Background,Motivation and Objective Crystallographically engineered Relaxor-PT single crystals,specifically PMN-PT,offer much higher piezoelectric and electromechanical coupling coefficients(d33 > 1,500 pC/N,k33 > 0.9),when compared to PZT ceramics.The technique that has commonly been studied and used for fabricating PMN-PT single crystals is the Bridgman method.Commercial production of PMN-PT single crystals by the Bridgman method has been successful with good reproducibility.However,the production cost is still high and a compositional gradient is usually present in the produced crystals.And these single crystals have very limited usage range in terms of temperature,electric field,and stress because of their low TC,TRT and EC.To overcome the high production cost and chemical inhomogeneity problem,the solid-state single crystal growth(SSCG) method has been attempted since the late 1990s.The SSCG method has several advantages over the Bridgman growth,in particular for complex systems,in terms of cost-effectiveness,easy control of chemistry,and the chemical uniformity of the product.Despite these ample advantages,however,studies on the fabrication of single crystals by the SSCG method have only been carried out by a few research groups and commercial application of the technique has been very limited.