Magnetoresistance scaling and the anisotropy of charge carrier scattering in the paramagnetic phase of Ho$_{0.8}$Lu$_{0.2}$B$_{12}$ cage glass

The transverse magnetoresistance of Ho$_{0.8}$Lu$_{0.2}$B$_{12}$ dodecaboride with a cage glass structure is studied at low (2–10 K) temperatures. It is demonstrated that the isotropic negative magnetoresistance in this antiferromagnet is dominant within the broad temperature range near $T_{\mathrm{N}}\approx \mathrm{K}$. This contribution to the total magnetoresistance is due to the scattering of charge carriers by nanoclusters formed by Но$^{3+}$ ions, and it can be scaled in the $\rho=f(\mu_{\text{eff}}^2H^2/T^2)$ representation. It is found that the magnetoresistance anisotropy above (about 15% at 80 kOe) is due to the positive contribution, which achieves maximum values at the magnetic field direction close to $\mathbf{H}\| [001]$. The anisotropy of the charge carrier scattering is interpreted in terms of the cooperative dynamic Jahn–Teller effect at В12 clusters.