Static and dynamical properties of the ferromagnetic Kondo model with direct antiferromagnetic coupling between the localized t(2g) electrons

Article

关键词: DOUBLE-EXCHANGE;    PHASE-DIAGRAM;    LA1-XSRXMNO3;    MAGNETORESISTANCE;    PHOTOEMISSION;    CONDUCTIVITY;    RESISTIVITY;    MANGANITES;    SPECTRA;   

DOI  :  10.1103/PhysRevB.58.6403

来源: SCIE

【 摘 要 】

The phase diagram of the Kondo lattice Hamiltonian with ferromagnetic Hund's coupling in the limit where the spin of the localized ta, electrons is classical is analyzed in one dimension as a function of temperature, electronic density, and a direct antiferromagnetic coupling J' between the localized spins. Studying static and dynamical properties, a behavior that qualitatively resembles experimental results for manganites occurs for J' smaller than 0.11 in units of the eg hopping amplitude. In particular a coexistence of ferromagnetic and antiferromagnetic excitations is observed at low-hole density in agreement with neutron scattering experiments on La2-2xSr1+2xMn2O7 with x=0.4. This effect is caused by the recently reported tendency to phase separation between hole-rich ferromagnetic and hole-undoped antiferromagnetic domains in electronic models for manganites. As J' increases metal-insulator transitions are detected by monitoring the optical conductivity and the density of states. The magnetic correlations reveal the existence of spiral phases without long-range order but with fairly large correlation lengths. Indications of charge ordering effects appear in the analysis of charge correlations.

【 授权许可】

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