Structure-induced coexistence of ferromagnetic and superconducting states of single-phase Bi₃Ni seen via magnetization and resistance measurements

We demonstrate the coexistence of superconductivity and ferromagnetism in Bi₃Ni nanostructures that have been prepared by making use of novel chemical-reaction paths. We have characterized their magnetic and superconducting properties by means of magnetometry and electrical-transport measurements. Other than in bulk geometry, submicrometer-sized particles and quasi-one-dimensional nanoscaled strains of single-phase Bi₃Ni undergo ferromagnetic order. Superconductivity in confined Bi₃Ni emerges in the ferromagnetically ordered phase and is stable up to remarkably high magnetic fields. Uniquely, ferromagnetic hysteresis at zero resistance is observed in nanostructured Bi₃Ni.