Use of magnetization density fluctuation spectra to estimate the electrical resistivity in YCo2

Key physical properties of the non-magnetic RCo2 compounds (R = Sc, Y and L u) suggest that their behaviour is dominated by spin fluctuations. For exam ple, the enhanced linear term in the heat capacity and the T-2 increase of the resistivity at low temperatures followed by a pronounced saturation of rho against T at ambient temperatures have been taken as evidence for this mechanism. We report the measurement of the dynamical spin fluctuation spec trum in polycrystalline YCo2 (ScCo2) samples by a combination of time-of-fl ight neutron scattering with high energy resolution on the IN5 spectrometer of the Institut Laue-Langevin (ILL) Grenoble with results obtained from th e polarized neutron diffractometer D7 (ILL). The low frequency properties o f the generalized magnetic susceptibility have been modelled by a single im aginary pole: Im[chi(q, omega)] = omega z chi(q)Gamma(q)[omega(2)Gamma(q)(2 )](-1) with the static wavevector dependent susceptibility approximated by chi(q)(-1) = chi(0)(-1) + cq(2). From the resistivity data we have extracte d the spin scattering component and show that it is consistent, using a sim ple model based on the Boltzmann formalism, with Im[chi(q, omega)] as measu red by neutron scattering. In this analysis, the stiffness constant, c, whi ch is found to be temperature dependent, appears critical in modelling the saturation of rho on approaching ambient temperatures.