Textured multilayered piezoelectric structures for energy conversion. (23rd December 2019)

• Record Type: Journal Article
• Authors: Haugen, Astri Bjørnetun; Ringgaard, Erling; Levassort, Franck
• Is Part Of: JPhys energy. Volume 2:Number 1(2020)
• Publication Date: 2019-12-23
• Subjects: piezoelectricity -- texture -- ceramics -- energy harvester -- ultrasound; Power resources -- Research -- Periodicals; Power resources -- Periodicals; 333.79
• DOI: 10.1088/2515-7655/ab5f30
• Languages: English
• ISSNs: 2515-7655

Abstract

Abstract: Piezoelectric materials are essential for the conversion between mechanical and electrical energy, for example in ultrasound imaging and vibrational energy harvesting. Here, we are making and exploring the effects of a new design: co-sintered multilayers with texture (grains of a preferential crystallographic direction). The motivation is the combination of increased piezoelectric response in certain crystallographic directions; multilayer structures where thick films rather than bulk materials can allow higher frequency operation and large area; and co-sintering to avoid detrimental effects from gluing layers together. Samples of the lead-free piezoelectric material Li0.06 (K0.52 Na0.48 )0.94 Nb0.71 Ta0.29 O3 with 0.25 mol% Mn (KNNLTM) were made by tape casting and co-sintering. NaNbO3 platelets with (100) orientation which were used as templates to introduce texture, and polymethyl methacrylate (PMMA) was used as a pore forming agent for making porous substrates. The electrical impedances of the co-sintered samples were recorded and analyzed by equivalent electrical circuit modelling. A texture up to 85% in the [100] crystallographic direction was obtained. The samples displayed ferro- and piezoelectricity, with a maximum thickness coupling coefficient (kt = 0.18) between mechanical and electrical energy in the most textured sample. This demonstrates that the introduction of texture in multilayered, co-sintered piezoelectrics shows promise for improving devices for ultrasound imaging or energy harvesting.