Light scattering in a dilute antiferromagnet : Fe1−xZnxF2

Publisher Website
Google Scholar
Abstract
Inelastic scattering of light by one‐magnon and magnon‐pair excitations has been studied in the dilute antiferromagnet Fe1−xZnxF2 as a function of the concentration x and of the temperature T. As observed in other disordered systems, the two‐magnon peak moves to lower frequencies and broadens with increasing T at fixed x, or with fixed temperature and increasing zinc concentration. Due to the role of short range order the two‐magnon peak does not disappear above the percolation concentration (xp=0.76) or above the Néel temperature for each particular dilution. The one‐magnon peak shows a behavior with temperature similar to that of the k=0 mode in pure FeF2, i.e., it broadens and falls in frequency with increasing T. However, in the high dilution samples the frequency does not tend to zero at the Néel temperature, indicating that the spin excitations in paramagnetically coupled finite clusters can also produce single particle light scattering. At low temperatures the frequency of the one‐magnon peak decreases with increasing Zn concentration from the value 52.7 cm−1 at x=0 to 33.54 cm−1 at x=0.75, which is essentially the percolation limit.

This publication has 8 references indexed in Scilit: