Dielectric anomalies in Nd3+ doped Ba2NaNb5O15 laser crystal

Formation of Ba2NaNb5O15 Crystal and Crystallization Kinetics in BaO–Na2O–Nb2O5–SiO2–B2O3 Glass

“…Concerning the crystal size of early stage crystallization at different isothermal temperatures, in the thermodynamic point of view, an incubation time is dependent on the combination of driving force (increase with deep undercooling) and viscosity (decrease with increasing temperature) for nucleation. From the simple model of crystal formation energy in glass, G = 4/ 3πr 3 Δg + 4πr 2 γ, where r is the crystal radius, Δg is the free energy difference between glass and crystal at a given temperature, γ is the surface energy of a grain, the critical nucleus size, which can be thought as a grain formed at the incubation time, is obtained as 2γ/Δg. 23 In this thermodynamic reason, we can say that the crystal size at the incubation time becomes smaller with increasing undercooling (large Δg, low isothermal temperature).…”

“…Barium sodium niobate (Ba 2 NaNb 5 O 15 , BNN) crystal has attracted attention for a long time because of its important physical properties of ferroelectricity, high nonlinear optical coefficient, and intense photoluminescence. − BNN crystal possesses a sequence of structural phase transitions accompanying the change of dielectric properties. The ferroelectric orthorhombic Pba 2 structure BNN with the lattice parameters a = 12.425, b = 12.484, c = 3.997 Å at room temperature transforms to the ferroelectric tetragonal 4mm at 260 °C, and with further heating, to the paraelectric tetragonal 4/ mmm at 560 °C. , At room temperature, BNN has the useful values of dielectric constant ε = 250 and spontaneous polarization P = 0.40 C/m 2 , which can be compared with those of LiNbO 3 (ε = 80, P = 0.71 C/m 2 ), , LiTaO 3 (50, 0.5 C/m 2 ), BaTiO 3 (3000, 0.25 C/m 2 ) .…”

Crystallization and optical properties of Nd3+ doped ferroelectric glass-ceramics in the barium sodium niobosilicate system

“…Later, enhancement of its dielectric property has been attempted by employing alternative preparing method [9]. On the other hand, barium sodium niobate crystals show interesting potential applications for solid state devices [10], optical communication [11] and laser crystals [12].…”

“…In order to fabricate ferroelectric crystals to suite the applications as optical materials, doping with rare earth elements is always employed [11][12][13][14][15]. Among the rare earths, Nd 3 þ has been extensively used as a laser active ion in several hosts [16,17], and the Nd 3 þ ions are also good candidates for upconversion luminescence and lasers [18][19][20].…”

Preparation of textured K2BiNb5O15 ceramics with rod-like templates by the screen-printing technique

“…As one of the most representative materials, barium sodium niobate (Ba 2 NaNb 5 O 15 , abbreviated as BNN) has been widely researched [4][5][6]. K 2 BiNb 5 O 15 (KBIN) exhibits the same tungsten bronze type structure as BNN and possesses large piezoelectric properties in both the longitudinal and transverse directions, the polar axis is along 0 0 1 with only one phase transition (∼420 • C).…”