No abstract

Magnetic excitations in the itinerant antiferromagnets Mn3Si and Fe-doped Mn3Si have been measured at low temperatures by inelastic scattering of neutrons. Mn3Si is an incommensurate antiferromagnetic with magnetic Bragg points of the form (h, k, l)+(6,6, 6) with 5=0.425. Fe-doped Mn3Si is a commensurate antiferrornagnet with 5= -, '. Its low-energy magnetic excitations have a linear 0 dispersion relation with a slope of approximately 30 meV A, but above 6 meV, the slope increases so that the "cone" of the dispersion relation becomes a "chimney. " Well-defined excitations have been observed at energies up to 7.5k~T~(15 meV). In pure Mn3Si, a similar dispersion cone exists around 0 each satellite magnetic Bragg point with a slope of approximately 37 meVA. The two dispersion cones from a pair of satellite points intersect at about 5 meV. Above this energy the intensity of the inelastic peaks changes drastically, indicating a strong interaction between the cones. For both phases, the damping is very large and increases almost linearly with energy.

No abstract

No abstract

No abstract