Effect of alloying by gadolinium on the magnetic properties of irradiation-amorphized oxides of the Y3 − x Gd x Fe5O12 system

Abstract

Magnetometry and X ray diffraction have been used to study the structural state and magnetic properties of the system of oxides with an iron garnet structure, Y 3 -x Gd x Fe 5 O 12 (x = 0, 0.75, 1.5), in the course of amorphization via irradiation by fast neutrons. It has been established that the partial replacement of diamagnetic yttrium ions by paramagnetic gadolinium dramatically changes the behavior of the magnetic moment of the garnets during their gradual amorphization. The magnetic moment of the yttrium iron garnet decreases significantly with increasing fluence, whereas the magnetic moments of gadolinium alloyed gar nets, on the contrary, increase noticeably along with the simultaneous increase in the compensation temper atures of the sublattice magnetizations. The observed differences in the radiation behavior of the garnets are explained by the different behavior of the iron and gadolinium sublattices under irradiation. It is shown that the irradiation to a fluence of 3 × 10 20 cm -2 leads to a complete amorphization of all samples investigated. It has been established that the amorphous samples were in a spin glass state.

Iron Oxide-Based Nanostructures for MRI and Magnetic Hyperthermia

“…Moreover, different alloys of iron and other magnetic materials have been proposed to optimize the magnetic properties (e.g., [35,36]). Nevertheless, owing to limited biocompatibility such formulations are not suitable for biomedical applications.…”