High-pressure synthesis, crystal structure and magnetic property of ilmenite-type FeGeO3

We synthesized well-crystallized ilmenite-type FeGeO3 to investigate its structural and magnetic properties. Ilmenite-type FeGeO3 were synthesized by high-pressure synthesis technique using a Kawai-type multi-anvil apparatus. Their structural and magnetic properties were examined by XRD analysis with Rietveld refinement, transmission electron microscopy, Mössbauer spectroscopy and SQUID-magnetization measurements. The subsequent annealing after the high-pressure synthesis was effective to improve the crystallinity of the ilmenite-type FeGeO3. The primary particle size of ilmenite-type FeGeO3 was ∼15 nm. Some particles seemed to be covered with non- or poorly crystalline phase even after the annealing, and others showed a lamellar microstructure parallel to the (0 0 1) plane. Theilmenite-type FeGeO3 showed typical antiferromagnetic behavior with the Néel temperature of 79 K.

Crystal structure, transmission electron micrograph and temperature dependent susceptibility of ilmenite-type FeGeO3.Figure optionsDownload as PowerPoint slideHighlights
► Ilmenite-type FeGeO3, a novel polymorphism of FeGeO3 was successfully synthesized.
► It was synthesized by using high pressure technique at 23.5 GPa at 500 °C.
► Subsequent annealing in vacuum was effective to improve the crystallinity.
► Its primary particle size was ∼15 nm, and some grains had lamellar microstructure.
► It showed typical antiferromagnetic behavior with the Néel temperature of 79 K.