Swift heavy ion irradiation-induced modifications in structural and electrical properties of Y3+-substituted yttrium iron garnet

The consequences of 50 MeV Li³⁺ ion irradiation (fluence: 5×10¹³ ions/cm²) on the structural and electrical properties of the Y_3+xFe_5?xO₁₂ (x=0.0, 0.2, 0.4 and 0.6) garnet system have been investigated over the temperature range of 300–673 K. It is found that the percentage formation of an additional yttrium orthoferrite phase observed along with the bcc garnet phase considerably reduces for x=0.4 and 0.6 compositions after swift heavy ion (SHI) irradiation. The nature of thermal variation of DC resistivity curves for x=0.0 and 0.2 compositions is different from that for x=0.4 and 0.6 compositions. The SHI irradiation influences the magnitude of DC resistivity and conduction mechanism for the single-phase compositions while for mixed-phase compositions they remain unaffected. The results have been explained in the light of replacement of magnetic (5μ_B), smaller (0.64 Å), Fe³⁺ ion by nonmagnetic (0μ_B), larger (0.89 Å), Y³⁺ ion, the presence of the yttrium orthoferrite phase and swift heavy ion irradiation-induced paramagnetic centers in the system.