Preparation and physical properties of LuFe2O4±x polycrystalline samples with different oxygen contents

LuFe 2 O 4± x polycrystalline samples with different oxygen contents were synthesized via a conventional solid-state reaction under controlled CO 2 /H 2 mixed gas atmospheres, and the oxygen contents were determined by thermogravimetric analysis. The effect of oxygen partial pressure on the structural, magnetic, and electrical transport properties was systematically investigated. X-ray diffraction results show that a relatively pure LuFe 2 O 4 phase can be obtained within a wide range of CO 2 /H 2 ratios from 1.8 to 7.0. The lattice parameters remain nearly unchanged with varying oxygen content, whereas the average grain size gradually decreases as the CO 2 /H 2 ratio increases. Magnetic susceptibility measurements reveal that both the magnetic transition temperature and the magnitude of susceptibility increase with increasing CO 2 /H 2 ratio. In contrast, room-temperature resistivity shows no significant change and remains within the same order of magnitude for all samples.