Dynamic variation of biaxial strain in optimally doped and underdoped YBa2Cu3O7-δ thin films

Continuous and reversible biaxial strain was applied to optimally doped and underdoped YBa2Cu3O7-delta (YBCO), using epitaxial thin films on (001)-oriented piezoelectric Pb(Mg1/3Nb2/3)(0.72)Ti0.28O3 substrates. Biaxial strain of up to 0.1% was induced into the YBCO ab-plane by applying an electric field to the substrate, leading to a continuous and reversible shift of the superconducting transition temperature, the normal state resistance and the upper critical field. The shift of the superconducting transition temperature was determined to about 0.75K per 1% compressive biaxial strain for optimally doped YBCO, whereas a significant higher strain sensitivity of 4.20 K per 1% strain was found for underdoped YBCO. These values were compared to strain sensitivity data calculated out of available data from pressure experiments, showing a rather good agreement. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4797493]