Preparation of BaTiO₃-based thick films withc-axis-preferred orientation using screen printing

Abstract

Pb(Zr,Ti)O 3 and related materials have been lauded for their piezoelectric properties, but their toxicity has driven the search for alternative materials with the same high performance in electronic devices. Among these, BaTiO 3 -based materials are regarded as excellent substitutes. Using a screen printing method, in this study, we prepare BaTiO 3 thick films on ZrO 2 stabilized with 3 mol % Y 2 O 3 (YSZ) or MgO ceramics with Pt bottom electrodes. BaTiO 3 thick films prepared on YSZ and MgO substrates preferentially oriented along the a-and c-axes, respectively. The remanent polarization P r of the MgO-based films was higher than that of the YSZ-based films (10.8 µC/cm 2 vs 6.5 µC/cm 2 ) and comparable to that of BaTiO 3 bulk ceramics. Thermal expansion measurements of BaTiO 3 , YSZ, and MgO ceramics suggested that compressive stress was exerted on the BaTiO 3 thick films, causing them to orient along the c-axis. (Ba 0.92 Ca 0.08 )(Ti 0.975 Zr 0.025 )O 3 thick films were also prepared on the YSZ and MgO substrates and showed similar preference for the c-axis on MgO. However, the remanent polarization of (Ba 0.92 Ca 0.08 )(Ti 0.975 Zr 0.025 )O 3 thick films prepared on MgO was greater than that of bulk ceramics (14.9 µC/cm 2 vs 11.0 µC/cm 2 ).

Effect of MnO2 addition on temperature-dependent properties of tetragonal (Bi,Na)TiO3–BaTiO3 thick films prepared on MgO ceramic substrates

“…Under compressive stress, the c-axis in the thick films tends to be perpendicular to the substrate when the phase transition from the cubic to the tetragonal phases occurs. 16,[30][31][32] Therefore, the preferential c-axis orientation of the thick films in Fig. 5 indicates the presence of compressive stress in the thick films.…”

“…The Pb-based materials have been used in many applications such as actuators and sensors. [1][2][3] Possible replacements for Pb-based materials are (Bi,Na)TiO 3 , [4][5][6][7][8][9][10][11] (K,Na)NbO 3 , [12][13][14][15] and BaTiO 3 [16][17][18] and their solid solutions. Among them, (1-x)(Bi,Na)TiO 3 -xBaTiO 3 (BNT-100xBT) and related materials have been studied intensively because of their excellent electrical properties.…”

Preparation of Pb(Mg1/3Nb2/3)TiO3–PbTiO3 thick films with highly preferred orientation via screen printing

“…Screen-printable paste was prepared using the BT powder. 16,17) The BT paste was used to form template layers. A schematic of the preparation process of the thick films is shown in Fig.…”

“…The pseudocubic (pc) notation was used as needed. The 〈100〉 pc orientation degree was evaluated using the Lotgering factor F. 16,32) The c domain volume fraction (V c ) of the tetragonal phase was calculated following the process in a previous study. 31) A V c value of 0.5 indicates that the sample is randomly oriented, such as powders and bulk ceramics.…”

“…However, highly oriented BaTiO 3 -based thick films can be prepared via screen printing. [16][17][18][19] Among the 〈100〉 pc -oriented BaTiO 3 -based thick films, (Ba 0.92 Ca 0.08 )(Ti 0.975 Zr 0.025 )O 3 thick films exhibited approximately 1.4 times more remanent polarization (P r ) value than bulk ceramics. 16) However, the electrical properties of Pbfree piezoelectric films, such as (Ba 0.92 Ca 0.08 )(Ti 0.975 Zr 0.025 )O 3 thick films (although they are oriented), are generally inferior to those of Pb-containing piezoelectric materials.…”