Investigation of the strain-sensitive superconducting transition of BaFe_(1.8)Co_(0.2)As_2 thin films utilizing piezoelectric substrates

摘要

The preparation of biaxially textured BaFe_(1.8)Co_(0.2)As_2 thin films has been optimized on MgO single crystals and transfered to piezoelectric (001) Pb(Mg_(1/3)Nb_(2/3))_(0.72)Ti_(0.28)O_3 substrates. By utilizing the inverse piezoelectric effect the lattice parameter of these substrates can be controlled applying an electric field, leading to a induction of biaxial strain into the superconducting layer. High electric fields were used to achieve a total strain of up to 0.05% at low temperatures. A sharpening of the resistive transition and a shift of about 0.6 K to higher temperatures was found at a compressive strain of 0.035%.