Method of producing a monolithic crystal by top-seeded solution growth from a liquid crystal flux comprising a mixture of solid precursors

Patent metadata

Field	Value
Publication number	US-10047456-B2
Application number	US-201514717970-A
Country	US
Kind code	B2
Filing date	May 20, 2015
Priority date	Nov 4, 2011
Publication date	Aug 14, 2018
Grant date	Aug 14, 2018

Abstract

A monolithic crystal having the atomic formula WnXmYpZr, with at least one dimension greater than about 10 mm. A method for top seed, solution growth of a monolithic crystal, wherein the method includes the steps of: preparing a precursor, forming a seed crystal, and forming the monolithic crystal. Some configurations of the method include the differential control of the crystal flux temperature in a furnace and the rotational frequency of a seed crystal in the crystal flux.

First claim

What is claimed is:

1. A method of producing a monolithic crystal by top-seeded solution growth, comprising:
forming a crystal flux, wherein forming the crystal flux comprises preparing a mixture of solid precursors, wherein the precursors comprise LiH 2 PO 4 , NH 4 H 2 PO 4 and Fe 2 O 3 ;
forming, via spontaneous crystallization, a seed crystal; and
forming a monolithic crystal by inserting the seed crystal into the crystal flux in a temperature-controlled furnace, wherein at least one dimension of the monolithic crystal is at least 10 mm.

2. The method of claim 1 , further comprising:
mechanically reducing the solid precursors; and
analyzing the purity of the solid precursors.

3. The method of claim 1 , wherein heating the precursors comprises maintaining a liquid crystal flux by controlling the temperature of the precursors within a predetermined range of a critical temperature of the precursors.

4. The method of claim 3 , wherein the critical temperature is one of a saturation temperature or a melting temperature of the precursors.

5. The method of claim 1 , further comprising:
forming the seed crystal by lowering a temperature of the crystal flux from a first temperature to a second temperature;
seeding initial crystals;
collecting the initial crystals; and
forming primary seed crystals.

6. The method of claim 5 , wherein cooling the temperature of the crystal flux further comprises controlling the temperature within a predetermined range of a critical temperature of the crystal flux.

7. The method of claim 5 , wherein the seeding comprises
inserting a seed material into the crystal flux; and
forming an initial plurality of crystals by controlling the temperature of the crystal flux within a predetermined range of a critical temperature of the crystal flux; and
wherein the collecting the initial crystals comprises withdrawing the seed material from the crystal flux, wherein the seed material comprises a Group VIII transition metal wire.

8. The method of claim 5 , wherein forming the monolithic crystal further comprises:
seeding the initial crystal into a crystal flux at a temperature within a predetermined range of a critical temperature of the crystal flux;
rotating the initial crystal in the crystal flux to form a primary crystal;
collecting the primary crystal from the crystal flux; and
processing the primary crystal to form a monolithic crystal.

9. The method of claim 8 , wherein forming primary seed crystals further comprises
cutting the initial crystal;
re-seeding the initial crystal into the crystal flux under controlled temperatures;
growing the initial crystal until at least one dimension is at least 5 mm;
withdrawing the initial crystal from the crystal flux; and
subsequent to withdrawal, mechanically or chemically altering the initial crystal.

10. The method of claim 8 , wherein seeding the initial crystal further comprises coupling the initial crystal to a seed material.

11. The method of claim 8 , wherein rotating the initial crystal comprises controlling the rotational frequency of the initial crystal in the crystal flux to control the shape of the primary crystal.

12. The method of claim 8 , wherein processing the primary crystal comprises mechanically or chemically altering the monolithic crystal.

13. The method of claim 1 , wherein controlling the temperature of the furnace further comprises controlling the temperature within a predetermined range of a melting temperature of the crystal or a saturation temperature of the crystal.

14. The method of claim 1 , wherein preparing the mixture of precursors comprises mixing precursors of LiFeP 2 O 7 and LiH 2 PO 4 at a molar ratio of LiFeP 2 O 7 : LiH 2 PO 4 of 1:X, wherein X is from 0.01 mole to about 0.5 mole.

15. The method of claim 1 , wherein preparing the mixture of precursors comprises mixing precursors of LiFeP 2 O 7 and NH 4 H 2 PO 4 at a molar ratio of LiFeP 2 O 7 :NH 4 H 2 PO 4 of 1:Y, wherein Y is from 0.05 mole to about 0.5 mole.

Assignees

• Univ Houston System

Inventors

• Halasyamani P Shiv
• Zhang Weiguo

Classifications

• H01M4/5825

  Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines · CPC title

• C30B29/30

  Niobates; Vanadates; Tantalates · CPC title

• C30B17/00

  Single-crystal growth onto a seed which remains in the melt during growth, e.g. Nacken-Kyropoulos method (C30B15/00 takes precedence) · CPC title

• C30B9/06 Primary

  using as solvent a component of the crystal composition · CPC title

• C30B29/22

  Complex oxides · CPC title