Electronic transport in EuB${}_6$

Abstract

EuB${}_6$ is a magnetic semiconductor in which defects introduce charge carriers into the conduction band with the Fermi energy varying with temperature and magnetic field. We present experimental and theoretical work on the electronic magnetotransport in single-crystalline EuB${}_6$. Magnetization, magnetoresistance and Hall effect data were recorded at temperatures between 2 and 300 K and in magnetic fields up to 5.5 T. The negative magnetoresistance is well reproduced by a model in which the spin disorder scattering is reduced by the applied magnetic field. The Hall effect can be separated into an ordinary and an anomalous part. At 20 K the latter accounts for half of the observed Hall voltage, and its importance decreases rapidly with increasing temperature. As for Gd and its compounds, where the rare-earth ion adopts the same Hund's rule ground state as Eu${}^{2+}$ in EuB${}_6$, the standard antisymmetric scattering mechanisms underestimate the $size$ of this contribution by several orders of magnitude, while reproducing its $shape$ almost perfectly. Well below the bulk ferromagnetic ordering at $T_C$ = 12.5 K, a two-band model successfully describes the magnetotransport. Our description is consistent with published de Haas van Alphen, optical reflectivity, angular-resolved photoemission, and soft X-ray emission as well as absorption data, but requires a new interpretation for the gap feature deduced from the latter two experiments.

35 pages, 12 figures, submitted to PRB

References in corpus (3)

• Point defects, ferromagnetism and transport in calcium hexaboride
• Bulk Band Gaps in Divalent Hexaborides
• Overlooked Contribution to the Hall Effect in Ferromagnetic Metals

Cited by in corpus (12)

• Magnetic semimetals and quantized anomalous Hall effect in EuB6
• Magnetic phase separation in EuB6 detected by muon spin rotation
• Percolation and Colossal Magnetoresistance in Eu-based Hexaborides
• Double Exchange Model for Magnetic Hexaborides
• Magnetic polarons and magnetoresistance in EuB6
• Magneto-optical evidence of double exchange in a percolating lattice
• Gradual transition from insulator to semimetal of Ca${}_{1-x}$Eu${}_x$B${}_6$ with increasing Eu concentration
• Possible quantum nematic in a colossal magnetoresistance material
• Magneto-optical behaviour of EuIn_2P_2
• Exploring itinerant states in divalent hexaborides using rare-earth $L$ edge resonant inelastic X-ray scattering
• Kondo Behavior of U in CaB${}_6$
• Anderson Localization Triggered by Spin Disorder---with an Application to Eu_x Ca_1-x B_6