Formation of SrVO 3 precursors from Sr(OH) 2 and V mO n ( [formula omitted]) by mechanical stressing under ambient or reducing atmosphere

Abstract

Mechanochemical and subsequent heating processes to produce SrVO 3 are studied, starting from a mixture of Sr(OH) 2 and V m O n (2/5≦ m/n≦2/3) by milling and heating in an ambient or reducing atmosphere. Single phase perovskite SrVO 3 was obtained by firing the milled mixtures at 1300°C under reducing atmosphere with four dehydration steps via two intermediates, Sr 2V 2O 7 and Sr 8V 8O 25. The fourth dehydration step, corresponding to transformation of Sr 8V 8O 25 to SrVO 3, appears at around 1100°C by heating mixtures containing trivalent vanadium and milled in a reducing atmosphere. Dehydration of the mixtures was promoted by milling under N 2–4% H 2, due to reduction of precursors by hydrogen. The precursor from the mixture with III–V mixed-valent vanadium milled under N 2–4% H 2 is closer to the final product SrVO 3 than any other precursors.