Spin Dynamics in Invar (Fe 65 Ni 35 , Fe 3 Pt) and Non Invar (Fe 50 Ni 50 ) Alloys

摘要: Spin dynamics of a disordered Invar alloy Fe 65 Ni 35 , an ordered 3 Pt as well non 50 have been studied by neutron scattering. It has found that both alloys show common anomalous dynamical properties. Well defined magnon groups could be detected up to the Curie temperature. The spin wave stiffness constant D ( T ) varies with temperature )= 0 (1 - C 5/2 ). excitations, however, explain only about half temrerature variation magnetization M for alloys, in spite fact integrated intensity measurements spectra suggest no other excitations take part accounted excitations. magnons dampen significantly increasing was apparent linewidth \(\varGamma (q, T)\) obeying relation T)=(\varGamma _{0}+aT^{\alpha })q^{2}\) α≤1, quit...