Single crystals of ferroelectric lithium niobate–tantalate LiNb1–xTaxO3 solid solutions for high‐temperature sensor and actuator applications

• Published in: Acta crystallographica. Section B, Structural science Vol. 76; no. 6; pp. 1071 - 1076
• Main Authors: Roshchupkin, Dmitry, Emelin, Evgenii, Plotitcyna, Olga, Rashid, Fahrtdinov, Irzhak, Dmitry, Karandashev, Vasilii, Orlova, Tatiana, Targonskaya, Natalya, Sakharov, Sergey, Mololkin, Anatolii, Redkin, Boris, Fritze, Holger, Suhak, Yuri, Kovalev, Dmitry, Vadilonga, Simone, Ortega, Luc, Leitenberger, Wolfram
• Format: Journal Article
• Language: English
• Published: Malden Blackwell Publishing Ltd 01.12.2020
• Subjects: Acoustic microscopy; Actuators; Atomic properties; Calorimetry; Composition; Crystal growth; Crystals; Curie temperature; Czochralski method; Differential scanning calorimetry; Ferroelectric materials; Ferroelectricity; Inductively coupled plasma; Lithium; Lithium niobates; Mass spectrometry; Phase diagrams; Single crystals; Solid phases; Solid solutions; Surface acoustic waves; Tantalum; Temperature sensors; Unit cell; Wave diffraction; X-ray diffraction
• ISSN: 2052-5192; 2052-5206
• DOI: 10.1107/S2052520620014390

Ferroelectric LiNb1–xTaxO3 solid solutions with various Nb/Ta ratio were grown from the melt by the Czochralski method. The exact composition of the grown crystals was determined by inductively coupled plasma atomic mass spectrometry. The dependence of the crystal composition on the composition of the initial melt was obtained and explained by a wide separation between the phase boundaries of the liquid and solid phases on the LiNbO3–LiTaO3 phase diagram. Using high‐resolution X‐ray diffraction, the parameters a and c of a crystal unit cell were determined (LiNb0.88Ta0.12O3: a = 5.1574 Å and c = 13.8498 Å). Further, the Curie temperature TC of the crystals was measured using the differential scanning calorimetry technique. TC was found to depend on the composition of the crystals that allowed conditions for the monodomainization of the grown crystals to be defined (LiNb0.88Ta0.12O3: TC = 1102°C; LiNb0.33Ta0.67O3: TC = 794°C). Finally, the velocity of surface acoustic waves was determined by scanning electron microscopy and X‐ray diffraction techniques (YZ‐cut of a LiNb0.88Ta0.12O3 crystal: V = 3440 m s−1).