Magnetic structure of the FeNi invar alloys

Abstract

The magnetic neutron scattering by monocrystals and polycrystals of structuraly distorted FecNi1−c invar alloys is studied. Antiferromagnetic superstructure reflections together with usual ferromagnetic order are found at 4.2 K in the 0.60 < c < 0.68 alloys. The wave vector of the antiferromagnetic structure is (½ + μ, ½ – μ, ν)2π/α. As far as concentration of Fe increases the quantities μ, ν → 0. It is shown that the basic magnetic state of the invar alloys is a noncolinear magnetic structure.

Neutron scattering studies of amorphous invar alloys

“…If the rapid decrease of the magnetization in amorphous Invar alloys is due to longitudinal fluctuations originated by noncollinear magnetic arrangements, as propossed by Continentino and Rivier, one might ask if this mechanism could be extended to the crystalline Invar systems. This would require noncollinear magnetic structures in these crystalline Invar systems, like the one proposed by Dubinin et al [27] for the Fe-Ni Invar. This topic also requires further study.…”