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US 2003/0164137 A1Published application
Hybrid stockbarger zone-leveling melting method for directed crystallization and growth of single crystals of lead magnesium niobate-lead titanate (PMN-PT) solid solutions and related piezocrystals
AssigneeH.C. Materials Corporation
InventorPengdi Han
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Abstract
This invention provides a hybrid Stockbarger zone-leveling melting method for seeded crystallization and the manufacture of homogenous large-sized crystals of lead magnesium niobate-lead titanate (PMN-PT) based solid solutions and related piezocrystals. The invention provides three temperature zones resulting in increased compositional homogeneity and speed of crystal growth, in a cost effective multi-crucible configuration.
Claims31
A crystal growth system, comprising:
- at least one vertical furnace;
- at least one means for inputting thermal energy in said vertical furnace;
- at least a first thermal boundary member adjacent a top side of said thermal in-put means;
- at least a second thermal boundary member adjacent a bottom side of said thermal in-put means;
- and
- said at least first and second thermal boundary members effective to divide said vertical furnace into at least one narrow high-temperature zone, at least one upper low-temperature zone, and at least one lower low-temperature zone during a use of said vertical furnace, whereby each said low-temperature zone has a lower temperature than said high-temperature zone.
3 more elements
A crystal growth system, comprising:
- a triple-zone temperature chamber co-axially containing a crucible assembly having at least three growth sections separated from said temperature chamber by at least two baffles and having sufficient separation therefrom to allow movement there-through during a use;
- at least one high temperature heating elements;
- and
- a means for controllably moving said crucible assembly within said triple-zone chamber during said use.
1 more element
A method of forming a crystalline based material, comprising the steps of:
- providing a precursor material;
- loading at least said precursor material into at least one crucible;
- placing said now-loaded crucible into a rigid ceramic member;
- filling a space formed between said crucible and said ceramic member with at least one powdered ceramic and forming a crucible assembly;
- providing a vertical furnace assembly containing at least a narrow high-temperature zone, an upper low-temperature zone, and a lower low-temperature zone, wherein said low-temperature zones are adjacent respective thermal boundaries and each have a negative thermal gradient vertically bounding said high-temperature zone;
- inserting each said crucible assembly into said furnace assembly and positioning each said crucible assembly on a means for positioning said crucible relative to said high-temperature zone;
- providing a means for controlling of said crucible assembly, said furnace assembly, and said means for positioning;
- operating said furnace assembly and forming an as-grown crystalline material in said crucible at a rate from 0.2 to 2.5 mm/hr;
- and
- maintaining a temperature gradient at a growth interface in said crucible adjacent said high-temperature zone of from 10° C./cm to about 40° C./cm during said step of operating to form said crystalline material.
7 more elements
A PMN-PT based material, comprising:
- a single crystal;
- and
- said single crystal having a formula:
- (1−y)Pb(Mg⅓Nb⅔)1−xTixO3+yPb(R½Nb½)O3 (IX)
- wherein x is defined as molar % 0.00 to 0.50, y is defined as molar % 0.00 to 0.25, and R is selected from Sc, Yb, Sb, In, Co, Lu, and TM.
2 more elements
Dependencies are inferred from the claim text.