Theory of spin wave excitation in manganites

Abstract

The role of the orbital degrees of freedom is studied theoretically for the spin dynamics of $R_{1-x}{A}_x$MnO${}_3$. Based on the meanfield solution, an RPA calculation has been done and it is found that the $d_{x^2-y^2}$-type orbital is essential for the double-exchange (DE) interactions, i.e., the DE is basically two-dimensional interaction. Based on this results compared with experiments, we propose that the orbital wavefunction is $d_{x^2-y^2}$-type locally even in the metallic ferromagnetic state, which fluctuate quantum mechanically. Well agreement of the estimation with experiments suggest that the Jahn-Teller phonon has less importance on the spin dynamics.

References in corpus (2)

• Hole concentration induced transformation of the magnetic and orbital structure in Nd{1-x}Sr{x}MnO{3}
• Transition between two ferromagnetic states driven by orbital ordering in La_{0.88}Sr_{0.12}MnO_3

Cited by in corpus (4)

• Magnons in Ferromagnetic Metallic Manganites
• Spin Waves in Canted Phases: An Application to Doped Manganites
• Spin-Orbital Wave Excitations in Orbitally Degenerate Exchange Model with Multipolar Interactions
• Jahn-Teller effect and Electron correlation in manganites