μ+-Knight shift study in CdMgx (x = 1%, 2%, 2.5%)

In continuation of our earlier studies of the anomalous temperature dependence of the μ+ Knight shift Kμ in Cd, CdMg (1.2 at %) and CdMg (3.38 at %) - interpreted as due to Van Hope-type singularities in the local density of electron states /1/ - we have studied the temperature dependence of the μ+ Knight shift in polycrystalline CdMg (1.04 at %, 2.05 at %) and in a single crystal of CdMg (2.5 at %). In contrast to pure Cd no anisotropies in Kμ could be detected. The temperature dependence of Kμ in a CdMg (2.05 at %) sample and in the monocrystalline CdMg (2.5 at %) sample essentially reproduces the one previously observed in polycrystalline CdMg (3.38 at %), showing a steplike discontinuity and a logarithmic singularity. A complete different behaviour is observed in CdMg (1.04 at %), where no logarithmic singularity seems to show up and where a steplike discontinuity of opposite sign at around 90 K is clearly seen. If these singularities are still to be interpreted in terms of Van Hove singularities, the question arises why there is such a nonlinear dependence on the Mg concentration. (orig.)