44 results about "Flux growth" patented technology

The invention relates to a BaCa4Se7 compound, a BaCa4Se7 nonlinear optical crystal, a preparation method and application. The BaCa4Se7 compound is prepared by adopting a solid-phase reaction, and the BaCa4Se7 nonlinear optical crystal is grown by adopting a high-temperature melt spontaneous crystallization method, a flux growth method or a Bridgman method. In the growth of the BaCa4Se7 nonlinear optical crystal, the crystal is easy to grow and transparent and has no package and the advantages of higher growing speed, low cost, easy obtaining of a crystal in a larger size, and the like. The obtained BaCa4Se7 nonlinear optical crystal has the advantages of wider optical transparency range, larger hardness, good mechanical property, difficult cracking and deliquescence, easy processing and storage, and the like. The BaCa4Se7 nonlinear optical crystal can be used for preparing a nonlinear optical device.

The invention relates to a growing method of a fluxing agent of CsLiB6O10 crystals; the CsLiB6O10 and the fluxing agent are mixed according to molar ratio and carried out by pretreatment, thus obtaining a melt; the flux is M'X, M''X2, PbO, Bi2O3, M'3Mo3O10 or M'4V2O7, wherein, M' is Li, Na or K; M'' is Ca, Ba or Pb; X is F or Cl; the melt lowers to 2-10 DEG C above the saturated temperature, added with seed crystals and lowers to the saturated temperature after constant temperature; and the saturated temperature becomes initial temperature and the temperature lowers at the speed ratio of 0.01-1 DEG C / day; after the crystals grow to required size, seed rod crystals are lifted out of solution and reduced to room temperature at the speed ratio below 20 DEG C / h, thus obtaining the CsLiB6O10 crystals. The method can lower growth temperature, reduce the volatility and viscosity of a growth system, is beneficial for solute transporting and can grow optical crystals with high optical quality.

The invention relates to a preparation method of strontium fluoroborate nonlinear optical crystals, and applications of the strontium fluoroborate nonlinear optical crystals. Compound synthesis is realized via solid phase reaction, and crystal growth is realized via flux growth method. The preparation method is simple in operation, and low in cost. The obtained strontium fluoroborate nonlinear optical crystals will not deliquesce in the air, possesses excellent mechanical properties and stable physico-chemical properties, is unbreakable, is convenient for processing, and is suitable for preparation of nonlinear optical devices. Frequency-doubled effect of the strontium fluoroborate nonlinear optical crystals obtained by the preparation method is three times of that of KDP, and the strontium fluoroborate nonlinear optical crystals can be widely used in nonlinear optical devices such as double frequency converters and optical parametric oscillators.

The invention relates to a borate birefringent crystal for an ultraviolet band. The chemical formula of the borate birefringent crystal is KBaSc(B3O6)2 and belongs to a trigonal system; an atom K and an atom Ba in a crystal structure are in disordered mixed occupation; a space group is R-3 and a cell parameter Z is 3; the transmission range is 184-3000 nm; a calculated value n0 of the refractive index at gamma of 589 nm is 1.6168, ne is 1.5079 and delta n is 0.1089; the crystal grows by using a self-melting and spontaneous crystallization method or a flux growth method; the crystal is easy to grow, cut, grind, polish and preserve, is stable in the air, is uneasy for deliquescence and is insoluble in water; the crystal can be used for making polarization beam splitters such as Glan prisms, Wollaston prisms, Rochon prisms or beam splitting polarizers; and the crystal is importantly applied to the optical and communication fields.

The invention relates to a K3Al2(PO4)3 non-linear optical crystal as well as a preparation method and application thereof. The crystal belongs to a rhombic system and has a space group of Pna21, and the cell parameters of the crystal are described in specifications of the invention. The preparation method of the crystal adopts a flux growth method to grow the crystal and mainly comprises the steps of: preparing materials of K3Al2(PO4)3:K2O:P2O5 by the molar ratio being 1: (0.5-1.5): (0.5-1.5); putting in a muffle furnace for heating and melting; and then putting in a single crystal growth furnace for growing the crystal by using a seed crystal method. The K3Al2(PO4)3 crystal has the advantages of large non-linear optical effect, wide light transmission range of 180-2500nm, good mechanical property, no deliquescence and easy processing and preservation and the like, can be used for preparing non-linear optical devices and meet the demands of frequency conversion of laser in a blue-green light band and an ultraviolet light band.

The invention relates to a Ba3BP3O12 crystalloid, a growing method and the application thereof, belonging to the field of crystalloid growth. The Ba3BP3O12 crystalloid of the invention has the chemical formula composition of Ba (1-x-2y-2z) M (X) M (y)A (y) M (Z) 3 BP3O12, wherein, x, y and z are less than or equal to 0.35 and more than or equal to 0; M is one ion or a plurality of ions in Sr, Ca, Mg, Be, Zn, Eu, Mn and Yb which have +2 valent state; the M is one ion or a plurality of ions in Cr, Bi, Ti, Ce, Pr, Nd, Sm, Eu, Dy, Ho, Er, Tm and Yb which have +3 valent state; A is one ion or a plurality of ions in Li, Na, K, Rb and Cs; and M is one ion or a plurality of ions in Cr, Ti, Zr and Hf which have +4 valent state. The crystalloid produced by a flux growth method has the advantages of great hardness, good mechanical property, difficult cracking and deliquescence, easy processing and storing and the like, so as to be applied to the fields such as laser crystal, acousto-optic crystal, photorefractive crystal or photonic crystal.

The invention relates to a compound boron rubidium sulfate, a boron rubidium sulfate crystal and a preparation method thereof. The chemical formula of the compound is Rb5BS4O16, the molecular weight is 822.40, the chemical formula of the compound boron rubidium sulfate crystal is Rb5BS4O16, the molecular weight is 822.40, the compound boron rubidium sulfate crystal belongs to a tetragonal system, the space group is P43212, the cell parameters are as follows: a is equal to 10.148(4) A0, c is equal to 16.689(14) A0, Z is equal to 4, V is equal to 1718.8(17) A3, the boron rubidium sulfate compound is prepared by a solid reaction process, the compound is used for growing crystal through a flux growth method to obtain the boron rubidium sulfate crystal, the prepared crystal has a large dimension of at least centimeter level, and the crystal has the advantages of wide transmission waveband, fast preparation speed, simplicity in operation, short growth period, good mechanical property and easiness for processing, and the like.

The invention discloses a method for preparing a fluorescent material, namely a method for synthesizing Gd2O2S: Tb fluorescent powder and a flux composition used by the method. A co-precipitation method is adopted to prepare a precursor, and then the Gd2O2S: Tb fluorescent powder is prepared through a high-temperature solid-phase reaction. A flux growth method used by the method can reduce the growth temperature of crystals, and is easy for industrialized operation; the selected flux composition can remarkably improve the crystal shape and particle size distribution of the fluorescent powder; the obtained crystals have integral structures and less defects; and the method reduces the synthesis temperature of the high-temperature solid-phase reaction of the Gd2O2S: Tb fluorescent powder, improves crystal structures and the particle size distribution of the fluorescent powder, and ensures that the luminous brightness and service performance of the fluorescent powder are further improved.

The invention provides a flux growth of trigallium phosphate crystal. The method comprises weighing ammonium dihydrogen phosphate, gallium oxide, lithium carbonate and molybdenum oxide at the weight ratio of 1:2.44:(1.96-4.41):(11.45-25.77), mixing thoroughly, placing in a platinum crucible, heating for smelting in a growth furnace, cooling down to a temperature 10-20 DEG C above the saturation point of melt to obtain a mixed fusant composed of Ga3PO7 and flux, introducing a seed crystal into the growth furnace, feeding the seed crystal until the temperature drops to 1-2 DEG C above the saturation point and rotating at a speed of 30 r / min, cooling until the seed crystal begins to melt, taking out the crystals from the melt when the crystal growth stops, cooling down to 200 DEG C at a rate of 20-30 DEG C per hour, and naturally cooling down to room temperature to obtain centimeter-sized Ga3PO7 crystal. The invention has the advantages of simple equipment, rapid growth rate, easy operation, and yield of large-size Ga3PO7 with good optical quality.

The invention relates to a flux growth method and an application of a cesium tungsten-tellurite crystal. The cesium tungsten-tellurite crystal has a chemical formula of Cs2TeW3O12 and belongs to a hexagonal system, the space group refers to P63, the ultraviolet-visible-near infrared transmission spectrum and intermediate infrared transmission spectrum show that the crystal can penetrate through a wavelength range of 430-5350nm, and the transmittance can be over 80 percent under the uncoated condition; an infrared laser incidence crystal with the wavelength of 1064nm generated by using an Nd:YAG laser generates strong green light. Compared with the Cs2TeW3O12 polycrystalline synthetic technology reported in the existing literature, a flux growth method for growing high-quality Cs2TeW3O12 single crystals is provided at first internationally, the crystal structure is successfully analyzed, and the Cs2TeW3O12 single crystal of which the size is enough to meet the application is obtained.

