Growth and evaluation of lanthanoids orthoniobates single crystals processed by a miniature pedestal growth technique

Abstract

Optimized conditions for the growth of lanthanoids orthoniobates (LnNbO 4 , Ln = lanthanide elements) single crystal minirods by a floating zone technique were investigated. Adequate atmospheres and pulling to feeding speed ratios to grow these materials were determined. Emphasis is given to the study of LaNbO 4 because of their more favorable growth conditions and crystalline quality. This material can be efficiently doped with rare earth elements such as erbium. It grows with high crystallinity and its preferential growth direction is [1 1 0]. A preliminary evaluation of optical properties of Er 3+ -doped LaNbO 4 single crystal under the JuddOfelt formalism indicates spectral parameters Ω t close and even larger than for Er 3+ ions in YVO 4 .

Crystal growth and characterization of tetragonal tungsten bronze FerroNiobates Ba2LnFeNb4O15

“…In the case of SmFNO and EuFNO, yellowish and white fine powders were observed at the bottom of aggregates, respectively. XRD analysis specifically performed on crushed crystals revealed the presence of LnNbO 4 , a rare earth orthoniobate that crystallizes in the fergusonite structure [20]. Moreover the presence of black powder and micron-sized crystals was also detected by powder XRD and identified as barium hexaferrite, BaFe 12 O 19 .…”

Hydrothermal approach and luminescent properties for the synthesis of orthoniobates GdNbO4:Ln3+(Ln = Dy, Eu) single crystals under high-temperature high-pressure conditions

“…Lanthanide orthoniobates have been extensively studied in recent years because of their environmental and energy related applications, 1,2 which are based on their characteristic high chemical and electrochemical stabilities, photo-electronic activity, ion conductivity and luminescence. [3][4][5][6] For example, they can be used as phosphors for solid-state lighting, 7,8 photocatalysts for both contaminant degeneration and H 2 production, [9][10][11] chemically robust hosts for nuclear materials and wastes, and ion conductors in lithium batteries or solid-oxide fuel cells.…”

“…[22][23][24][25] Additionally, this method is simple with low cost and very good productmorphology control. 26 Furthermore, compared with the traditional solid method, the synthesis under high pressure has two prominent advantages: (1) the decrease of interatomic distances in existing materials; (2) densification effect during the synthesis of new materials, stabilization of precursors, compressing of the corresponding atoms to increase the reactivity. 27 Therefore, a hydrothermal process under high pressure has become an efficient way for many researchers to obtain LnNbO 4 single crystals in this field.…”

Tuning Green to Red Color in Erbium Niobate Micro- and Nanoparticles

“…Indeed, these materials exhibit low phonon cut-off energies, which make them suitable for optical applications, as the transition probability of the intra-4f n is enhanced in such case, also presenting long emission lifetimes [2,5]. Several RE ions have been employed in the formation of RE niobate materials (RE = La, Ce, Pr, Nd, Sm, Eu, Dy, Ho, and Er) [1,3,[6][7][8][9][10] and their luminescence properties have been widely investigated. Among those, erbium niobates possess interesting properties for optical applications owing to the trivalent Er ion (Er 3+ ) characteristics [11,12].…”