μ+ shift study inCdMgx (x=1%, 2%, 2.5%)shift study inCdMgx (x=1%, 2%, 2.5%)

In continuation of our earlier studies of the anomalous temperature dependence of the μ⁺ Knight shift K_μ in Cd,CdHg (1.2 at %) andCdMg (3.38 at %) — interpreted as due to Van Hove-type singularities in the local density of electron states /1/ — we have studied the temperature dependence of the μ⁺ Knight shift in polycrystallineCdMg (1.04 at %, 2.05 at %) and in a single crystal ofCdMg (2.5 at %). In contrast to pure Cd no anisotropies in K_μ could be detected. The temperature dependence of K_μ in aCdMg (2.05 at %) sample and in the monocrystallineCdMg (2.5 at %) sample essentially reproduces the one previously observed in polycrystallineCdMg (3.38 at %), showing a steplike discontinuity and a logarithmic singularity. A complete different behaviour is observed inCdMg (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.