A method and apparatus for bulk Group-III nitride crystal growth through inductive stirring in a sodium flux growth technique. A helical electromagnetic coil is closely wound around a non-conducting cylindrical crucible containing a conductive crystal growth solution, including both precursor gallium and sodium, wherein a nitrogen-containing atmosphere can be maintained at any pressure. A seed crystal is introduced with the crystal's growth interface submerged slightly below the solution's surface. Electrical contact is made to the coil and an AC electrical field is applied at a specified frequency, in order to create eddy currents within the conductive crystal growth solution, resulting in a steady-state flux of solution impinging on the submerged crystal's growth interface.

The invention discloses a nonlinear optical crystal material Sr3Y3BiB4O15 and a preparation method and application thereof. The crystal material is bismuth yttrium strontium borate shown as the chemical formula of Sr3Y3BiB4O15, belongs to a hexagonal system, and has the space group of P63 and the unit cell parameters of a=10.6975(13)A and c=6.7222(12)A. A crystal structure comprises BO3 radicals which are arranged in accordant direction and a BiO3 radical with lone pair electrons which are arranged in accordant direction, so that nonlinear effect is 3 to 5 times that of KH2PO4. A crystal has moderate hardness, is free from being deliquesced or cleaved, and is easy to cut, polish and store. The crystal grows by a flux growth method. The preparation method comprises the following steps of: mixing bismuth yttrium strontium borate and a fluxing agent; heating the mixture to obtain solution; stirring; preserving heat; cooling until the temperature is 0.5 to 3 DEG C above a saturation point; adding crystal seeds; controlling an appropriate temperature lowering speed; when the crystal grows to a certain degree, extracting the crystal out of a liquid surface; and slowly lowering the temperature to room temperature so as to obtain Sr3Y3BiB4O15 monocrystal. The crystal can serve as a frequency doubling crystal in an optical parametric oscillator and a harmonic generator. Moreover, the crystal comprises a yttrium element, so that other rare earth ions can be doped so as to obtain a self-frequency-doubling laser crystal.

This invention relates to a growing method for a flux of a non-linearity optical crystal including preparing materials according to the mol ration of 1;5-7.54 : 2.3-3.5: 8.75-35 of Na3La9B8027:Na20:B203 :NaF pre-processing, then rising the temperature in a crystal growing furnace till the complete melt, in which, the constant temperature uniforms the solution fully then introducing inoculating crystals above the saturation temperature of 5-20deg.C and keeping constant for 10-30mitutes then reducing the temperature quickly to the saturated, controlling the parameters to grow crystals, then the crystals break away from the surface to reduce the temperature to the room in the rate not greater than 50deg.C / h to get the crystal.

The invention relates to an yttrium phosphate double-refraction crystal and a growing method and application thereof. The crystal has the chemical formula of YPO4, belongs to a tetragonal system, and has the space group of I4[1] / amd, the cell parameter a of 6.8947 angstroms, the cell parameter c of 6.0276 angstroms, the cell parameter V of 286.533 angstroms<3> and the cell parameter Z of 4. The crystal is used for infrared-deep ultraviolet wave bands, is a single-axis crystal, and has the transmission range of 150-3300 nm; the double-refraction difference delta n of n[e] and n[o] ranges from 0.18 to 0.22, and the large-size yttrium phosphate crystal grows through a high-temperature melt method (melt pulling method or melt top seed solution method) or a flux growth method. The yttrium phosphate crystal obtained through the method is large in size, short in growth cycle, wide in light transmission range, high in transmission rate, large in double-refraction coefficient, and easy to cut, polish, machine and store. The crystal is a wide-waveband double-refraction optical material and can be used for manufacturing an optical fiber isolator, an annular mirror, a beam displacer, a beam splitter, a Glan polarizer and other polarizing devices and has important application in the fields of optics and communication.

