Impact of yttrium on the physical, electro-magnetic and dielectric properties of auto-combustion synthesized nanocrystalline strontium hexaferrite

Yttrium substituted strontium hexaferrite, SrAl4YxFe8-xO19 with x=0.0, 0.05, 0.10, 0.20, and 0.30, are prepared by the auto combustion method. The ferrites have been examined using XRD, SEM, FTIR, and VSM. The structural study confirms that the Y3+ ions reorganize themselves without troubling the parent lattice. In FTIR, the low wavenumber absorption bands confirm the hexagonal ferrites. Saturation (Ms) and remanence (Mr) magnetization is observed to decrease whereas, coercivity (Hc) and Curie temperature (Tc) is improved with Y3+ content. The variation in the dielectric constant () and dielectric loss factor (tan) is discussed in the frequency range of 20Hz-20MHz. The value of dielectric constant () and dielectric loss factor (tan) is decreased with Y3+ content. The optimized magnetic properties are obtained from x=0.20 compositions having Ms similar to 4.45emu/g, Mr similar to 1.91emu/g, Hc similar to 36kOe, (BH)(max)similar to 36.64MGOe and Tc similar to 614 degrees C. This material is very suitable for longitudinal recording media.