Perovskite Single Crystal Growth With Staged Heating Rate Control
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Solution Overview
Problem
Existing methods struggle to produce single crystals with a large piezoelectric constant and mechanical quality factor across a wide range of material compositions, limiting their effectiveness in devices requiring high power efficiency.
Innovation Solution
A method involving controlled heat treatment with specific temperature increase rates and compositions, including Ba, Ti, and Zr with controlled Mn content, to facilitate abnormal grain growth and produce single crystals with enhanced piezoelectric properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If only heat treatment temperature is adjusted to cause abnormal grain growth, then single crystal production is achieved for limited material compositions, but the method cannot be applied to a wide range of material compositions
Solution Approach 1:
The patent applies parameter changes by introducing multiple controllable parameters (temperature increase rates in different stages, holding time, atmosphere composition) to the heat treatment process. This allows precise control over abnormal grain growth across diverse material compositions including Pb(Mg3Nb2/3)1-xLaxZr1-yTiyO3, Pb(Zr1-xTix)O3, and Pb1-xLaxZr1-yTiyO3 systems, resolving the contradiction between versatility and precision
Solution Approach 2:
The patent implements dynamics by using a multi-stage temperature increase process with different rates (first rate from room temperature to Curie point, second rate from Curie point to liquid phase start temperature). This dynamic control allows adaptation to various material compositions while maintaining precise single crystal grain growth control, overcoming the limitation of fixed-temperature methods
2Reliability
If abnormal grain growth is achieved with limited material compositions, then single crystal production is possible, but piezoelectric constant and mechanical quality factor remain insufficient for high power efficiency applications
Solution Approach 1:
The patent applies preliminary action by conducting heat treatment in a specific atmosphere (oxygen atmosphere with controlled composition) before final single crystal extraction. This preliminary atmospheric control prepares the material structure to achieve high piezoelectric constant and mechanical quality factor, enabling reliable high-performance single crystals without excessively complicating the overall manufacturing process
Solution Approach 2:
The patent utilizes composite materials by incorporating multiple dopant elements (La, Zr, Ti, Mn) in controlled amounts into the base ceramic composition. This composite approach enhances both piezoelectric constant and mechanical quality factor, achieving reliable high-performance single crystals while maintaining reasonable manufacturing complexity through systematic composition design
3Manufacturing precision
If heat treatment is performed without controlled temperature increase rates, then processing is simpler, but abnormal grain growth cannot be reliably caused in materials with difficult compositions
Solution Approach 1:
The patent applies segmentation by dividing the temperature increase process into distinct stages with different rates: first stage from room temperature to Curie point, second stage from Curie point to liquid phase start temperature, and holding stage at liquid phase end temperature. This segmented approach achieves reliable abnormal grain growth in difficult compositions while keeping temperature control complexity manageable through clear stage definitions
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method enables the production of single crystals with larger piezoelectric constants and mechanical quality factors, suitable for a broader range of applications including piezoelectric elements, ultrasonic motors, and diagnostic devices.
Implementation Method 1
a solid-state method in which a seed single crystal is joined to a matrix to be subjected to heat treatment to thereby cause abnormal grain growth in which only a single crystal grain grows
Implementation Method 2
a first temperature-increasing step of increasing a temperature of the integrated body from room temperature to a liquid-phase start temperature of the matrix; a second temperature-increasing step of increasing the temperature of the integrated body from the liquid-phase start temperature to a liquid-phase end temperature of the matrix
Data Source
AI summary
Provided is a method of producing a single crystal by heating a matrix, the method including: a first temperature-increasing step of increasing a temperature of the integrated body from room temperature to a liquid-phase start temperature of the matrix; a second temperature-increasing step of increasing the temperature of the integrated body from the liquid-phase start temperature to a liquid-phase end temperature of the matrix; a heating step of heating the integrated body at the liquid-phase end temperature; and a step of obtaining a perovskite-type single crystal from the matrix after the heating. A rate of temperature increase in the second temperature-increasing step is lower than a rate of temperature increase in the first temperature-increasing step.