Document type:
Zeitschriftenaufsatz
Author(s):
Martínez, J. L.; B̈oni, P.; Shirane, G.
Title:
Spin Dynamics in {{Ni}} near ${T}_{C}$: {{A}} High-Resolution Neutron Scattering Study
Abstract:
We have studied the magnetic cross section in Ni below and above TC using unpolarized and polarized neutron scattering techniques. For temperatures near the Curie temperature (TC=631 K) and for a range of momentum transfer 0.2$<$q$<$0.4 A˚-1 (Brillouin zone width$\simeq$1.54 A˚-1), the spin waves renormalize as expected from extrapolating the results at smaller momentum transfer (q$<$0.2 A˚-1). At TC the spin waves merge into a broad single peak centered at zero-energy transfer, which is well described by a double-Lorentzian scattering function. Our results, below and above TC, agree with the predictions of the dynamic scaling theory in the area of (q,$\omega$) space and the range of temperatures investigated. This is in contrast with recent measurements which reported magnetic excitations at finite energies above TC.
Journal title:
Physical Review B
Year:
1985
Journal volume:
32
Month:
dec
Journal issue:
11
Pages contribution:
7037
Fulltext / DOI: