Theory of anomalous magnon softening in ferromagnetic manganites

Abstract

In metallic manganites with low Curie temperatures, a peculiar softening of the magnon spectrum close to the magnetic zone boundary has experimentally been observed. Here we present a theory of the renormalization of the magnetic excitation spectrum in colossal magnetoresistance compounds. The theory is based on the modulation of magnetic exchange bonds by the orbital degree of freedom of double-degenerate e_g electrons. The model considered is an orbitally degenerate double-exchange system coupled to Jahn-Teller active phonons which we treat in the limit of strong onsite repulsions. Charge and coupled orbital-lattice fluctuations are identified as the main origin of the unusual softening of the magnetic spectrum.

References in corpus (2)

• Electronic origin of magnetic and orbital ordering in insulating LaMnO_3
• Orbital dynamics: The origin of the anomalous optical spectra in ferromagnetic manganites

Cited by in corpus (49)

• Spin-controlled Mott-Hubbard bands in LaMnO_3 probed by optical ellipsometry
• Approach to the metal-insulator transition in La(1-x)CaxMnO3 (0<x<.2): magnetic inhomogeneity and spin wave anomaly
• Magnon Damping by magnon-phonon coupling in Manganese Perovskites
• Order from disorder: Quantum spin gap in magnon spectra of LaTiO_3
• Orbital excitations in LaMnO${}_3$
• Low-energy Mott-Hubbard excitations in LaMnO_3 probed by optical ellipsometry
• Optical study of orbital excitations in transition-metal oxides
• Spectacular doping dependence of interlayer exchange and other results on spin waves in bilayer manganites
• Multicritical end-point of the first-order ferromagnetic transition in colossal magnetoresistive manganites
• Spin dynamical properties and orbital states of the layered perovskite La_2-2x_Sr_1+2x_Mn_2_O_7 (0.3 <= x < 0.5)
• Evolution of spin-wave excitations in ferromagnetic metallic manganites
• Competing exchange interactions on the verge of a metal-insulator transition in the two-dimensional spiral magnet Sr${}_3$Fe${}_2$O${}_7$
• A novel spin wave expansion, finite temperature corrections and order from disorder effects in the double exchange model
• Magnons in Ferromagnetic Metallic Manganites
• Spin-Orbital Order Modified by Orbital Dilution in Transition Metal Oxides: From Spin Defects to Frustrated Spins Polarizing Host Orbitals
• Site-selective Probe of Magnetic Excitations in Rare-earth Nickelates using Resonant Inelastic X-ray Scattering
• Complex orbital state in manganites
• Spin waves throughout the Brillouin zone and magnetic exchange coupling in ferromagnetic metallic manganites La${}_{1-x}$Ca${}_x$MnO${}_3$ ($x=0.25,0.30$)
• Low-temperature electrical transport in bilayer manganite La${}_{1.2}$Sr${}_{1.8}$Mn${}_2$O${}_7$
• Ferromagnetism in the t-t' Hubbard model: interplay of lattice, band dispersion, and interaction effects studied within a Goldstone-mode preserving scheme
• Effects of the On-Site Coulomb Repulsion in Double Exchange Magnets
• Three--body Correlation Effects on the Spin Dynamics of Double--Exchange Ferromagnets
• Non--Heisenberg Spin Dynamics of Double-Exchange Ferromagnets with Coulomb Repulsion
• Anomaly in Spin Excitation Spectrum of Double-Exchange Systems with Randomness
• Optical phase diagram of perovskite-type colossal magnetoresistance manganites with near-half doping
• Diffuse Neutron Scattering Study of Magnetic Correlations in half-doped La0.5Ca0.5-xSrxMnO3 (x = 0.1, 0.3 and 0.4) Manganites
• Jahn-Teller effect and Electron correlation in manganites
• Charge and orbital order in transition metal oxides
• Spin wave dispersion softening in the ferromagnetic Kondo lattice model for manganites
• Spectral Function Analysis on Spin Dynamics in Double-Exchange Systems with Randomness
• Spin-charge coupling in a band ferromagnet: magnon-energy reduction, anomalous softening, and damping
• Magnetization Relaxation and Collective Spin Excitations in Correlated Double--Exchange Ferromagnets
• Colossal magnetoresistance and quenched disorder in manganese oxides
• Orbital fluctuations, spin-orbital coupling, and anomalous magnon softening in an orbitally degenerate ferromagnet
• Green's function variational approach to orbital polarons in KCuF3
• Spin excitations used to probe the nature of the exchange coupling in the magnetically ordered ground state of Pr${}_{0.5}$Ca${}_{0.5}$MnO${}_3$
• Magnon softening and damping in the ferromagnetic manganites due to orbital correlations
• Order from disorder in the double-exchange model
• Interacting chains of orbital polarons in "Colossal" magnetoresistive La1-xSrxMnO3 revealed by spin and lattice dynamics
• Orbital-ordering-induced anomalous softening of the ferromagnetic spin waves in perovskite manganites
• Whither Correlated Electron Theory?
• Magnon dressing by orbital excitations in ferromagnetic planes of K${}_2$CuF${}_4$ and LaMnO${}_3$
• Study of the spin-$\frac{3}{2}$ Hubbard-Kondo lattice model by means of the Composite Operator Method
• Spin-wave softening and Hund's coupling in ferromagnetic manganites
• Spin-charge and spin-orbital coupling effects on spin dynamics in ferromagnetic manganites
• Concurrence of topological electrons and magnons in the Kagome ferromagnet CoCu3(OH)6Cl2
• Magnon damping and mode softening in quantum double-exchange ferromagnets
• Perturbative calculation of the spin-wave dispersion in a disordered double-exchange model
• Orbital liquid in the $e_g$ orbital Hubbard model in $d=\infty$ dimensions