High-Temperature Spin Dynamics ofCu-Mn Spin-Glasses

Measurements of spin dynamics of $\mathrm{Cu}$-Mn alloys containing between 1 and 7 at.% Mn reveal the phenomenon of exchange narrowing in neutron scattering, the Korringa relaxation mechanism being responsible for the intrinsic broadening of the paramagnetic spectrum, which is well described by a simple Lorentzian in the dilute limit. Additionally, the spin-spin exchange leads to enhance broadening of the spectrum at higher $q\text{'}\mathrm{s}$ and generally to departures from the simple Lorentzian form of the spectral function.