Piezoelectric properties of layered perovskite A2Ti2O7 (A=La and Nd) single-crystal fibers

Abstract

Lanthanum and neodymium titanate A2Ti2O7 (A=La, Nd) single-crystal fibers were grown via the laser-heated pedestal growth technique. The single-crystal fibers were 600 μm in diameter and 3–4 cm in length. The piezoelectric, k23 and d23, and elastic compliance, s33, coefficients were measured using the standard resonance-antiresonance technique. From a comparison of the measured coefficients to poled single crystal data in the literature, it is concluded that the La2Ti2O7 single-crystal fiber grew in a single domain state.

Study on properties of tantalum-dopedLa2Ti2O7ferroelectric ceramics

“…The highest Curie temperatures have been found in some perovskite-like layer structured (PLS) ferroelectrics with a general formula of A 2 B 2 O 7 , such as La 2 Ti 2 O 7 (T c $ 1461 C), Nd 2 Ti 2 O 7 (T c $ 1482 C), Sr 2 Nb 2 O 7 (T c $ 1327 C), etc. [10][11][12][13][14][15][16][17] Their super-high Curie points has stimulated considerable interests in this system. Among them, La 2 Ti 2 O 7 is a promising candidate for hightemperature piezoelectric sensors due to its piezoelectric activity and extremely high Curie point.…”

“…17 However, polycrystalline ceramics are difficult to be poled because of the low crystal symmetry, which offers few equivalent directions to polarization, and the randomly oriented grains which make the E c of ceramics much higher than those of single crystals. 10,12 18 In lead zirconate titanate (PZT) ceramics, pentavalent donor additions (niobium and tantalum) were reported to produce significant effects on mechanical and electrical properties, characterized by enhanced dielectric constant and dc resistivity and by a well-defined hysteresis loop. 19 This motivated us to study effects of tantalum substitution on the structure, dielectric and piezoelectric properties of La 2 Ti 2 O 7 .…”

Microstructure and local electrical behavior in [(Nd2Ti2O7)4/(SrTiO3)n]10 (n = 4–8) superlattices

“…The third scenario that might explain the higher conductivity in the (NTO 4 /STO 4 ) 10 superlattice is based on polar discontinuity existing across the NTO/STO heterointerfaces. 55 As reported by Herranz et al in the ideal ionic limit, the SrTiO 3 As a result, we assumed that the interfaces between STO and NTO should exhibit polar discontinuity. Furthermore, as reported by Ohtomo et al, 55 polarity discontinuities oen arise in naturally layered oxide structures, such as ferroelectric titanates, including layered-perovskite phases constructed as A n B n O 3n+2 for n ¼ 2-6, and then the concerned Nd 2 Ti 2 O 7 oxide corresponding to n ¼ 4.…”

“…8,9,20 Furthermore, the introduction of insulating STO layers within ferroelectric layers to form articial superlattices has been shown to be promising for modulating the physical properties of thin lms. [21][22][23][24] For example, improved ferroelectric properties have been reported for BaTiO 3 (BTO)/STO superlattices, [25][26][27] while for BiFeO 3 (BFO)/ STO superlattices, a reduced leakage current was observed in the symmetric superlattices.…”

Effects of barium substitution on the sintering behavior, dielectric properties of Ca2Nb2O7ferroelectric ceramics

“…[1][2][3][4][5][6][7][8][9][10] The diverse properties of A n B n O 3nþ2 are related to their unique structure composed of corner-shared BO 6 octahedra with A cations within the perovskite-like layers, where n is the number of octahedral layers in the perovskite slab. 1,2,5 In the PLS structure, A sites can accommodate large cations, e.g., alkali metals, alkalineearth metals, and rare earths metals, and B sites (A and B) are available for a wide variety of small cations with high ionic polarizability, such as Ti, Nb, Ta, W, etc.…”