Electronic Resource
[S.l.]
:
American Institute of Physics (AIP)
Journal of Applied Physics
61 (1987), S. 3692-3692
ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
The problem of spin dynamics in disordered magnets has been a subject of research for the past two decades. Diluted systems are of special interest since they exhibit percolation effects for concentrations near the percolation threshold (xp). For concentrations x〉xp the system should look uniform at long wavelengths and highly disordered at short wavelengths; the latter regime should exhibit fractal geometrical characteristics; specifically, as a function of decreasing wavelength, one might expect a crossover from magnon to "fracton'' behavior. A recent high-resolution inelastic neutron scattering study on a large (8 cm3) single crystal of (Mn0.5Zn0.5)F2 shows just these effects. At T=5 K Mn0.5Zn0.5F2 exhibits very sharp spin waves at small q and ω which become rapidly broader with increasing q; further, the excitations are essentially localized in character at higher energies. In this case by "localized'' we mean extremely broad both in energy at fixed wave vector and in wave vector at fixed energy; the crossover from "magnons'' to "fractons'' occurs when the wave vector is comparable to the inverse pair connectedness ξ−1 for the diluted system.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.338663
Permalink
| Library |
Location |
Call Number |
Volume/Issue/Year |
Availability |
