Phonon thermal conductivity in single layered manganites

We present measurements of the thermal transport in single crystals of single-layered manganites La1-xSr1+xMnO4 with 0 <= x <= 0.5. The data reveal a strong but non-monotonic suppression of the phonon thermal conductivity kappa(ph) upon hole-doping. The suppression of originates from scattering of phonons by polaronic holes. The suppression is particularly strong when charge and orbital degrees of freedom are disordered and rather weak in the case of long-range charge and orbital ordering. Moreover, slight anomalies are found in the vicinity of antiferromagnetic phase transitions, probably due to scattering of phonons by magnetic fluctuations. (c) 2004 Elsevier B.V. All rights reserved.