Anisotropy of two-photon excited f–f transitions of Eu2+ in KMgF3

Francini, R.; Grassano, U. M.; Boiko, S. A.; Tarasov, G. G.; Scacco, A.

doi:10.1063/1.478106

Cited by 13 publications

(19 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Scacco et al [35] reported that, in 'as-grown' KMgF 3 crystals doped with YbF 3 containing Yb 3+ ions, only Yb 2+ ions are created without any reduction procedure and Yb 3+ ions are not present. The same was observed for 'as-grown' KMgF 3 crystals doped with EuBr 3 or EuCl 3 , where divalent Eu 2+ ions are created and trivalent Eu 3+ ions are not present [35][36][37]. Why does such a difference occur between the 'as-grown' CaF 2 and KMgF 3 in spite of the fact that a powder containing trivalent rare-earth ions is added in the growing process for both samples?…”

Section: The Presence Of Y B 3+ Ions In As-grown Crystalsmentioning

confidence: 74%

Optical study of Yb³⁺/Yb²⁺conversion in CaF₂crystals

Kaczmarek

Tsuboi

Ito

et al. 2005

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

Yb(3+) ions with various site symmetries have been observed in the absorption and emission spectra of Yb(3+):CaF(2) crystals, both γ-irradiated and annealed in hydrogen. The absorption intensity value is found to be much higher for the γ-irradiated crystal and strongly dependent on the gamma dose. The UV absorption spectra of γ-irradiated and H(2)-annealed CaF(2):5 at.% Yb(3+) crystals are quite similar. Yb(2+) absorption bands are observed at 360, 315, 271, 260, 227 and 214 nm, which are called A, B, C, D, F and G bands, respectively. For γ-irradiated CaF(2):30 at.% Yb(3+), an additional band at 234 nm can be seen. It is suggested that only a negligible amount of Yb(3+) ions are converted into Yb(2+) under the γ-irradiation. The presence of Yb(2+) is confirmed by the 565 and 540 nm luminescence under 357 nm excitation. It is also suggested that the excitation in the A, C, D and F absorption bands of Yb(2+) gives rise to photo-ionization of Yb(2+) ions and electrons in the conduction band to form the excited Yb(3+) ions which emit IR Yb(3+) luminescence.The UV absorption and emission spectra obtained for γ-irradiated and H(2)-annealed crystals have different structures. This suggests that different mechanisms are responsible for the creation of Yb(2+) ions. γ-irradiation favours Yb(2+) isolated centres by reduction of Yb(3+) ions located at Ca(2+) lattice sites, whereas annealing in hydrogen favours Yb(2+) centres neighbouring Yb(3+) ions when a Yb(3+) ion pair captures a Compton electron. Also, γ-irradiation does not change the position of Yb(3+) ions converted into Yb(2+) in the CaF(2) lattice. In the case of H(2) annealing, a Yb(3+) ion converted to Yb(2+) is shifted to the Ca(2+) position in the lattice.

show abstract

Section: The Presence Of Y B 3+ Ions In As-grown Crystalsmentioning

confidence: 74%

Optical study of Yb³⁺/Yb²⁺conversion in CaF₂crystals

Kaczmarek

Tsuboi

Ito

et al. 2005

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

show abstract

“…Seo et al 32 assigned the emission at 322 nm to the cubic site of Eu 2+ , whereas the emission at 359 nm was assigned to both the cubic and non-cubic sites of Eu 2+ . Francini and group 30,38 indicated the presence of Eu 2+ at both cubic and trigonal sites. On the other hand, Tsuboi 45 reported different site symmetries for Eu 2+ , i.e., cubic, trigonal and tetragonal ones, based on absorption spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

“…24 This has motivated a large number of experimental studies to investigate and explain the optical properties of Eu-doped KMgF 3 in the last few years. 25–50 However, existing literature shows different opinions related to the origin of the observed optical behaviour of Eu-doped KMgF 3 . The first and most common issue is related to the assignment of a particular optical peak.…”

Section: Introductionmentioning

confidence: 99%

“…The last but not least issue is related to the oxidation state of Eu in KMgF 3 . A few groups believed the presence of either Eu 2+ 26,30,32,38,42,45 or Eu 3+ , 47–50 while some groups reported that Eu exists as both Eu 2+ and Eu 3+ . 31…”

Section: Introductionmentioning

confidence: 99%

“…Most of the studies indicated the crucial role of different point defects in the optical properties of Eu-doped KMgF 3 . However, some groups believed the role of only cationic 29,30,38 or anionic vacancy, 25,31 while some groups reported the involvement of both cationic and anionic vacancies. 37,50 The third issue is regarding the site selectivity of Eu in the host crystal structure.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations