• The Effect of Thermal History on the Structural and Dielectric Properties of Tetragonal Tungsten Bronzes 

      Aamlid, Solveig Stubmo (Master thesis, 2016)
      Tetragonal tungsten bronzes (TTB) are remarkable materials for their potential for chemical substitution and disorder. The niobates of this kind are usually ferroelectric, and they can comprise both ordered and disordered ...
    • Ferroelectric Transitions in SrxBa(1-x)Nb2O6 - Effect of Thermal History on the Functional Properties 

      Brandvik, Trond (Master thesis, 2015)
      Many functional materials used in todays electronic equipment have a high content lead. Due to the environmental challenges related to production and usage of such materials, extensive research has been preformed on lead-free ...
    • Ferroelectric Tungsten Bronzes 

      Olsen, Gerhard Henning (Doctoral thesis at NTNU;2016:237, Doctoral thesis, 2016)
      Ferroelectric materials are everywhere in the modern society, from consumer electronics to car engines. Applications cover a whole range of devices such as sensors, actuators and transducers due to their dielectric or ...
    • Interstitial oxygen as a source of p-type conductivity in hexagonal manganites 

      Skjærvø, Sandra Helen; Tjønneland Wefring, Espen; Nesdal, Silje K.; Gaukås, Nikolai Helth; Olsen, Gerhard Henning; Glaum, Julia; Tybell, Per Thomas Martin; Selbach, Sverre Magnus (Journal article; Peer reviewed, 2016)
      Hexagonal manganites, h-RMnO3 (R=Sc, Y, Ho–Lu), have been intensively studied for their multiferroic properties, magnetoelectric coupling, topological defects and electrically conducting domain walls. Although point defects ...
    • On the energetics of cation ordering in tungsten-bronze-type oxides 

      Olsen, Gerhard Henning; Selbach, Sverre Magnus; Grande, Tor (Journal article; Peer reviewed, 2015)
      Oxides with the tetragonal tungsten bronze (TTB) structure are well-known ferroelectrics that show a large flexibility both with respect to chemical composition and cation ordering. Two of the simplest compounds in this ...
    • Origin of ferroelectric polarization in tetragonal tungsten-bronze-type oxides 

      Olsen, Gerhard Henning; Aschauer, Ulrich; Spaldin, Nicola A.; Selbach, Sverre Magnus; Grande, Tor (Journal article; Peer reviewed, 2016)
      The origin of ferroelectric polarization in tetragonal tungsten-bronze- (TTB-) type oxide strontium barium niobate (SBN) is investigated using first-principles density functional calculations. We study in particular the ...
    • 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 ...
    • Role of Lone Pair Cations in Ferroelectric Tungsten Bronzes 

      Olsen, Gerhard Henning; Sørby, Magnus Helgerud; Selbach, Sverre Magnus; Grande, Tor (Journal article; Peer reviewed, 2017)
      The role of lone pair cations in tetragonal tungsten bronze (TTB) ferroelectrics has so far not been addressed in detail despite the importance of lone pairs for the polarization mechanism in the prototype ferroelectric ...
    • Texturing of lead-free piezoelectric ceramics 

      Olsen, Gerhard Henning (Master thesis, 2012)
      A procedure for texturing of lead-free piezoelectric ceramics based on sodium potassium niobate (KNN) was investigated with respect to texturing procedure and choice of materials.Material compositions that were considered ...