Structural, thermal, 57Fe and 151Eu Mössbauer studies of Eu2O3–Fe2O3 ceramic nanostructures

Study of the photocatalytic activity of Fe3+, Cr3+, La3+ and Eu3+ single-doped and co-doped TiO2 catalysts produced by aqueous sol-gel processing

“…Clearly the particles herein are much smaller as no magnetic hyperfine splitting is observed. Furthermore, the most likely origin of the small minority singlet is nanocrystalline europium orthoferrite, closely matching the reported isomer shift of 0.32 mm/s [35], because (super)paramagnetic europium iron garnet would exhibit two lines with isomer shifts of 0.13 and 0.35 mm/s [34].…”

“…Considering the occurrence of this component with increasing Eu content, and because Mössbauer spectroscopy is a local probe technique, one might speculate that a ternary Eu-Fe-O phase is formed with a cubic coordination for iron that yields a vanishing quadrupole splitting and thus a singlet component. The Eu 2 O 3 -Fe 2 O 3 system has been investigated earlier by both Fe-57 and Eu-151 Mössbauer spectroscopy [34,35]. In bulk form, the europium orthoferrite EuFeO 3 and the europium iron garnet Eu 3 Fe 5 O 12 are the most likely phases to form.…”

“…In bulk form, the europium orthoferrite EuFeO 3 and the europium iron garnet Eu 3 Fe 5 O 12 are the most likely phases to form. Both phases exhibit a magnetic hyperfine splitting at ambient temperature [34,35], even in nanoparticle systems obtained by ball-milling [35] with a crystallite size of 9 nm. For the latter smallest particles, a small fraction of paramagnetic iron is observed but with a rather large quadrupole splitting of ~0.9 mm/s [35].…”