Study of short range order in Fe-Ni-Si-B amorphous alloys

Mossbauer studies on a series of transition metal-metalloid metallic glasse s Fe78-xNixSi8B14, with x = 8, 15, 25, 38, 53, 58 have been done with an ai m to get information about short range order (SRO) in this system. Thermal neutron irradiation up to a dose of 10(19) neutrons/cm(2) has been used to perturb the SRO in the specimens. The effect of neutron irradiation is seen to increase the Curie temperature of the Ni-rich alloys. Further. the aver age number of metalloid near neighbours of Fe increases with increasing Ni concentration, although the metalloid concentration remains unchanged. It i s suggested that also ill amorphous Fe-Ni-B alloys, similar to crystalline Fe-Ni-B alloys, Ni preferentially goes to sites which have less number of B near neighbours, driving the Fe atoms to occupy the sites with larger numb er of B near neighbours. Irradiation partially destroys this preferential s ite occupancy. As observed by earlier workers, sharp variations around 40% Ni concentration in Mossbauer parameters and resistivity may at least partl y be attributed to the preferential site occupancy by Ni. (C) 2001 Elsevier Science B.V. All rights reserved.