The invention discloses a Ca, Mg, Zr, Gd and Ga garnet doped with Sm and a melt method crystal growth method thereof, the molecular formula thereof is Smz: Gd(3-x-z)CaxGa(5-x-2y)MgyZr(x+y)O12 (0<x<3,0<y<2.5, 0<z<3, 0<x+2y<5, 0<x+z<3), and the method comprises the following steps: the well-prepared raw materials are mixed fully, pressed and shaped, calcined in high temperature to obtain the starting raw material for crystal growth; the starting raw material is placed into a pot, heated and fully melt to obtain the initial melt of the melt method crystal growth, and is subjected to directionalor nondirectional growth on crystals by a melt method such as a traditional pulling method, a Bridgman-Stockbarge method, a flux growth method and the like to obtain solid laser working substances ofblue light pumping. By the invention, laser crystal with large size, even optical quality and fine performance can be obtained, which also can be used as solid laser working substances of blue light pumping and has the possibility of being used in fields such as medical diagnosis, material treatment, high density information reading and writing, monitoring and controlling, large screen color display, high definition color televisions and the like.

The invention provides a top seed reentry technique in flux growth, which belongs to the technical field of functional crystal materials. The top seed reentry technique is characterized in that: (1) a well processed seed crystal is immerged into the solution for crystal growth at a temperature of 3 to 5 DEG C above the saturation temperature of the solution for crystal growth; (2) the temperature of the solution for crystal growth is reduced to the saturation point, afterwards, the crystal grows for 5 to 7 days with a cooling rate of 0.5 DEC C each day, and a little crystal with regular shape is fabricated, then the little crystal is up-lifted for 2 to 4 millimeters without leaving the surface of the solution for crystal growth; (3) the little crystal with regular shape obtained in step (2) is immerged into the solution for crystal growth again as a seed crystal for a new growth until a crystal accorded with the requirement is fabricated; (4) the crystal is lifted off the surface of the solution after the fabrication is finished, the temperature is reduced at the rate of 4 DEG C each hour. When the temperature reaches 200 DEG C, the crystal is cooled to room temperature by natural. The top seed reentry technique has the advantages of simple preparation process, short fabrication cycle, and good stability, and the crystal grown has small seed crystal recovery area and high optical quality.

The invention relates to non-linear optical crystal calcium sodium borate and a preparation method and application thereof. The optical crystal calcium sodium borate is a single crystal with a centimeter dimension and belongs to an orthorhombic system, wherein the molecular formula of the optical crystal calcium sodium borate is NaCa4B3O9, the molecular weight is 359.73, and the unit cell parameters are shown as follows: a is equal to 10.68004(11)A, b is equal to 11.28574(11)A and c is equal to 6.48521(6)A. In the preparation method, a target product is formed by taking calcium sodium borate polycrystal powder and the like as a raw material and by utilizing a flux growth method. In the non-linear optical crystal calcium sodium borate and the preparation method and the application thereof, the raw material has a broad source and is cheap and available. Moreover, the preparation process is simple and is easy to operate and has a short period; an obtained product has the centimeter dimension; inclusions are few; the non-linear optical effect of the non-linear optical crystal calcium sodium borate is approximately equal to 2 / 3 of the non-linear optical effect of potassium dihydrogen phosphate (KDP) to be tested under the same condition; the laser-induced damage threshold is larger; the mechanical property is good; the non-linear optical crystal calcium sodium borate is not easy to fracture and is not deliquescent; the physical and chemical properties are stable; the light transmission band is 220nm to 3000nm; and the non-linear optical crystal calcium sodium borate has a wider light transmission range in ultraviolet and deep ultraviolet areas, is easy to process and store and is suitable for widely being applied in non-linear optical devices, such as ultraviolet frequency doubling generators, upper or lower frequency converters or optical parameter oscillators and the like.

The invention provides a praseodymium-doped lutetium potassium tungstate laser crystal and a preparation method thereof. The crystal belongs to a monoclinic system, a space group is C2 / m, cell parameters are that beta is equal to 130.68 degrees, Z is equal to 4 and Dc is equal to 4.63g / cm<3>. The crystal can be grown by adopting a flux growth method. Large absorption is shown at 451nm in an absorption spectrum of the crystal, absorption cross section reaches 74.4*10<-20>cm<2>, and absorption half-peak width reaches 8nm. The crystal has strong emission in visible light wave band and near infrared wave band, emission cross section at 1073nm reaches 24.3*10<-20>cm<2>, the crystal is expected to become a new laser crystal, and practical application can be obtained.

