Raman active phonon and crystal-field studies of Yb3+ doped NdVO4

Cooperative emission study in ytterbium doped NdVO4

“…These phonons compensate for the mismatch between the excitation energy and the Yb 3 + CF levels as detected for the two occupation sites (see Ref. [14]). Same excitation processes with the 9394 cm À 1 Nd:YAG laser excitation implying optical phonons have been reported for Yb 3 + doped tellurite glasses and their blue cooperative emission [20].…”

“…Single crystals of NdVO 4 doped with Yb (Yb x Nd 1 À x VO 4 where x ¼1%, 5%, 10% and 15%) were prepared by the flux growth method as described in Ref. [14,9] and transparent crystals with an average size of 3 Â 2 Â 1 mm 3 elongated in the direction of the crystallographic c axis of the tetragonal structure were obtained.…”

“…Neither defects nor local modes were detected and the phonon frequencies were linear between the end members YbVO 4 and LuVO 4 , NdVO 4 . In the case of Yb:NVO, the observed Yb 3 + CF infrared active bands corresponded to two site occupations, namely Nd substitutional site and interstitial octahedral site [14].…”

“…The J values are comparable with those reported for Yb 3 + -Yb 3 + in (Yb:LVO) [13] and for Nd 3 + -Nd 3 + pairs in YVO 4 and YLiF 4 [15]. In the case of Yb:NVO, the pair satellite absorption bands correspond to D (site I)¼1015271 cm À 1 and D (site II)¼101707 1 cm À 1 for the isolated Yb 3+ ions with their associated J constants À6.5, 7 and À 11.5, 6.5 cm À 1 (71 cm À 1 ) for sites I and II, respectively [14].…”

“…Recently, Yb 3 + ion 2 F 7/2 ground states and 2 F 5/2 excited states in Yb-doped LuVO 4 (Yb:LVO) and NdVO 4 (Yb:NVO) have been measured, as a function of doping concentration, by infrared absorption and luminescence [13,14]. Also, the Raman active phonons were detected and analyzed in order to determine the doping effects on the crystalline quality and the phonon contributions to the crystal-field vibronics.…”