Browsing NTNU Open by Author "Tjønneland Wefring, Espen"
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Electrical conductivity and ferroelastic properties of Ti-substituted solid solutions (1-x) BiFeO3 – x Bi0.5K0.5TiO3
Tjønneland Wefring, Espen; Schader, Florian H; Webber, Kyle G; Einarsrud, Mari-Ann; Grande, Tor (Journal article; Peer reviewed, 2016)The high crystallographic strain and polarization of BiFeO3 are attractive, but utilization of bulk BiFeO3 has been hindered by large leakage current and high coercive field. Here, we report on the electrical conductivity ... -
Electrical conductivity and thermopower of (1-x) BiFeO3 - xBi(0.5)K(0.5)TiO(3) (x=0.1, 0.2) ceramics near the ferroelectric to paraelectric phase transition
Tjønneland Wefring, Espen; Einarsrud, Mari-Ann; Grande, Tor (Journal article; Peer reviewed, 2015)Ferroelectric BiFeO3 has attractive properties such as high strain and polarization, but a wide range of applications of bulk BiFeO3 are hindered due to high leakage currents and a high coercive electric field. Here, we ... -
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 ... -
Mechanical stability of piezoelectric properties in ferroelectric perovskites
Schader, Florian H; Morozov, Maxim; Tjønneland Wefring, Espen; Grande, Tor; Webber, Kyle G (Journal article; Peer reviewed, 2015)The influence of uniaxial compressive stress on the small signal direct piezoelectric coefficient of hard and soft Pb(Zr,Ti)O3 at the morphotropic phase boundary was investigated as a function of temperature from 25 °C to ... -
Oxygen permeation in symmetric and asymmetric La0.2Sr0.8Fe0.8Ta0.2O3-d membranes
Gurauskis, Jonas; Lohne, Ørjan Fossmark; Lagergren, Dan Stræte; Tjønneland Wefring, Espen; Wiik, Kjell (Journal article; Peer reviewed, 2016)La0.2Sr0.8Fe0.8Ta0.2O3 − δ (LSFT) is a mixed ionic electronic conductor (MIEC) at elevated temperatures and as such a candidate material for applications both in syn-gas synthesis and as electrodes in solid oxide fuel cells ... -
Solid-State Synthesis and Properties of Relaxor (1 – x)BKT–xBNZ Ceramics
Tjønneland Wefring, Espen; Morozov, Maxim; Einarsrud, Mari-Ann; Grande, Tor (Journal article; Peer reviewed, 2014-07-08)Conventional solid-state synthesis was used to synthesize dense and phase pure ceramics in the (1−x) Bi0.5K0.5TiO3–xBi0.5Na0.5ZrO3 (BKT–BNZ) system. Structural characterization was done using X-ray diffraction at both room ...