Browsing NTNU Open by Author "Haugen, Astri Bjørnetun"

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    • Effect of crystallographic orientation in textured Baa0.92Ca0.08TiO3 piezoelectric materials 

      Haugen, Astri Bjørnetun; Morozov, Maxim; Johnsson, Mats; Grande, Tor; Einarsrud, Mari-Ann (Journal article; Peer reviewed, 2014)
      Strongly textured lead-free Ba0.92Ca0.08TiO3 piezoelectric ceramics were fabricated by tape casting and templated grain growth. Dense ceramics with both favorable and unfavorable texture were successfully prepared. Enhanced ...

    • Piezoelectric K0.5Na0.5NbO3 Ceramics Textured Using Needlelike K0.5Na0.5NbO3 Templates 

      Haugen, Astri Bjørnetun; Olsen, Gerhard Henning; Madaro, Francesco; Morozov, Maxim; Tutuncu, Goknur; Jones, Jacob L.; Grande, Tor; Einarsrud, Mari-Ann (Journal article; Peer reviewed, 2014)
      Improved performance by texturing has become attractive in the field of lead-free ferroelectrics, but the effect depends heavily on the degree of texture, type of preferred orientation, and whether the material is a rotator ...

    • Rayleigh analysis of dielectric properties in textured K0.5Na0.5NbO3 ceramics 

      Haugen, Astri Bjørnetun; Morozov, Maxim; Jones, Jacob L.; Einarsrud, Mari-Ann (Journal article; Peer reviewed, 2014)
      Grain texturing is a known method of exploiting the intrinsic dielectric and piezoelectric anisotropy in ferroelectric ceramics. However, the role of crystallographic texture on anisotropic extrinsic contributions including ...

    • Sintering of sub-micron K0.5Na0.5NbO3 powders fabricated by spray pyrolysis 

      Haugen, Astri Bjørnetun; Madaro, Francesco; Bjørkeng, Lars Petter; Grande, Tor; Einarsrud, Mari-Ann (Journal article; Peer reviewed, 2015)
      K0.5Na0.5NbO3 (KNN)-based ceramics are promising lead-free piezoelectrics, but processing of these materials is an ongoing challenge. Here, we present a spray pyrolysis route to highquality KNN-based powders. Fine-grained ...

    • Structure and phase transitions in 0.5(Ba0.7Ca0.3TiO3)-0.5(BaZr0.2Ti0.8O3) from -100 degrees C to 150 degrees C 

      Haugen, Astri Bjørnetun; Forrester, Jennifer S.; Damjanovic, Dragan; Li, Binzhi; Bowman, Keith J.; Jones, Jacob L. (Journal article; Peer reviewed, 2013)
      The solid solution of (x)Ba0.7Ca0.3TiO3-(1-x)BaZr0.2Ti0.8O3 is known to exhibit high piezoelectric constants. Discrepancies in the reported phase transitions and structure around room temperature, however, have complicated ...

    • Synthesis and characterisation of textured lead-free piezoelectric ceramics 

      Haugen, Astri Bjørnetun (Doktoravhandlinger ved NTNU, 1503-8181; 2014:139, Doctoral thesis, 2014)
      Lead-based piezoelectric ceramics are applied extensively in electromechanical devices. While lead-free alternatives are available, their performance and/or reliability have not yet been developed to the extent that they ...

    • Texturing of lead free piezoelectric ceramics 

      Brennhaugen, Dehlia Eide (Master thesis, 2013)
      Texturing of the lead-free system Ba0.92Ca0.08TiO3 (BCT) was investigated focusing on density, degree of texture and piezoelectric response. BCT templates were prepared in a two-step molten salt synthesis to achieve the ...