Ferromagetic-paramagnetic transformation in hydrogenated ferrous titanate

Ferrous titanate (FeTiO3) nanoparticles with hexagonal disc structure were prepared by a simple hydrothermal method. The VSM results show that ferromagnetic-paramagnetic transition of FeTiO3 caused by high temperature hydrogenation. The morphology and lattice structure of FeTiO3 was characterized in detail by XRD, Raman, SEM and TEM. It was found that the magnetic transition of FeTiO3 nanoparticles after hydrogenation could be attributed to the change of lattice structure and surface effect. Further research by XPS found that the high temperature hydrogenation treatment could cause the change of elemental valence states and oxygen vacancies concentration for FeTiO3. The weakening of double exchange interaction (Fe2+-O-Fe3+) and the reduction of uncompensated surface spin were the main cause of the ferromagnetic-paramagnetic transition. This experiment would provide a new idea for regulating the magnetic property of materials.