Magnetic properties of perovskite-type Fe-Ni nitrides gamma '-(Fe1-xNix)(4)N (0 <= x <= 0.9)

In this work, we have succeeded in preparing gamma'-(Fe1-xNix)(4)N powder s amples for x up to 0.9 and have undertaken a systematic study of their stru ctural and magnetic properties by x-ray diffraction and vibrating sample ma gnetometry. The lattice parameters of the nitrides decrease monotonically f rom 0.3795 to 0.3747 nm with increasing Ni concentration. The saturation ma gnetization, measured at room temperature and liquid nitrogen, was found to decrease with increasing Ni concentration. The Curie temperature T-C also decrease with increasing Ni concentration, as well as with decreasing latti ce parameter. Our results show that the lattice parameters, sigma(s) and T- C behave in contrast with those of the corresponding fcc gamma-Fe1-xNix all oys, for which each of these properties exhibits a maximum at some intermed iate composition. (C) 1999 American Institute of Physics. [S0021-8979(99)20 808-0].