Effect of mechanically-applied uniaxial tensile strain on the onset critical temperature of a superconducting bulk Bi2Sr2CaCu2O8+δ

Abstract

We have investigated the effect of uniaxial tensile strain ϵ applied along the in-plane direction on the onset critical temperature of a bulk Bi₂Sr₂CaCu₂O_8+δ (Bi-2212). The applied strain is generated using a mechanical strain device that has a built-in strain measurement system. The sample, tensioned at increasing strains, was cooled down to 5 K using an AC electrical transport measurement system, and we examined the resulting resistance vs. temperature plots. We find that the superconducting transition temperature of the bulk Bi-2212 decreased from 73.99 K with no strain to 73.09 K with 0.18% strain. Straining the bulk sample to 0.30%, the limit of the device, ultimately destroyed the superconductivity, and the result was irreversible even after reducing the strain to 0.24%. These observed effects of the applied uniaxial tensile strain on the T_{c, onset} can be attributed to the formation of microfractures and grain decoupling in the bulk sample.