Structural and magnetic properties of Ce-Y substituted strontium nanohexaferrites

Strontium nanohexaferrites substituted with Ce-Y were synthesized via citrate sol-gel combustion. Crystallography phase and morphology were verified by X-ray diffraction, electron microscope and Raman spectroscopy. The magnetization hysteresis loop (M vs. H) revealed the ferromagnetic behavior of all prepared products. The estimated saturation (Ms) and the remnant (Mr) magnetizations values are maximum for pristine SrY0.5Ce0.5Fe11O19 (i.e. x=0.5) and SrY0.3Ce0.3Fe11.4O19 (i.e. x = 0.3) due to both Y3+ and Ce3+ contents. The obtained squareness ratio (Mr/Ms) values for substituted products are less than the value of 0.500 suggesting the uniaxial anisotropy for all substituted products. The magneto-crystalline anisotropy fields (Ha) values are very large indicating the hard-ferromagnetic features of all elaborated nanoparticles samples. It is found that Ha decreased with increasing both Y3+ and Ce3+ contents and is minimum for x = 0.5, which imply the weakening of magnetic properties. Therefore, the coercive field (Hc) value is diminished due to Y3+ and Ce3+ substitutions and its minimum corresponds to x = 0.3. The blocking temperatures (TB) are estimated from ZFC and FC magnetizations experiments. It is observed that TB shifts to higher temperatures with rising Y3+ and Ce3+ contents. This is ascribed to the reduction of particles size with Y and Ce substitutions.