Double Exchange Model for Magnetic Hexaborides

Abstract

A microscopic theory for rare-earth ferromagnetic hexaborides, such as Eu(1-x)Ca(x)B6, is proposed on the basis of the double-exchange Hamiltonian. In these systems, the reduced carrier concentrations place the Fermi level near the mobility edge, introduced in the spectral density by the disordered spin background. We show that the transport properties such as Hall effect, magnetoresitance, frequency dependent conductivity, and DC resistivity can be quantitatively described within the model. We also make specific predictions for the behavior of the Curie temperature, Tc, as a function of the plasma frequency, omega_p.

4 pages, 3 figures

References in corpus (10)

• Electronic and Magnetic States in the Giant Magneto-resistive Compounds
• Point defects, ferromagnetism and transport in calcium hexaboride
• Bulk Band Gaps in Divalent Hexaborides
• Magnetic Polarons and the Metal-Semiconductor Transition in (Eu,La)B6 and EuO: Raman Scattering Studies
• Charge Localization in Disordered Colossal-Magnetoresistance Manganites
• Electronic Fine Structure in the Electron-Hole Plasma in SrB6
• Electronic transport in EuB${}_6$
• Fluctuation induced hopping and spin polaron transport
• Optical evidence for a spin-filter effect in the charge transport of $E{u}_{0.6}C{a}_{0.4}{B}_6$
• Magneto-optical Kerr effect in $E{u}_{1-x}C{a}_x{B}_6$

Cited by in corpus (9)

• Electrodynamics of Correlated Electron Materials
• Electronic properties of EuB6 in the ferromagnetic regime: Half-metal versus semiconductor
• 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
• Magnetic exchange mechanism for electronic gap opening in graphene
• Magneto-optical behaviour of EuIn_2P_2
• Near room-temperature ferromagnetism from double-exchange in the van der Waals material CrGeTe${}_3$: evidence from optical conductivity under pressure
• Anderson Localization Triggered by Spin Disorder---with an Application to Eu_x Ca_1-x B_6
• Enhanced ferromagnetism from electron-electron interactions in double exchange type models