Anomalous thermal transport in double-layered perovskite manganite La1.2Sr1.8Mn2O7

The in-plane (kappa(ab)) and out-of-plane (kappa(c)) thermal conductivity o f a double-layered Mn perovskite single crystal La1.2Sr1.8Mn2O7 has been st udied as a function of magnetic field (0 less than or equal to H less than or equal to 18T) parallel to the MnO2 plane at several fixed temperatures. A held-induced large enhancement was observed in the value of kappa(ab) aro und T-c. However, the value of kappa(c) did not display such a remarkable i ncrease and was almost independent of the filed upto 18 T. The observed gia nt magnetothermal conductivity was more enhanced and extended beyond T-c in contrast with the cubic Mn perovskites. (C) 2000 Elsevier Science B.V. All rights reserved.