High Curie point CaBi2Nb2O9 thin films: A potential candidate for lead-free thin-film piezoelectrics

Abstract

CaBi 2 Nb 2 O 9 ͑CBNO͒ thin films deposited on platinum coated silicon substrates by the polymeric precursor method exhibited good structural, dielectric, and piezoelectric characteristics. Capacitance-voltage measurements indicated good ferroelectric polarization switching characteristics. Remanent polarization and drive voltage values were 4.2 C/cm 2 and 1.7 V for a maximum applied voltage of 10 V. The film has a piezoelectric coefficient d 33 equal to 60 pm/ V, current density of 0.7 A/cm 2 , and Curie temperature of 940°C. The polar-axis-oriented CBNO is a promising candidate for use in lead-free high Curie point in ferroelectric and piezoelectric devices.

Enhancing electromechanical properties of CaBi2Nb2O9 thin films grown on Si

“…When E max was increased to 2000 kV/cm, a saturated polarization (P s ) of ~55 μC/cm 2 , a remnant polarization (P r ) of ~13 μC/cm 2 , and a coercive field (E c ) of ~320kV/cm were achieved in the CBNO film grown on Si. The P r value achieved in our CBNO films on Si is about 200% higher than those grown on unbuffered Si substrates (~4.2μC/cm 2 ) [3,20], and ~30% higher as compared with the CBNO film deposited on TiO 2 -buffered Si [9]. The significantly improved P r corresponds to an improved ferroelectricity in our CBNO films, which was a result of the increased amount of electrically active grains via the strain buffering effect provided by the YSZ layer.…”

“…CaBi 2 Nb 2 O 9 (CBNO), as one of the family members of bismuth layer-structured ferroelectrics (BLSFs), has attracted a lot of research interests due to its high Curie temperature (T c~9 43 o C) [1][2][3]. Such a high T c opens up a lot of opportunities for high temperature electromechanical applications [1,4].…”

“…More recent work include those by A. Z. Simǒes et al [3,7,8], who prepared polycrystalline CBNO films on Si by using a polymeric precursor method, and that with a strong polar-axis orientation by Y. Ahn et al [9] via pulsed laser deposition. The reported electrical property data showed substantial yet not decisive improvements.…”

Polarization and piezoelectric properties of grain-oriented ferroelectric Bi5FeTi3O15 ceramics prepared by magnetic-field-assisted electrophoretic deposition method

“…It is recognized that the entire displacement of the perovskite blocks with respects to the Bi 2 O 2 layers induces ferroelectric nature which appears mainly along the a-axis [1]. This Bi-layered structure leads to a high Curie temperature (T C ) [2,3] and a large spontaneous polarization (P s ) along the a-axis [1,[4][5][6]. Additionally, along the c-axis BLSFs with even m number show paraelectricity whereas those with odd m number exhibit ferroelectricity [7,8].…”

Ferroelectric properties of lead-free polycrystalline CaBi2Nb2O9 thin films on glass substrates

“…[13][14][15] Because the CBNO compounds show high Curie temperatures as Bi-layered ferroelectrics, 11 they show great potential for high-temperature device applications. Characteristically, CBNO shows spontaneous polarization along the a-axis orientation at room temperature with an orthorhombic crystal structure (A2 1 am).…”