Rearrangement in the local, electronic and crystal structure of europium titanates under reduction and oxidation

Magnetic interactions and the puzzling absence of any Raman mode in EuTiO3

“…Furthermore, the Raman spectra presented in Popov et al [ 38 ] fully agree with our observations of the complete absence of any peak in pure ETO, while in the mixed valence samples distinct peaks appear, [ 38 ] which are absent in our Raman spectra confirming that in the bulk of our polycrystalline ETO sample any presence of Eu +3 is very limited and we have a clear domination of Eu +2 . Furthermore, in Popov et al [ 38 ] it is pointed out that extreme caution should be exercised with respect to the laser power used in Raman measurements, because heating the sample in open air can act as an oxidizing atmosphere thus affecting the stability of Eu valence. This confirms our findings presented in Figure S3 regarding the effect of increased laser power to the Raman spectrum.…”

“…A detailed study about the synthesis of ETO samples with Eu +2 /Eu +3 mixed valence state has revealed valuable information about the structural properties of those compounds. [ 38 ] By comparing the very small parasitic peaks in Figure S4 inset of our synchrotron XRD results with those in figure 2b of Popov et al [ 38 ] we conclude that the contribution of the Eu +2 valence dominates the bulk of our polycrystalline sample. Furthermore, the Raman spectra presented in Popov et al [ 38 ] fully agree with our observations of the complete absence of any peak in pure ETO, while in the mixed valence samples distinct peaks appear, [ 38 ] which are absent in our Raman spectra confirming that in the bulk of our polycrystalline ETO sample any presence of Eu +3 is very limited and we have a clear domination of Eu +2 .…”

“…[ 38 ] By comparing the very small parasitic peaks in Figure S4 inset of our synchrotron XRD results with those in figure 2b of Popov et al [ 38 ] we conclude that the contribution of the Eu +2 valence dominates the bulk of our polycrystalline sample. Furthermore, the Raman spectra presented in Popov et al [ 38 ] fully agree with our observations of the complete absence of any peak in pure ETO, while in the mixed valence samples distinct peaks appear, [ 38 ] which are absent in our Raman spectra confirming that in the bulk of our polycrystalline ETO sample any presence of Eu +3 is very limited and we have a clear domination of Eu +2 . Furthermore, in Popov et al [ 38 ] it is pointed out that extreme caution should be exercised with respect to the laser power used in Raman measurements, because heating the sample in open air can act as an oxidizing atmosphere thus affecting the stability of Eu valence.…”

Crystallization kinetics and structural properties of nanocrystalline europium-yttrium-titanate (Eu0.5Y0.5)2Ti2O7

“…The non-uniform distribution of RE ions, increased defects, and lattice frustration can significantly modify the final material properties [9,10]. Inappropriate heat treatment can result in an undesirable transformation of the pyrochlore structure, such as that of perovskite [11].…”

Magnetic field driven phase transitions in EuTiO3

“…[8] The cubic to tetragonal structural phase transition close to room temperature is meanwhile well documented for ETO by various experimental studies. [1,[9][10][11][12][13][14] However, variations of sample quality, local structural disorder, [10] presence of Eu +2 /Eu +3 [15] , or oxygen vacancies [14] are known to slightly modify the structural phase transition temperature (T S ).…”