Structural and functional modifications induced by X-ray nanopatterning in Bi-2212 single crystals

We have investigated the modifications induced in the high-Tc superconductor Bi2Sr2CaCu2O8+δ (Bi-2212) by X-ray nanopatterning, which is an innovative, photoresist-free, direct-writing approach recently used to fabricate proof-of-concept electrical devices [Truccato et al., Nano Lett. 2016, 16, 1669]. By means of combined synchrotron microdiffraction and electrical transport measurements carried out on the same Bi-2212 microcrystal, we show that hard X-ray irradiation with fluences of the order of 1012 J/m2, corresponding to doses of the order of 1013 Gy, induces crystal fragmentation into multiple subdomains and decreases the carrier density of the system. We ascertain that the synergistic action of grain boundaries and of oxygen removal from the material dramatically changes the properties of Bi-2212 both in the normal and in the superconducting state. This special feature of X-ray nanopatterning introduces an opportunity that could be exploited to finely tune material structural defects according to the desired properties.