Investigation of Electromechanical Properties and Related Temperature Characteristics in Domain-Engineered Tetragonal Pb(In 1/2 Nb 1/2 ) O 3 –Pb(Mg 1/3 Nb 2/3 )O 3 –PbTiO 3 Crystals Fei Li, z,y Shujun Zhang, w,y Zhuo Xu, z Xiaoyong Wei, z Jun Luo, z and Thomas R. Shrout y z Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education, Xi’an Jiaotong University, Xi’an 710049, China y Materials Research Institute, Pennsylvania State University, University Park, Pennsylvania 16802 z TRS Technologies Inc., State College, Pennsylvania 16801 The orientation-dependent electromechanical properties were calculated for tetragonal Pb(In 1/2 Nb 1/2 )O 3 –Pb(Mg 1/3 Nb 2/3 )O 3 – PbTiO 3 (PIN–PMN–PT) crystals based on single-domain data. The maximum electromechanical coupling k  33 was found to lie along the polar direction [001], whereas the maximum piezo- electric coefficient d  33 was found to occur along [011]. Subse- quently, the piezoelectric properties of [011] poled tetragonal PIN–PMN–PT crystals, with an engineered domain configura- tion (‘‘2T’’), were studied using resonance impedance measure- ment and strain versus electric field (S–E) behavior, where the piezoelectric coefficient d 33 and coupling k 33 of [011] poled crys- tals were found to be on the order of 1000 pC/N and 0.75, respectively. The high d 33 of [011] poled crystals was associated with the high shear coefficient d 15 (B2300 pC/N) in single domain state. Finally, the piezoelectric and electromec- hanical properties of [011] domain engineered tetragonal PIN–PMN–PT crystals were investigated as a function of temperature. In contrast to [001] single-domain PIN–PMN– PT crystals, the piezoelectric coefficient d 33 and coupling k 33 of [011] poled crystals were found to decrease with increasing temperature. I. Introduction R ELAXOR-based ferroelectric single crystals, such as Pb(Mg 1/3 Nb 2/3 )O 3 –PbTiO 3 (PMN–PT) and Pb(Zn 1/3 Nb 2/3 )O 3 – PbTiO 3 (PZN–PT), have been extensively studied because of their ultra-high piezoelectric (d 33 41500 pC/N) and electrome- chanical properties (k 33 40.9). 1,2 The ultra-high piezoelectric re- sponse in relaxor-based rhombohedral crystals with a ‘‘4R’’ engineered domain configuration, has been attributed to the polarization rotation reported by Fu and Cohen, 3 using first principle calculations. The usage temperature range of relaxor- PT-based crystals, however, is limited by their relatively low fer- roelectric–ferroelectric phase transition T R–T s(o1001C), which occurs at significantly lower temperatures than their respective Curie temperatures, due to strongly curved morphotropic phase boundarys (MPB). 4 Thus, extensive studies have been carried out in an attempt to increase T c /T R–T . The ternary crystal system Pb(In 1/2 Nb 1/2 )O 3 –Pb(Mg 1/3 Nb 2/3 )O 3 –PbTiO 3 (PIN–PMN–PT) has been found to be a promising candidate, with compositions exhibiting T R–T s41201C, 5–7 301C higher than the phase-transi- tion temperature of commercial binary PMN–PT crystals. To further broaden the usage temperature range of relaxor- PT-based crystals, another approach is to utilize crystals with the tetragonal phase, where no ferroelectric–ferroelectric phase transition occurs before T c and above room temperature. For the case of PIN–PMN–PT crystals, T c is on the order of 2201C. Recently, a single-domain state was readily realized in [001] poled tetragonal PIN–PMN–PT crystals, with a relatively high electromechanical coupling k 33 , being 0.84, maintaining this value to T c . 8 Following the concept of domain engineering in rhombohedral crystals to achieve higher piezoelectric properties, it was proposed to investigate domain engineering in tetragonal PIN–PMN–PT crystals. Based on the full set of material constants for single-domain tetragonal PIN–PMN–PT crystals, 8 the orientation dependence of the dielectric permittivity e  33 =e 0 , piezoelectric coefficient d  33 , and electromechanical coupling k  33 were calculated for tetrag- onal PIN–PMN–PT crystals at room temperature. The piezo- electric properties of [011] poled tetragonal crystals, with an engineered domain configuration (‘‘2T’’), were studied as a func- tion of electric field and temperature and compared with single domain values. II. Experimental Procedure Tetragonal PIN–PMN–PT single crystals were grown by the modified Bridgman technique. Details of the growth and prop- erties of tetragonal PIN–PMN–PT crystals have been described in Li et al. 8 . The orientation dependence of the dielectric per- mittivity e  33 =e 0 , piezoelectric coefficient d  33 , and electromechan- ical coupling factor k  33 were calculated using the coordinate transformation method described in Nye and colleagues 9,10 The PIN–PMN–PT crystals were oriented along crystallographic [001] and [011] directions by real-time Laue X-ray. The samples were electroded using sputtered gold thin film. The samples were poled using a dc field of 10 kV/cm at 1201C for 5 min, and sub- sequently field cooled to room temperature to avoid cracking. The resonance and antiresonance frequencies of longitudinal vi- bration mode for [011] and [001] poled tetragonal PIN–PMN– PT crystals were determined using an HP4194A impedance analyzer (Palo Alto, CA). The electromechanical coupling factors (k 33 ) and piezoelectric coefficients (d 33 ) were calculated following the IEEE standard. 11 The electric-field-induced strain measurements were carried out using a linear variable differen- tial transducer (LVDT) driven by a lock-in amplifier (Mode SR830, Stanford Research System, Sunnyale, CA). The temper- ature dependence of the dielectric permittivity was determined from the capacitance using a multifrequency LCR meter (HP4284A), which was connected to a computer-controlled high-temperature furnace. The temperature dependence of the D. Damjanovic—contributing editor The work was supported by NIH under Grant No. P41-EB21820 and ONR. w Author to whom correspondence should be addressed. e-mail: soz1@psu.edu Manuscript No. 27367. Received January 11, 2010; approved February 24, 2010. J ournal J. Am. Ceram. Soc., 93 [9] 2731–2734 (2010) DOI: 10.1111/j.1551-2916.2010.03760.x r 2010 The American Ceramic Society 2731