We have studied thermal conductivity, thermopower, and resistivity of bulk polycrystalline ${\mathrm{La}}_{0.8}$${\mathrm{Ca}}_{0.2}$${\mathrm{MnO}}_3$. Large changes in the magnetothermal conductivity of about 15% and the thermopower as large as 80% were found in addition to a large magnetoresistivity of 80% around the magnetic transition temperature at 240 K. The temperature dependence of the thermal conductivity displays a striking dip, while the resistivity and the thermopower have a peak near 240 K. The temperature and field dependences of the thermal conductivity are attributed to the scattering of the phonons by spin fluctuations.

• Received 27 January 1997

DOI:https://doi.org/10.1103/PhysRevB.55.15471