Mechano-Synthesized Orthoferrite Starting from Wüstite Assisted by SPS

Abstract

Stoichiometric mixtures of FeO and Y2O3 were milled and heat treated to obtain yttrium iron garnet, Y3Fe5O12. 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.