Thermal expansion properties of three-dimensional relaxor ferroelectric single crystals

• Published in: Materials science & engineering. B, Solid-state materials for advanced technology Vol. 299; p. 116995
• Main Authors: Xiong, Ruibin, Liang, Min, Lv, Lingfei, Hou, Zeyuan, Wang, Zujian, Yang, Xiaoming, Su, Rongbing, Liu, Ying, Long, Xifa, He, Chao
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.01.2024
• Subjects: Ferroelectricity; Phase transition; Piezoelectricity; Thermal expansion; Piezoelectricity; Thermal expansion; Ferroelectricity; Phase transition
• ISSN: 0921-5107; 1873-4944
• DOI: 10.1016/j.mseb.2023.116995

The easily cracking behavior of relaxor-PbTiO3 based ferroelectric crystals limit their application. The average thermal expansion coefficients of PMN-PT and PIN-PMN-PT single crystals are 7.77–8.21 × 10−6 K−1 and 6.59–7.79 × 10−6 K−1 between 20–600 °C. The compression of the crystal by the platinum crucible and the abnormal thermal expansion behavior around phase transition temperature during the cooling process are the main cause of crystal cracking. [Display omitted] •The average thermal expansion coefficients of PMN-PT and PIN-PMN-PT single crystals are 7.77–8.21 × 10–6 K−1 and 6.59–6.79 × 10–6 K−1 between 20–600 °C.•The compression of the crystal by the platinum crucible and the abnormal thermal expansion behavior around phase transition temperature during the cooling process are the main cause of crystal cracking. Large-size Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) and Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 (PIN-PMN-PT) single crystals have been successfully produced. Nevertheless, the susceptibility of these crystals to cracking substantially hampers their application. This study investigates the thermal expansion characteristics of PMN-PT and PIN-PMN-PT crystals oriented along the 〈100〉, 〈110〉, and 〈111〉 directions, revealing no significant anisotropy. The average thermal expansion coefficients for the PMN-PT and PIN-PMN-PT crystals range from 7.77 to 8.21 × 10−6 K−1 and from 6.59 to 6.79 × 10−6 K−1, respectively, within the temperature range of 20 to 600 °C. Interestingly, the PMN-PT and PIN-PMN-PT crystals demonstrate unusual thermal expansion behavior around the phase transition temperature. The magnitudes of their thermal expansion coefficients are comparable to those of certain commercial crystals but are lower than that of platinum. The main causes inferred for crystal cracking include the pressure exerted by the platinum crucible and the abnormal thermal expansion behavior around the phase transition temperature.