Size distribution of huntite-borate crystals grown by spontaneous crystallization from flux

Abstract

Rare-earth huntite-borates R(A1, Ga)3(BO3)4, where R = Yb, Er, and/or Nd, were grown by spontaneous crystallization from fluxes based on Bi2O3-B2O3. Crystals were removed from the melts and selected to different size fractions using meshes. It was found that dependence of weight for each size fraction on size in double logarithm coordinates was close to a symmetrical function. The dependence of logarithm of crystal amount on size was almost linear.Single crystals of borates RMe3(BO3)4 with the structure of the natural mineral of huntite CaMg3 (003)4, where R represents rare-earth elements or Bi and Me is Al, Cr, and Ga, have applications in nonlinear optics and laser engineering.1"6 A series of high-melting, chemically inert, and mechanically stable huntite-borate crystals were grown using fluxes based on K2Mo3O 10 1,2PbO-PbF2-B2O3,3 BaO-B2O3,4 Bi2O3-B2O3,5-8 and other systems. Tests with a large number of solvents1"8 led us to the choice of Bi2O3-B2O3 as the optimal one for obtaining huntite crystals because in this case the melt system consists of only cations which form huntite structure as host particles.7For preliminary studies of the dependence of optical and crystal-chemical properties on crystal composition, we used a simple crystal growth technique called spontaneous crystallization from a molten flux to give small crystals. In this communication we describe a procedure for growing relatively small single crystals of huntiteborates and discuss the distribution of prepared crystals by size.Although the study of size distribution of grown crystals was not our main goal, it seems to us that the data obtained are interesting for both fundamental and practical crystal growth.Four types of charges consisting of crystals and Bi2O3-B2O3 flux components were prepared. Melt compositions for runs 5-1, 6-2, 7-1, and 7-2 are given in Table I. Starting materials were (4-9's) oxide powders. Charges were weighed out and fractional amounts were placed in pure platinum crucibles of about 50 ml volume, and the crucibles were placed in a furnace. The furnace temperature was increased to T(l) °C over t{\) h, kept for t(2) h, and cooled to 7\2) °C for 30 min. For crystal growth, the melts were cooled slowly from T(2) °C to T(3) °C during t(3) h; after that melts with crystals were cooled to room temperature over 5-10 h. All temperature parameters are given in Table I.After the crystal growth process, crystals were removed from the melt by dissolving excess flux in hot HNO3 and water, and then were dried. The huntite structure for each batch of crystals was checked by x-ray powder diffraction analysis. The grown crystals with the huntite structure were mostly colored transparent hexagonal rods as shown in Fig. 1. Since cooling rates for all melt compositions were too high, the optical quality of the prepared materials was not as high. Moreover, as the given growth procedures shown in Table I were only preliminary ones, other growth parameters also were not optimized. The crystals contained many cracks which were formed during ...

Low-temperature magnetic phase diagram of HoFe3(BO3)4holmium ferroborate: a magnetic and heat capacity study

“…The family of rare-earth ferroborates with the general formula RA 3 (BO 3 ) 4 and huntite structure where R 3+ is a rare-earth or Y 3+ ion and A = Al, Ga, Sc, Cr or Fe have drawn the attention of researchers primarily as a medium for nonlinear optics and laser techniques [1][2][3]. However, the coexistence of two magnetic subsystems of iron and rare-earth ions coupled by the exchange interaction in RFe 3 (BO 3 ) 4 causes the interesting magnetic properties of this family of crystals.…”

Stacking Sequences of Coherent EuAl3(BO3)4 Polymorphs Define Local Eu3+ Symmetry and Control Access to Quantum Information Storage

“…Flux growths, though, inevitably introduce inclusions in crystals. In fact, for RX 3 (BO 3 ) 4 growths, Pb ions have been introduced by PbF 2 –B 2 O 3 flux, Bi ions by Bi 2 O 3 –B 2 O 3 flux, , and Mo ions by K 2 Mo 3 O 10 flux − at percent levels on cation sites.…”

Growth of ErAl3(BO3)4 Single Crystals from a K2Mo3O10 Flux

“…Rare-earth aluminum borate crystals (RAl 3 (BO 3 ) 4 ; R = Y, La−Lu) have attracted much attention, due to their potential applications in various industrial fields because of their excellent optical properties. − These RAl 3 (BO 3 ) 4 crystals are of great interest for their luminescence and very low concentration quenching. Nowadays, there is a persistent demand for optical devices, such as self-frequency-doubling lasers and laser diode pumps. ,,, Among these RAl 3 (BO 3 ) 4 crystals, YAl 3 (BO 3 ) 4 is well-known to be a nonlinear crystal and is an excellent host for rare-earth ions such as Nd 3+ , Yb 3+ , and Er 3+ .…”

“…Some attempts have been made to synthesize RAl 3 (BO 3 ) 4 crystals from high-temperature solutions using the binary or pseudo-binary systems K 2 SO 4 −3MoO 3 , , BaO−B 2 O 3 , BaCO 3 −B 2 O 3 , Bi 2 O 3 −B 2 O 3 , K 2 Mo 3 O 10 −B 2 O 3 16 and K 2 CO 3 −3MoO 3 10 and the pseudo-ternary system K 2 Mo 3 O 10 −Nd 2 O 3 −B 2 O 3 8 as fluxes. In addition, RAl 3 (BO 3 ) 4 crystals were grown by liquid-phase epitaxy, top-seeded solution growth. ,, Among these techniques, flux growth is very convenient and can produce ErAl 3 (BO 3 ) 4 crystals.…”

“…Rare-earth aluminum borate crystals (RAl 3 (BO 3 ) 4 ; R ) Y, La-Lu) have attracted much attention, due to their potential applications in various industrial fields because of their excellent optical properties. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] These RAl 3 (BO 3 ) 4 crystals are of great interest for their luminescence and very low concentration quenching. Nowadays, there is a persistent demand for optical devices, such as self-frequency-doubling lasers and laser diode pumps.…”