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 (M_s) and the remnant (M_r) magnetizations values are maximum for pristine SrY_0.5Ce_0.5Fe₁₁O₁₉ (i.e. x=0.5) and SrY_0.3Ce_0.3Fe_11.4O₁₉ (i.e. x?=?0.3) due to both Y³⁺ and Ce³⁺ contents. The obtained squareness ratio (M_r/M_s) 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 (H_a) values are very large indicating the hard-ferromagnetic features of all elaborated nanoparticles samples. It is found that H_a 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 (H_c) value is diminished due to Y³⁺ and Ce³⁺ substitutions and its minimum corresponds to x?=?0.3. The blocking temperatures (T_B) are estimated from ZFC and FC magnetizations experiments. It is observed that T_B shifts to higher temperatures with rising Y³⁺ and Ce³⁺ contents. This is ascribed to the reduction of particles size with Y and Ce substitutions.