Coexistence of ferromagnetism and superconductivity in NiBi-binary alloy

We investigate the effects of the antiferromagnetic exchange coupling between the Nickel and Bismuth2 atoms (J(int2) < 0) on the magnetizations of the NiBi-binary alloy versus temperature and external magnetic field by means of the effective field theory. We find that the magnetization of the Ni, Bil, Bi2 and total NiBi-binary alloy has two different magnetic phase transitions for the J(int2) < 0. One of them is a first-order phase transition (FOPT) at T-t = 0.349 and the other is a second-order phase transition (SOPT) at T-c = 0.791. We also study the hysteresis behaviors and we find that the values of the coercive field points of the Bi2 are higher than those of the Ni and Bil. Moreover, Ni, Bil and Bi2 components have ferromagnetic hysteresis behaviors whereas the total NiBi has type II superconducting behavior. Therefore, we suggest that ferromagnetism and superconductivity coexist in the NiBi-binary alloy that is qualitatively good agreement with the some experimental and theoretical works.