High field magnetization of single crystals YFe2O4, YbFe2O4 and LuFe2O4

Microstructure and Magnetic Properties of Metastable RFeO3 (R: Rare‐earth element) Formed from Undercooled Melt

“…These results also indicate that volume fraction of the YFeO 3 phase decreases with decreasing due to the existence of YF 2 O 4 and Y 3 Fe 2 O 7 along with the magnetic phases such as Fe 3 O 4 and Fe. The magnetic transitions for the h ‐YFeO 3 , Y 3 Fe 2 O 7 , and YFe 2 O 4 were not detected due to the paramagnetic behavior . The similar magnetic transition was also confirmed in the ErFeO 3 sample solidified under the of 10 5 , 10 3 , and 10 −1 Pa. From the above results, we can expect that the volume fraction of the YFe 2 O 4 and Y 3 Fe 2 O 7 phases would decrease with decreasing , and only Y 2 O 3 and FeO and/or α‐Fe would be formed as the nonequilibrium phases at lower than 10 −1 Pa.…”

“…The change in the crystal structure from orthorhombic to hexagonal was identified depending on . On the other hand, it has been reported that the h ‐RFeO 3 hexagonal structure with a space group of P 6 3 cm and Fe 2+ ‐containing RFe 2 O 4 compounds are suggested to show ferroelectricity because of the slightly distorted oxygen packing, i.e., noncentrosymmetric structure . The oxygen deficiencies and thermodynamic stabilities of the constituent phases were studied in the temperature range from room temperature to 1673 K under the controlled using TG‐DTA.…”

Ferroelectricity from iron valence ordering in rare earth ferrites?

“…2 and 3a), with a remanent magnetic moment after cooling in strong magnetic fields between 1.5 (Y) and 2.8 µ B /f.u. (Lu) [105]. Frequency-dependence in ac magnetic susceptibility is observed below about 220 − 250 K, with detailed analyses suggesting either spin-glass- [106] or clusterglass-like [107,108,109] freezing, with large clusters of size ∼ 100 nm in-plane directly observed by magneticforce-microscopy in one example [107].…”

Effect of Oxygen Partial Pressure on the Formation of Metastable Phases from an Undercooled YbFeO3 Melt Using an Aerodynamic Levitator

“…This transition confirmed the existence of Fe 3 O 4 and α‐Fe. However, only Fe 3 O 4 was detected in the samples annealed above 1200 K. These results mean that the gradual decrease of the magnetization in the temperature range from 848 to 1043 K indicates that the α‐Fe phase was oxidized to Fe 3 O 4 and the oxidation of Fe to Fe 3 O 4 was completed at temperatures above 1200 K. The T c for the h ‐YbFeO 3 and YbFe 2 O 4 were not detected due to the paramagnetic behavior 9,10,20,21 . The reproducibility of the magnetization curve has been confirmed.…”

“…In the R–Fe–O system, metastable hexagonal RFeO 3 and RFe 2 O 4 have been reported to exhibit ferroelectricity. For the system containing iron ions, oxygen nonstoichiometry will lead to the formation of defects combined with the valence state of iron ion, because the iron valence is strongly dependent on the oxygen partial pressure 9–12 …”