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Reversible shift in the superconducting transition for La1.85Sr0.15CuO4 and BaFe1.8Co0.2As2 using piezoelectric substrates
2010, Trommler, S., Hühne, R., Iida, K., Pahlke, P., Haindl, S., Schultz, L., Holzapfel, B.
The use of piezoelectric substrates enables dynamic observation of the strain-dependent properties of functional materials. Based on studies with La1.85Sr0.15CuO4 (LSCO), we extended this approach to the iron arsenic superconductors represented by BaFe2− xCoxAs2 to investigate strain-driven changes in detail. We demonstrate that epitaxial thin films can be prepared on (001) Pb(Mg1/3Nb2/3)0.72Ti0.28O3 substrates using pulsed laser deposition. The structural and electric properties of grown films were characterized in detail. A reversible shift of the superconducting transition of 0.4 K for LSCO and 0.2 K for BaFe1.8Co0.2As2 was observed on applying biaxial strains of 0.022 and 0.017%, respectively.
Strain-controlled switching kinetics of epitaxial PbZr0.52Ti0.48O3 films
2013, Herklotz, A., Guo, E.-J., Biegalski, M.D., Christen, H.-M., Schultz, L., Dörr, K.
We investigate the effect of biaxial strain on the switching of ferroelectric thin films. The strain state of epitaxial PbZr0.52Ti0.48O3 films is controlled directly and reversibly by the use of piezoelectric Pb(Mg1/3Nb2/3)0.72Ti0.28O3 (001) substrates. At small external electric fields, the films show switching characteristics consistent with a creep-like domain wall motion. In this regime, we find a huge decrease of the switching time under compressive strain. For larger external electric fields, the domain wall motion is in a depinning regime. The effect of compressive strain is more moderate in this region and shows a reduction in the switching kinetics.