Synthesis and Mechanism of Ferroelectric Potassium Tantalate Niobate Nanoparticles by the Solvothermal and Hydrothermal Processes

High‐purity KTa 0.3 Nb 0.7 O 3 nanoparticles have been successfully synthesized by hydrothermal and solvothermal methods. The KOH concentration and the solvent composition have significant effects on the final products. The synthesis mechanism was discussed. X‐ray diffraction, scanning electron microscopy, and transmission electron microscopy investigations show that the typical samples solvothermally synthesized are nanosized, well crystallized, and single crystalline. The KTa 0.3 Nb 0.7 O 3 shows a pseudo‐cubic to tetragonal transition with increasing crystallite size. It is believed that supercritical isopropanol plays an important role in synthesizing KTa 0.3 Nb 0.7 O 3 nanoparticles under milder conditions than the hydrothermal route. The present solvothermal method provides a new potential route for synthesizing ferroelectric potassium tantalate niobate material.