Electronic transport evolution across the successive structural transitions in Ni_50-x Fe _x Ti₅₀ shape memory alloys

Abstract TiNi-based shape memory alloys have been extensively investigated owing to their significant applications, but a comprehensive understanding of the evolution of electronic structure and electrical transport in a system with martensitic transformations (MT) is still lacking. In this work, we focused on the electronic transport behaviors of three phases in Ni50-x Fe x Ti50 across the MT. A phase diagram of Ni50-x Fe x Ti50was established based on the x-ray diffraction, calorimetric, magnetic, and electrical measurements. To reveal the driving force of MT, the phonon softening was revealed by using the first-principles calculations. Notably, the transverse and longitudinal transport behavior changed significantly across the phase transition, which can be attributed to the reconstruction of electronic structures. This work promotes the understanding of phase transitions and demonstrates the sensitivity of electron transport to phase transition.