Structural and magnetic properties of praseodymium substituted strontium-based spinel ferrites

Spinel ferrites with composition SrPrxFe2−xO4 (x = 0.0, 0.025, 0.05, 0.075, 0.10) were synthesized successfully by sol–gel technique. Structural properties of all the samples were measured from X-ray diffraction (XRD) and scanning electron microscopy. XRD analysis indicated the spinel phase at the low concentration of praseodymium ions (x ≤ 0.05) while at high concentration, few traces of secondary phase (PrFeO3) were also observed along spinel phase. The distribution of all the grains showed the inhomogeneous behavior. Temperature dependence normalized AC susceptibility and Curie temperature study of spinel ferrites reveals that SrFe2O4 exhibits multidomain (MD) structure with high Curie temperature while on the substitution of praseodymium, MD to SD transitions occurs. Magnetic properties of all the spinel ferrites showed narrow M–H loops. With the substitution of praseodymium ions, coercivity (Hc) of strontium-based samples presented the increasing trend, while saturation magnetization (Ms) and remanence (Mr) both decreased. The above-mentioned parameters suggested that the synthesized samples might be suited for the application of high-density magnetic recording.