Mechano-Synthesized Orthoferrite Starting from Wüstite Assisted by SPS

Abstract

Stoichiometric mixtures of FeO and Y 2 O 3 were milled and heat treated to obtain yttrium iron garnet, Y 3 Fe 5 O 12. Two types of heating systems were used: one, a spark plasma sintering machine and the second, an electrical oven. The magnetic properties of the resulting specimens have been analyzed and discussed as a function of the grain size and the particles' morphology. The partial formation of garnet and orthoferrite phases was revealed on the obtained powder through microstructural analyses after 9 h of ball milling. The milled powders were transformed into the orthoferrite phase after the SPS-treatment at 700˚C and 900˚C. Magnetic-saturation studies revealed magnetic responses up to 12.7 emu/g for specimens SPS-treated at 700˚C, whereas 2.1 emu/g for samples SPS-treated at 900˚C. Conventionally treated specimens at 700˚C developed 0.36 emu/g of magnetization, while 0.93 emu/g was registered for those treated at 900˚C.