The superconductivity of niobium titanium alloy superconductor under ultra high pressure was systematically studied. It is found that niobium titanium alloy still maintains the superconductivity with zero resistance under the pressure of up to 261.7GPa, which indicates that niobium titanium alloy is the most pressure-resistant superconductor known among all superconductors. This pressure is the highest pressure at which superconductivity has been reported. Under this pressure, the transition temperature of niobium and titanium alloy superconductor superconductivity increased from 9.6k to 19.1k at atmospheric pressure, and the results of high-voltage magnetoresistance experiment of strong magnetic field showed that the critical magnetic field increased from 15.4t to 19T at 211GPa pressure and 1.8k temperature. This is the highest superconducting transition temperature and the highest critical magnetic field found in transition metal alloy superconductors. The experimental results showed that the crystal structure did not change under the pressure of 200 GPa, but the volume was compressed by about 43%.
Niobium titanium alloy superconductor has been widely used in thousands of known superconductors with its excellent comprehensive properties. Niobium titanium alloy is a typical binary alloy composed of transition group elements. In the previous study on the high entropy alloy superconductor (TaNb)0.67(HfZrTi)0.33 composed of multi-element transition group metal elements, it was found that under the ultra-high pressure (the pressure above the pressure of one million atmospheres is the ultra-high pressure, the pressure of one million atmospheres =100 GPa), the alloy showed an unusually stable superconductivity. Because niobium and titanium are the main constituent elements of this high entropy alloy, the study on the superconductivity of niobium titanium alloy under ultra-high pressure can deepen the understanding of the microscopic mechanism of the superconductivity of high entropy alloy.
The study reveals the made of the element of transition metal alloy superconductor in high pressure the superconductivity can resist deformation and stability of characteristics, it has to do with copper oxides and iron-based superconductors superconductivity sensitivity to the height of the volume change is in stark contrast, and after the transition metal elements also superconductors (valence electronic d in closed shells) of the superconducting transition temperature drop behavior are obviously different according to the volume compression. This research successfully combined the experiments on large scientific devices such as high pressure extreme conditions, strong magnetic field and synchrotron radiation, and provided a new example for the use of our own large scientific devices to jointly carry out cutting-edge scientific research.
