Giant Electrostrictive Responses and Temperature Insensitive Strain in Barium Titanate‐Based Ceramics

Abstract

property with excellent temperature stability and improved T C in consideration of actual applications. In addition, the electrostrictive effect, serving as a basic electromechanical phenomenon in all insulators or dielectrics, has become a hot topic in the field of lead-free piezoelectric materials. [9][10][11][12] Compared with the piezoelectric effect, the electrostrictive effect has several unique advantages, including little or no hysteretic loss up to high frequencies, superior temperature stability, and a fast response time. [13] Furthermore, electrostriction is a four-rank tensor property, and thus it can be observed in all crystal symmetries. [14] Previously, the best electrostrictive materials are well known as Pb(Mg 1/3 Nb 2/3 )O 3 (PMN) relaxors with a large electrostrictive coefficient Q 33 of 0.02 m 4 C −2 . [15] Recently, some lead-free piezoelectric ceramics with relaxor behavior have exhibited the enhancement of electrostrictive effect due to their hysteresisfree characteristics. [9,11,12] On the other hand, some efforts have been employed to not only improve the electrical properties but also increase the T C of BT-based ceramics by chemical modifications, [16,17] and unfortunately most of the additives deteriorated the T C of BT-based ceramics, such as La, Gd, Sr doping in A-site [18][19][20] or Zr, Sn, Hf doping in B-site. [2,6] Based on above discussions, we want to realize the temperature-insensitive strain and the enhanced electrostrictive effect along with increasing T C by developing the material system of 0.95BaTiO 3 -0.05(M 0.5 N 0.5 )TiO 3 (M = K/Na/Li and N = Ho, Y, Yb, Ga, Nd, Pr, Sm, Gd). A distinguished temperature-insensitive strain behavior from room temperature to 130 °C is achieved in BT-(Li, Ho/Y/Yb)T. In addition, giant electrostrictive coefficient (Q 33 ) of 0.05-0.07 m 4 C −2 , which is twice larger than classical electrostrictive lead-based materials, [15] is observed in BT-(Li, Ho/Y/Yb)T ceramics over a wide temperature region. Meanwhile, inspiringly, an improved T C of 130-145 °C is achieved in BT-(K/Na/Li, Ho/Y)T six samples. A mechanism related to electrostrictive effect has been proposed to explain such an outstanding temperature insensitivity of strain property. It is believed that the giant Q 33 and the good temperature stability of strain would attract potential interest in search of novel leadfree electrostrictive materials.

Multifunctional barium titanate ceramics via chemical modification tuning phase structure

“…For monovalent‐ion substitution such as Li + , Na + , K + , etc., 63‐66 the T C of BT is basically unchanged, while a suppressed dielectric constant at T C can be found. These ions mainly result in the shifting of T R‐O and T O‐T to low temperature and make ferroelectric R‐O and O‐T phase transitions diffusion (Type 1, Figure 2E1), 65,66 implying a certain degree of breaking in long‐range ferroelectric orders but the still remained ferroelectric phase. In addition, adding relatively high‐content Sr 2+ or low‐content trivalent ions (Al 3+ , Bi 3+ , La 3+ , Ce 3+ , Pr 3+ , Nd 3+ , Sm 3+ , etc.)…”

“…Pure BT exhibits strong electrostrictive effect with a high Q 33 of ~0.035 m 4 /C 2 , 124 and its Q 33 can be improved to ~0.04 to 0.055 m 4 /C 2 via chemical modification. If oxygen octahedron space is tuned by A‐sites engineering, Q 33 can soar to ~0.06 to 0.07 m 4 /C 2 66,118,119,122‐129 . The outstanding electrostrictive effect may contribute to the superior electro‐strain property of BT‐based ceramics that is higher than lead‐based and other lead‐free systems.…”

“…A, Comparison of Q 33 for lead‐based ceramics 66,110 and lead‐free systems including SrTiO 3 (ST)‐, 132 BiFeO 3 (BFO)‐, 133 (K, Na)NbO 3 (KNN)‐, 134 (Bi 0.5 Na 0.5 )TiO 3 (BNT)‐, 130,131 NaNbO 3 (NN)‐, 135‐137 and BT‐based ceramics 66,118,119,122‐129 . B, Comparison of room‐temperature strain and hysteresis for lead‐based and lead‐free ceramics 18,19,21,26,29,30,34‐38,41,54,66,68,70,72,83,91,100‐104,110,118‐137 …”

High‐Performance Electrostrictive Relaxors with Dispersive Endotaxial Nanoprecipitations

“…Traditionally, Q 33 is considered to be the main parameter for evaluating the electrostrictive property of a material because of its insensitivity to chemical components, temperature, and the external electric field. [9][10][11] However, because of the difficulty in controlling the polarization, modulating the strain by changing the polarization is a challenging task. In contrast, the strength of the electric field in actuators can be easily controlled, indicating that M 33 is more suitable than Q 33 for characterizing the electrostrictive performance in practice.…”

Morphotropic Relaxor Boundary Construction Highly Boosts the Piezoelectric Properties of Bi-Based Lead-Free Thin Films

“…In the hope of alleviating the environmental and human impact of lead-containing piezoelectric devices, lead-free piezoelectric materials have emerged . At present, there are many candidate materials for lead-free piezoelectric materials, including (Bi 0.5 Na 0.5 )­TiO 3 (BNT), − (K 0.5 Na 0.5 )­NbO 3 (KNN), − BaTiO 3 , , and BiFeO 3 (BFO). , BNT stands at the forefront of lead-free piezoelectric materials because of its high electrostatic strain, strong ferroelectricity, and high Curie temperature ( T c ). , …”