Spin Waves in Canted Phases: An Application to Doped Manganites

TL;DR

This paper develops an effective theory for low-energy spin waves in canted magnetic phases of doped manganites, highlighting their unique features and doping dependence, which can help distinguish phases experimentally.

Contribution

It introduces a next-to-leading order effective Lagrangian for spin waves in canted phases, incorporating symmetry considerations and charge interactions, with implications for doped manganites.

Findings

Derived doping-dependent dispersion relations.

Identified distinctive spin wave characteristics.

Proposed experimental differentiation of phases.

Abstract

We present the effective lagrangian for low energy and momentum spin waves in canted phases at next to leading order in the derivative expansion. The symmetry breaking pattern SU(2) --> 1 of the internal spin group and that of the crystallographic space group imply that there is one ferromagnetic and one antiferromagnetic spin wave. The interaction of the spin waves with the charge carriers is also discussed for canted, ferromagnetic and antiferromagnetic phases. All this together allows us to write the doping dependence of the dispersion relation parameters for doped manganites. We point out that the spin waves posses distinctive characteristics which may allow us to experimentally differentiate canted phases from phase separation regions in doped manganites.