Enhanced giant magnetothermal conductivity 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 temperature (10 less than or equal to T less than or equal to 300 K) and magnetic field (0 less than or equal to H less than or equal to 18 T). Near the insulating paramagnetic-to-metallic ferromagnetic transition, an anomaly in the value of kappa(ab) was observed, whereas the value of kappa(c) did not reveal such an anomaly. The observed giant magne tothermal conductivity was enhanced and extended beyond T-c in contrast wit h the cubic Mn perovskites. Our data seem to indicate the significant role played by the two-dimensional structure and the spin-lattice coupling.