometer (VSM). The strong absorption peak between 580 and 440 cm⁻¹ in the infrared spectrum and XRD confirmed the formation of ferrite structure for both irradiated and pristine samples. XRD peaks for the irradiated barium hexagonal ferrite were slightly broadened when compared pristine ferrite samples. The crystallite size of the irradiated barium hexagonal ferrite was higher than that of pristine barium hexagonal ferrite and is consistent with TEM images. Both saturation magnetization and coercivity were decreased with irradiation. (paper)