• DOI:10.1103/PhysRevB.91.235104
• Corpus ID: 118399521

Charge transport in HoxLu1-xB12: Separating Positive and Negative Magnetoresistance in Metals with Magnetic Ions

@article{Sluchanko2015ChargeTI,
  title={Charge transport in HoxLu1-xB12: Separating Positive and Negative Magnetoresistance in Metals with Magnetic Ions},
  author={Nikolai Efimovich Sluchanko and A. L. Khoroshilov and Mikhail A. Anisimov and Andrey Azarevich and Aleksey Bogach and V Glushkov and Sergei V. Demishev and Vladimir N. Krasnorussky and Valerii V. Voronov and N. Yu. Shitsevalova and Vladimir B. Filippov and A. V. Levchenko and Gabriel Prist{\'a}{\vs} and S Gab{\'a}ni and K. Flachbart},
  journal={Physical Review B},
  year={2015},
  volume={91},
  pages={235104-1-235104-15}
}

• N. Sluchanko, A. Khoroshilov, +12 authors K. Flachbart
• Published 1 December 2014
• Physics
• Physical Review B

The magnetoresistance (MR) $\Delta \rho/\rho$ of cage-glass compound Ho$_x$Lu$_{1-x}$B$_{12}$ with various concentration of magnetic holmium ions ($x$$\leq$0.5) has been studied in detail concurrently with magnetization M(T) and Hall effect investigations on high quality single crystals at temperatures 1.9-120 K and in magnetic field up to 80 kOe. The undertaken analysis of $\Delta\rho/\rho$ allows us to conclude that the large negative magnetoresistance (nMR) observed in vicinity of Neel temperature is caused by scattering of charge carriers on magnetic clusters of Ho$^{3+}$ ions, and that these nanosize regions with AF exchange inside may be considered as short range order AF domains. It was shown that the Yosida relation $-\Delta \rho/\rho$$\sim$$M^2$ provides an adequate description of the nMR effect for the case of Langevin type behavior of magnetization. Moreover, a reduction of Ho-ion effective magnetic moments in the range 3-9$\mu_B$ was found to develop both with temperature lowering and under the increase of holmium content. A phenomenological description of the large positive quadratic contribution $\Delta \rho/\rho$$\sim$$\mu_D^2 H^2$ which dominates in Ho$_x$Lu$_{1-x}$B$_{12}$ in the intermediate temperature range 20-120 K allows to estimate the drift mobility exponential changes $\mu_D$$\sim$$T^{-a}$ with $a$=1.3-1.6 depending on Ho concentration. An even more comprehensive behavior of magnetoresistance has been found in the AF state of Ho$_x$Lu$_{1-x}$B$_{12}$ where an additional linear positive component was observed and attributed to charge carriers scattering on the spin density wave (SDW). High precision measurements of $\Delta\rho/\rho=f(H,T)$ have allowed us also to reconstruct the magnetic H-T phase diagram of Ho$_{0.5}$Lu$_{0.5}$B$_{12}$ and to resolve its magnetic structure as a superposition of 4f (based on localized moments) and 5d (based on SDW) components.