The invention relates to a (Yb<3+>: LaMgB5O10) doped laser crystal and a growth method thereof. The crystal belongs to a monoclinic system and a P21 / c space group; cell parameters are shown in the specification, wherein Z=4, and Dc=3.92 g / cm<3>. The crystal can be grown by using a flux growth method; by taking Li2O-B2O3-LiF as a mixed flux, under the conditions that the growth temperature is 900-980 DEG C, the cooling rate is 0.5-3 DEG C / day and the rotating speed is 5-30 r / min, a Yb3<+>: LaMgB5O10 single crystal with a high quality and a relatively large size is grown. The crystal shows relatively broad absorption and emission spectrums. The crystal can become a new ultra-short pulse laser crystal, and can be practically applied.

The invention provides an ytterbium-doped molybdic acid gadolinium barium potassium laser crystal and a preparation method thereof. The laser crystal belongs to monoclinic systems, the space group is C2 / m, the cell parameters are as follows: a equal to 17.401 (11) ., b equal to 12.226 (8) ., c equals to 5.324(4) ., Beta equals to 106.19 (1) degree, V equals to 1087.73(373) .<3>, Z equals to 4, and D equals to 4.967 g.cm<3>. The crystal is grown by adopting the flux growth method. The crystal indicates a wider absorption spectrum band and an emission spectrum band. The absorption section of the absorption spectrum band at the 976 nm position is 1.69*10<-20> cm<2>, and the absorption half-peak width is 60 nm. The emission section at the position of about 1010 nm is larger than 3*10<-20> cm<2>. The crystal can become a novel ultrashort pulse laser crystal and can be applied practically.

The invention relates to a BaCa4Se7 compound, a BaCa4Se7 nonlinear optical crystal, a preparation method and application. The BaCa4Se7 compound is prepared by adopting a solid-phase reaction, and the BaCa4Se7 nonlinear optical crystal is grown by adopting a high-temperature melt spontaneous crystallization method, a flux growth method or a Bridgman method. In the growth of the BaCa4Se7 nonlinear optical crystal, the crystal is easy to grow and transparent and has no package and the advantages of higher growing speed, low cost, easy obtaining of a crystal in a larger size, and the like. The obtained BaCa4Se7 nonlinear optical crystal has the advantages of wider optical transparency range, larger hardness, good mechanical property, difficult cracking and deliquescence, easy processing and storage, and the like. The BaCa4Se7 nonlinear optical crystal can be used for preparing a nonlinear optical device.

The invention discloses a nonlinear optical crystal material Sr3Y3BiB4O15 and a preparation method and application thereof. The crystal material is bismuth yttrium strontium borate shown as the chemical formula of Sr3Y3BiB4O15, belongs to a hexagonal system, and has the space group of P63 and the unit cell parameters of a=10.6975(13)A and c=6.7222(12)A. A crystal structure comprises BO3 radicals which are arranged in accordant direction and a BiO3 radical with lone pair electrons which are arranged in accordant direction, so that nonlinear effect is 3 to 5 times that of KH2PO4. A crystal has moderate hardness, is free from being deliquesced or cleaved, and is easy to cut, polish and store. The crystal grows by a flux growth method. The preparation method comprises the following steps of: mixing bismuth yttrium strontium borate and a fluxing agent; heating the mixture to obtain solution; stirring; preserving heat; cooling until the temperature is 0.5 to 3 DEG C above a saturation point; adding crystal seeds; controlling an appropriate temperature lowering speed; when the crystal grows to a certain degree, extracting the crystal out of a liquid surface; and slowly lowering the temperature to room temperature so as to obtain Sr3Y3BiB4O15 monocrystal. The crystal can serve as a frequency doubling crystal in an optical parametric oscillator and a harmonic generator. Moreover, the crystal comprises a yttrium element, so that other rare earth ions can be doped so as to obtain a self-frequency-doubling laser crystal.

The invention relates to a preparation method of strontium fluoroborate nonlinear optical crystals, and applications of the strontium fluoroborate nonlinear optical crystals. Compound synthesis is realized via solid phase reaction, and crystal growth is realized via flux growth method. The preparation method is simple in operation, and low in cost. The obtained strontium fluoroborate nonlinear optical crystals will not deliquesce in the air, possesses excellent mechanical properties and stable physico-chemical properties, is unbreakable, is convenient for processing, and is suitable for preparation of nonlinear optical devices. Frequency-doubled effect of the strontium fluoroborate nonlinear optical crystals obtained by the preparation method is three times of that of KDP, and the strontium fluoroborate nonlinear optical crystals can be widely used in nonlinear optical devices such as double frequency converters and optical parametric oscillators.

