Heat Conduction and Magnetic Phase Behavior in Electron-Doped Ca_{1-x} La_x MnO_3(0 <= x <= 0.2)

TL;DR

This study investigates how electron doping affects heat conduction and magnetic phase transitions in Ca_{1-x} La_x MnO_3, revealing strong phonon-spin coupling and magnetoelastic polaron formation at low doping levels.

Contribution

It provides new insights into the interplay between thermal conductivity, magnetic behavior, and electron doping in Ca_{1-x} La_x MnO_3, especially at low doping levels.

Findings

Enhanced thermal conductivity below T_N for undoped sample.

Nonmonotonic behavior of kappa with increasing x.

Magnetoelastic polaron formation influences heat and magnetic properties.

Abstract

Measurements of thermal conductivity (kappa) vs temperature are reported for a series of Ca_{1-x} La_x MnO_3(0 <= x <= 0.2) specimens. For the undoped (x=0), G-type antiferromagnetic compound a large enhancement of kappa below the Neel temperature (T_N ~ 125 K) indicates a strong coupling of heat-carrying phonons to the spin system. This enhancement exhibits a nonmonotonic behavior with increasing x and correlates remarkably well with the small ferromagnetic component of the magnetization reported previously [Neumeier and Cohn, Phys. Rev. B 61 14319 (2000).] Magnetoelastic polaron formation appears to underly the behavior of kappa and the magnetization at x <= 0.02.