Polaron-mediated spin correlations in metallic and insulating La${}_{1-x}{A}_x$MnO${}_3$ ($A$=Ca, Sr, or Ba)

Abstract

Neutron spectroscopy measurements reveal short-range spin correlations near and above the ferromagnetic-paramagnetic phase transition in manganite materials of the form La${}_{1-x}{A}_x$MnO${}_3$, including samples with an insulating ground state as well as colossal magnetoresistive samples with a metallic ground state. Quasielastic magnetic scattering is revealed that forms clear ridges running along the [100]-type directions in momentum space. A simple model consisting of a conduction electron hopping between spin polarized Mn ions that becomes self-trapped after a few hops captures the essential physics of this magnetic component of the scattering. We associate this scattering component with the magnetic part of diffuse polarons, as we observe a temperature dependence similar to that of the diffuse structural scattering arising from individual polarons.

8 pages, 6 figures

References in corpus (4)

• Phase instability induced by polar nanoregions in a relaxor ferroelectric system
• Coexistence and competition of local- and long-range polar orders in a ferroelectric relaxor
• Magnons in Ferromagnetic Metallic Manganites
• Paramagnetic Spin Correlations in Colossal Magnetoresistive La0.7Ca0.3MnO3

Cited by in corpus (2)

• Spin wave damping arising from phase coexistence below $T_c$ in colossal magnetoresistive La${}_{0.7}$Ca${}_{0.3}$MnO${}_3$
• Damping and softening of transverse acoustic phonons in colossal magnetoresistive La${}_{0.7}$Ca${}_{0.3}$MnO${}_3$ and La${}_{0.7}$Sr${}_{0.3}$MnO${}_3$