The invention discloses a method for growing a gallium nitride single crystal with an extremely low dislocation density by a flux process. The method comprises: setting a patterned masking film on a gallium nitride substrate; using the gallium nitride substrate as a seed crystal, and utilizing a liquid phase epitaxy method for growing to obtain a low-dislocation-density gallium nitride single crystal; and performing dislocation selective etching on the low-dislocation-density gallium nitride single crystal, performing landfilling treatment on corrosion regions to obtain a gallium nitride single crystal containing landfills, using the gallium nitride single crystal containing the landfills as a seed crystal, and utilizing a liquid phase epitaxy method for growing to obtain the gallium nitride single crystal with the extremely low dislocation density. Compared with the prior art, the method can obtain the gallium nitride single crystal with the extremely low dislocation density by a two-step method based on a flux method liquid phase epitaxial growth process, the process is simple and easy to operate, the cost is low, and the method can realize large-scale production of the gallium nitride single crystal with the extremely low dislocation density.

The invention discloses a preparation method of a magnesium-doped neodymium-barium-copper-oxygen large seed crystal, which comprises the following steps: preparing Nd1.6Ba2.3Cu3.3Ox precursor powder, pressing a precursor block, carrying out flux growth to obtain an Mg-doped neodymium-barium-copper-oxygen polydomain block, and splitting the seed crystal. The single Nd1.6Ba2.3Cu3.3Ox precursor powder is utilized to successfully prepare the Mg-doped neodymium-barium-copper-oxygen seed crystal, and thus, the method is simple and efficient. Besides, the Mg-doped neodymium-barium-copper-oxygen polydomain block grown by the method contains the large domain region with the size of up to 15mm, and therefore, the next series of large seed crystal with the size of up to 5mm*5mm can be easily split. Compared with the traditionally used small seed crystal, the large seed crystal has higher heat stability and can more easily control the orientation consistency in the induced block growth process.

The invention relates to a method for preparing an originated multi-section yttrium vanadate laser crystal. By utilizing a flux growth method, an undoped yttrium vanadate crystal with a certain thickness is grown at two ends of a rare earth-doped yttrium vanadate laser crystal so as to prepare the multi-section yttrium vanadate laser crystal. The surface adsorption of the prepared undoped crystalor neodymium-doped crystal is less than 2,150ppm / cm, and the crystal can meet the application requirement of high-power lasers.

The present invention discloses visible laser crystals of a Pr3+ ions doped calcium, magnesium, zirconia, gadolinium and gallium garnet with broadband absorption and a melt method for the crystal growth of the garnet. The crystal has a molecular formula of Pr<3delta> Ca<3x>Gd<3(1-x-delta)>Mg<y>Zr<z>Ga<5(1-y-z)>O<12+delta-15x-2.5y+2.5z>, wherein 0 < x + delta < 1, 0 < y + z < 1. By adjusting the crystal components, an absorption bandwidth of Pr3 + ions is broadened, pumping efficiency within crystal visible band is improved. By adopting traditional crystal pulling method, crucible descent method, flux growth method and other melt method to carry out directional or non-directional crystal growth, the obtained crystals can be used as working substances for all solid state lasers. The present invention has broad application prospects in areas of laser display, laser communication, information storage and the like.

The invention discloses a preparation method of a magnesium-doped neodymium-barium-copper-oxygen large seed crystal, which comprises the following steps: preparing Nd1.6Ba2.3Cu3.3Ox precursor powder, pressing a precursor block, carrying out flux growth to obtain an Mg-doped neodymium-barium-copper-oxygen polydomain block, and splitting the seed crystal. The single Nd1.6Ba2.3Cu3.3Ox precursor powder is utilized to successfully prepare the Mg-doped neodymium-barium-copper-oxygen seed crystal, and thus, the method is simple and efficient. Besides, the Mg-doped neodymium-barium-copper-oxygen polydomain block grown by the method contains the large domain region with the size of up to 15mm, and therefore, the next series of large seed crystal with the size of up to 5mm*5mm can be easily split. Compared with the traditionally used small seed crystal, the large seed crystal has higher heat stability and can more easily control the orientation consistency in the induced block growth process.