Magnon Excitation Spectrum in Ferromagnetic Quasicubic Manganites

2010 ◽  
Vol 46 (6) ◽  
pp. 1295-1298 ◽  
Author(s):  
P. Schlottmann
Keyword(s):  
Excitation Spectrum ◽  
Spin Wave ◽  
Heisenberg Model ◽  
Double Exchange ◽  
Zone Boundary ◽  
Wave Approximation ◽  
Hund’S Rule ◽  
Jahn Teller ◽  
Hund's Rule ◽  
Magnon Excitation

The magnon excitation spectrum of ferromagnetic quasicubic manganites is studied by using the linearized spin-wave approximation for the double-exchange and the superexchange interactions. Two situations are distinguished: 1) a rigid coupling of the t2gand egspins via a large Hund's rule coupling and 2) a softened coupling between these spins (e.g., due to coupling of the egelectrons to Jahn-Teller modes). Case 2) leads to a softening of the magnon dispersion (compared to the Heisenberg model) close to the zone boundary.

ON THE QUANTUM KAGOMÉ ANTIFERROMAGNET

1995 ◽  
Vol 09 (08) ◽  
pp. 933-959 ◽  
Author(s):  
HITOSHI ASAKAWA ◽  
MASUO SUZUKI
Keyword(s):  
Physical Properties ◽  
Excitation Spectrum ◽  
Spin Wave ◽  
Heisenberg Model ◽  
Present Model ◽  
Quantum Fluctuations ◽  
Wave Theory ◽  
Local Symmetry ◽  
Higher Order ◽  
Antiferromagnetic Heisenberg Model

The purpose of the present paper is to review investigations of the antiferromagnetic Heisenberg model on the kagomé lattice and to propose some schemes based on the spin-wave theory by which physical properties of the present model can be better understood. By means of our schemes, it is shown that the linear-spin-wave flat mode of the present model comes from the semi-local symmetry of the linear-spin-wave Hamiltonian, where the flat mode has an excitation-spectrum with ω≡0 for all k. It is also shown that the inclusion of higher-order quantum fluctuations may break the symmetry and thereby the flat mode may be lifted up.

Effects of the Hund's Rule Coupling in an Orbitally Degenerate Anderson Model

1999 ◽  
Vol 68 (7) ◽  
pp. 2317-2325 ◽  
Author(s):  
Katsunori Kubo ◽  
Dai S. Hirashima
Keyword(s):  
Anderson Model ◽  
Hund’S Rule ◽  
Hund's Rule

Hund's-Rule Effect in Degenerate Anderson Model

1981 ◽  
Vol 103 (2) ◽  
pp. 769-774 ◽  
Author(s):  
A. M. Oleś ◽  
K. A. Chao
Keyword(s):  
Anderson Model ◽  
Hund’S Rule ◽  
Hund's Rule
Sign in / Sign up

Export Citation Format

Share Document