Gamma-irradiation induced modifications in structural and magnetic properties of nanocrystalline Mn0.5Zn0.5 SmxFe2-xO4 ceramics

The changes in structure, infrared absorption and magnetic property of nanocrystalline Mn0.5Zn0.5SmxFe2-xO4 (x = 0.01, 0.03 and 0.05) ceramics were studied after different doses (0, 15 and 25 kGy) of γ-irradiation. The samples were prepared by solution combustion route. We observed that up to the highest studied dose (25 kGy) of γ-irradiation all the samples retain the cubic spinel (Fd-3m) structure as of the pristine samples, however, the lattice parameter decreases. Furthermore, we observed the metastability of Sm (and Mn) atoms at the octahedral sites. By Sm3+ doping the saturation magnetization of the pristine samples decreases, but the magnetic coercivity increases drastically, indicating enhancement of magnetic anisotropy. After γ-irradiation the magnetic anisotropy vanishes completely and the sample behaves super-paramagnetically with a small variation in saturation magnetization. Our results are important to understand the behavior and stability of the magnetic hardness created by Sm3+ doping in soft magnetic Mn–Zn ferrite ceramics. •Up to 25 kGy of γ-irradiation, Mn0.5Zn0.5SmxFe2-xO4 samples retain their cubic spinel structure.•For increasing γ-irradiation dose the lattice parameter decreases in each sample.•More defects are created and metastable Sm and Mn atoms are easily removed.•Magnetic anisotropy vanishes and super-paramagnetic behavior is seen.•The γ-irradiation degrades the magnetic properties of the samples.