Luminescence as an indication of distortion in A3+2 B4+2 O7 type pyrochlores

Relationship between structural characteristics and photoluminescent properties of (La1−xEux)2M2O7 (M=Zr, Hf, Sn) pyrochlores

“…The splitting widths (Dl ¼ l A Àl B ) increased with the distortion of the EuO 8 scalenohedra. This is consistent with the previous results that larger distortion of EuO 8 scalenohedra induces larger splitting widths of the 5 D 0 -7 F 1 transitions of Eu 3+ ions in A 2 B 2 O 7 :Eu 3+ (A ¼ La, Gd, Y, Lu; B ¼ Ti, Zr, Sn) pyrochlores [15].…”

“…McCauley and Hummel [15] indicated that the 5 D 0 -7 F 1 transitions of Eu 3+ in the D 3d symmetry occur along a specific direction. The 5 D 0 level has A 1g symmetry, and the 7 F 1 level should split into two components of A 2g and E g symmetry.…”

“…Eu 3+ -doped pyrochlores, A 2 B 2 O 7 (A ¼ Y, La, Gd; B ¼ Ti, Zr, Hf, Sn), have been reported as a promising candidate for phosphors [15][16][17][18]. In the pyrochore structure, Eu 3+ ions prefer to substitute the A 3+ sites, because the Eu 3+ ion has the same valence state as that of the cations at the A site, and the ionic radius of the Eu 3+ ion is close to those of Y 3+ , La 3+ and Gd 3+ ions.…”

Comparative ab initio study of electronic, optical and chemical bonding properties of pyrochlores, Y2B2O7 (B=Ti4+, Sn4+)

“…Although the optical properties of Eu 3 + [1] and Cr 4 + [2] in the pyrochlores, Y 2 B 2 O 7 (B¼ Sn 4 + , Ti 4 + ) have been described in the literature, there had been no satisfactory interpretation of the following experimental results until recently [3,4]: the crystal field splitting of Eu 3 + 7 F 1 level is larger in Y 2 Sn 2 O 7 than in Y 2 Ti 2 O 7 ; the average crystal field splitting of the six-fold coordinated Cr 4 + ion is larger in Y 2 Sn 2 O 7 than in Y 2 Ti 2 O 7 ;…”

Effect of in situ applied electric field on the growth of La2Ti2O7 thin films by chemical solution deposition

“…It was revealed that pyrochlore (PY) La 2 Ti 2 O 7 has a high Curie temperature and a high coercive field [3,4]. With further research, applications of La 2 Ti 2 O 7 as catalysts, high-temperature transducers, and hosts of fluorescence centers were reported [5,6]. Moreover, it also exhibits a low dielectric loss at microwave frequencies.…”